diff --git a/BUILD b/BUILD
index 6611edcf..bcae6ce4 100644
--- a/BUILD
+++ b/BUILD
@@ -120,7 +120,7 @@ tcl_srcs = [
     "tcl/CmdArgs.tcl",
     "tcl/Property.tcl",
     "tcl/Sta.tcl",
-    "tcl/Variables.tcl",
+    "sdc/Variables.tcl",
     "tcl/Splash.tcl",
     "graph/Graph.tcl",
     "liberty/Liberty.tcl",
@@ -147,7 +147,7 @@ exported_tcl = [
     "tcl/Property.tcl",
     "tcl/Splash.tcl",
     "tcl/Sta.tcl",
-    "tcl/Variables.tcl",
+    "sdc/Variables.tcl",
     "sdc/Sdc.tcl",
     "sdf/Sdf.tcl",
     "search/Search.tcl",
diff --git a/CMakeLists.txt b/CMakeLists.txt
index a6eaddaf..f8ddda84 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -257,7 +257,6 @@ set(STA_TCL_FILES
   tcl/Property.tcl
   tcl/Sta.tcl
   tcl/Splash.tcl
-  tcl/Variables.tcl
   dcalc/DelayCalc.tcl
   graph/Graph.tcl
   liberty/Liberty.tcl
@@ -267,6 +266,7 @@ set(STA_TCL_FILES
   parasitics/Parasitics.tcl
   power/Power.tcl
   sdc/Sdc.tcl
+  sdc/Variables.tcl
   sdf/Sdf.tcl
   search/Search.tcl
   spice/WriteSpice.tcl
diff --git a/dcalc/ArnoldiDelayCalc.cc b/dcalc/ArnoldiDelayCalc.cc
index 502a73eb..0fda825f 100644
--- a/dcalc/ArnoldiDelayCalc.cc
+++ b/dcalc/ArnoldiDelayCalc.cc
@@ -127,6 +127,7 @@ class ArnoldiDelayCalc : public LumpedCapDelayCalc
 {
 public:
   ArnoldiDelayCalc(StaState *sta);
+  ArnoldiDelayCalc(const ArnoldiDelayCalc &dcalc);
   ~ArnoldiDelayCalc() override;
   ArcDelayCalc *copy() override;
   std::string_view name() const override { return "arnoldi"; }
@@ -262,10 +263,20 @@ ArnoldiDelayCalc::ArnoldiDelayCalc(StaState *sta) :
   _slewV = (double*)malloc(_pinNmax * sizeof(double));
 }
 
+ArnoldiDelayCalc::ArnoldiDelayCalc(const ArnoldiDelayCalc &dcalc) :
+  LumpedCapDelayCalc(dcalc),
+  reduce_(new ArnoldiReduce(this)),
+  delay_work_(delay_work_create())
+{
+  _pinNmax = dcalc._pinNmax;
+  _delayV = (double*)malloc(_pinNmax * sizeof(double));
+  _slewV = (double*)malloc(_pinNmax * sizeof(double));
+}
+
 ArcDelayCalc *
 ArnoldiDelayCalc::copy()
 {
-  return new ArnoldiDelayCalc(this);
+  return new ArnoldiDelayCalc(*this);
 }
 
 ArnoldiDelayCalc::~ArnoldiDelayCalc()
diff --git a/dcalc/CcsCeffDelayCalc.cc b/dcalc/CcsCeffDelayCalc.cc
index 848ac227..9de98d81 100644
--- a/dcalc/CcsCeffDelayCalc.cc
+++ b/dcalc/CcsCeffDelayCalc.cc
@@ -60,12 +60,23 @@ CcsCeffDelayCalc::CcsCeffDelayCalc(StaState *sta) :
 {
 }
 
-CcsCeffDelayCalc::~CcsCeffDelayCalc() { delete table_dcalc_; }
+CcsCeffDelayCalc::CcsCeffDelayCalc(const CcsCeffDelayCalc &dcalc) :
+  LumpedCapDelayCalc(dcalc),
+  watch_pin_values_(dcalc.network_),
+  capacitance_unit_(dcalc.capacitance_unit_),
+  table_dcalc_(makeDmpCeffElmoreDelayCalc(this))
+{
+}
+
+CcsCeffDelayCalc::~CcsCeffDelayCalc()
+{
+  delete table_dcalc_;
+}
 
 ArcDelayCalc *
 CcsCeffDelayCalc::copy()
 {
-  return new CcsCeffDelayCalc(this);
+  return new CcsCeffDelayCalc(*this);
 }
 
 ArcDcalcResult
diff --git a/dcalc/CcsCeffDelayCalc.hh b/dcalc/CcsCeffDelayCalc.hh
index 07a659b9..90f27561 100644
--- a/dcalc/CcsCeffDelayCalc.hh
+++ b/dcalc/CcsCeffDelayCalc.hh
@@ -39,6 +39,7 @@ class CcsCeffDelayCalc : public LumpedCapDelayCalc,
 {
 public:
   CcsCeffDelayCalc(StaState *sta);
+  CcsCeffDelayCalc(const CcsCeffDelayCalc &dcalc);
   ~CcsCeffDelayCalc() override;
   ArcDelayCalc *copy() override;
   std::string_view name() const override { return "ccs_ceff"; }
diff --git a/dcalc/DmpCeff.cc b/dcalc/DmpCeff.cc
index 7ce3e903..5d0aef1d 100644
--- a/dcalc/DmpCeff.cc
+++ b/dcalc/DmpCeff.cc
@@ -68,6 +68,17 @@ static const char *dmp_func_index_strings[] = {"y20", "y50", "Ipi"};
 static double
 exp2(double x);
 
+static double
+gateModelRd(const LibertyCell *cell,
+            const GateTableModel *gate_model,
+            const RiseFall *rf,
+            double in_slew,
+            double c2,
+            double c1,
+            const Pvt *pvt);
+
+////////////////////////////////////////////////////////////////
+
 class DmpError : public Exception
 {
 public:
@@ -78,156 +89,13 @@ private:
   std::string what_;
 };
 
-static double
-gateModelRd(const LibertyCell *cell,
-            const GateTableModel *gate_model,
-            const RiseFall *rf,
-            double in_slew,
-            double c2,
-            double c1,
-            const Pvt *pvt);
-////////////////////////////////////////////////////////////////
-
-// Base class for Dartu/Menezes/Pileggi algorithm.
-// Derived classes handle different cases of zero values in the Pi model.
-class DmpAlg : public StaState
+DmpError::DmpError(std::string_view what) :
+  what_(what)
 {
-public:
-  DmpAlg(int nr_order,
-         StaState *sta);
-  ~DmpAlg() override = default;
-  virtual std::string_view name() = 0;
-  // Set driver model and pi model parameters for delay calculation.
-  virtual void init(const LibertyLibrary *library,
-                    const LibertyCell *drvr_cell,
-                    const Pvt *pvt,
-                    const GateTableModel *gate_model,
-                    const RiseFall *rf,
-                    double rd,
-                    double in_slew,
-                    double c2,
-                    double rpi,
-                    double c1);
-  virtual std::pair<double, double> gateDelaySlew() = 0;
-  virtual std::pair<double, double> loadDelaySlew(const Pin *load_pin,
-                                                  double elmore);
-  double ceff() { return ceff_; }
+  //sta::print(stdout, "DmpError {}\n", what);
+}
 
-  // Given x_ as a vector of input parameters, fill fvec_ with the
-  // equations evaluated at x_ and fjac_ with the jabobian evaluated at x_.
-  virtual void evalDmpEqns() = 0;
-  // Output response to vs(t) ramp driving pi model load (vo, dvo_dt).
-  std::pair<double, double> Vo(double t);
-  // Load response to driver waveform (vl, dvl/dt).
-  std::pair<double, double> Vl(double t);
-
-protected:
-  void luDecomp();
-  void luSolve();
-  void newtonRaphson();
-  // Find driver parameters t0, delta_t, Ceff.
-  void findDriverParams(double ceff);
-  std::pair<double, double> gateCapDelaySlew(double ceff);
-  std::tuple<double, double, double> gateDelays(double ceff);
-  // Partial derivatives of y(t) jacobian (dydt0, dyddt, dydcl).
-  std::tuple<double, double, double> dy(double t,
-                                        double t0,
-                                        double dt,
-                                        double cl);
-  double y0dt(double t,
-              double cl);
-  double y0dcl(double t,
-               double cl);
-  void showX();
-  void showFvec();
-  void showJacobian();
-  std::pair<double, double> findDriverDelaySlew();
-  double findVoCrossing(double vth,
-                        double t_lower,
-                        double t_upper);
-  void showVo();
-  double findVlCrossing(double vth,
-                        double t_lower,
-                        double t_upper);
-  void showVl();
-  void fail(std::string_view reason);
-
-  // Output response to vs(t) ramp driving capacitive load (y, t1).
-  std::pair<double, double> y(double t,
-                              double t0,
-                              double dt,
-                              double cl);
-  // Output response to unit ramp driving capacitive load.
-  double y0(double t,
-            double cl);
-  // Output response to unit ramp driving pi model load.
-  // Unit ramp output at pi load (vo, dvo_dt).
-  virtual std::pair<double, double> V0(double t) = 0;
-  // Upper bound on time that vo crosses vh.
-  virtual double voCrossingUpperBound() = 0;
-  // Load responce to driver unit ramp.
-  // Unit ramp load response (vl, dvl_dt).
-  virtual std::pair<double, double> Vl0(double t) = 0;
-  // Upper bound on time that vl crosses vh.
-  double vlCrossingUpperBound();
-
-  // Inputs to the delay calculator.
-  const LibertyCell *drvr_cell_;
-  const LibertyLibrary *drvr_library_;
-  const Pvt *pvt_;
-  const GateTableModel *gate_model_;
-  double in_slew_;
-  double c2_{0.0};
-  double rpi_{0.0};
-  double c1_{0.0};
-
-  double rd_;
-  // Logic threshold (percentage of supply voltage).
-  double vth_;
-  // Slew lower limit (percentage of supply voltage).
-  double vl_;
-  // Slew upper limit (percentage of supply voltage).
-  double vh_;
-  // Table slews are scaled by slew_derate to get
-  // measured slews from vl to vh.
-  double slew_derate_;
-
-  // Driver parameters calculated by this algorithm.
-  double t0_;
-  double dt_;
-  double ceff_;
-
-  // Driver parameter Newton-Raphson state.
-  int nr_order_;
-
-  static constexpr int max_nr_order_ = 3;
-
-  std::array<double, max_nr_order_> x_;
-  std::array<double, max_nr_order_> fvec_;
-  std::array<std::array<double, max_nr_order_>, max_nr_order_> fjac_;
-  std::array<double, max_nr_order_> scale_;
-  std::array<double, max_nr_order_> p_;
-  std::array<int, max_nr_order_> index_;
-
-  // Driver slew used to check load delay.
-  double drvr_slew_;
-  double vo_delay_;
-  // True if the driver parameters are valid for finding the load delays.
-  bool driver_valid_;
-  // Load rspf elmore delay.
-  double elmore_;
-  double p3_;
-
-  // Tolerance (as a scale of value) for driver parameters (Ceff, delta t, t0).
-  static constexpr double driver_param_tol_ = .01;
-  // Waveform threshold crossing time tolerance (1.0 = 100%).
-  static constexpr double vth_time_tol_ = .01;
-  // Max iterations for findRoot.
-  static constexpr int find_root_max_iter_ = 20;
-  static inline int newton_raphson_max_iter_ = 100;
-  // A small number used by luDecomp.
-  static constexpr double tiny_double_ = 1.0e-20;
-};
+////////////////////////////////////////////////////////////////
 
 DmpAlg::DmpAlg(int nr_order,
                StaState *sta) :
@@ -593,33 +461,6 @@ DmpAlg::fail(std::string_view reason)
 
 ////////////////////////////////////////////////////////////////
 
-// Capacitive load.
-class DmpCap : public DmpAlg
-{
-public:
-  DmpCap(StaState *sta);
-  std::string_view name() override { return "cap"; }
-  void init(const LibertyLibrary *library,
-            const LibertyCell *drvr_cell,
-            const Pvt *pvt,
-            const GateTableModel *gate_model,
-            const RiseFall *rf,
-            double rd,
-            double in_slew,
-            double c2,
-            double rpi,
-            double c1) override;
-  std::pair<double, double> gateDelaySlew() override;
-  std::pair<double, double> loadDelaySlew(const Pin *,
-                                           double elmore) override;
-  void evalDmpEqns() override;
-
-protected:
-  double voCrossingUpperBound() override;
-  std::pair<double, double> V0(double t) override;
-  std::pair<double, double> Vl0(double t) override;
-};
-
 DmpCap::DmpCap(StaState *sta) :
   DmpAlg(1,
          sta)
@@ -692,53 +533,6 @@ DmpCap::Vl0(double)
 
 ////////////////////////////////////////////////////////////////
 
-// No non-zero pi model parameters, two poles, one zero
-class DmpPi : public DmpAlg
-{
-public:
-  DmpPi(StaState *sta);
-  std::string_view name() override { return "Pi"; }
-  void init(const LibertyLibrary *library,
-            const LibertyCell *drvr_cell,
-            const Pvt *pvt,
-            const GateTableModel *gate_model,
-            const RiseFall *rf,
-            double rd,
-            double in_slew,
-            double c2,
-            double rpi,
-            double c1) override;
-  std::pair<double, double> gateDelaySlew() override;
-  void evalDmpEqns() override;
-
-protected:
-  double voCrossingUpperBound() override;
-  std::pair<double, double> V0(double t) override;
-  std::pair<double, double> Vl0(double t) override;
-
-private:
-  void findDriverParamsPi();
-  double ipiIceff(double t0,
-                  double dt,
-                  double ceff_time,
-                  double ceff);
-
-  // Poles/zero.
-  double p1_{0.0};
-  double p2_{0.0};
-  double z1_{0.0};
-  // Residues.
-  double k0_{0.0};
-  double k1_{0.0};
-  double k2_{0.0};
-  double k3_{0.0};
-  double k4_{0.0};
-  // Ipi coefficients.
-  double A_{0.0};
-  double B_{0.0};
-  double D_{0.0};
-};
-
 DmpPi::DmpPi(StaState *sta) :
   DmpAlg(3,
          sta)
@@ -940,18 +734,6 @@ DmpPi::voCrossingUpperBound()
 
 ////////////////////////////////////////////////////////////////
 
-// Capacitive load, so Ceff is known.
-// Solve for t0, delta t.
-class DmpOnePole : public DmpAlg
-{
-public:
-  DmpOnePole(StaState *sta);
-  void evalDmpEqns() override;
-
-protected:
-  double voCrossingUpperBound() override;
-};
-
 DmpOnePole::DmpOnePole(StaState *sta) :
   DmpAlg(2,
          sta)
@@ -1000,40 +782,6 @@ DmpOnePole::voCrossingUpperBound()
 
 ////////////////////////////////////////////////////////////////
 
-// C2 = 0, one pole, one zero.
-class DmpZeroC2 : public DmpOnePole
-{
-public:
-  DmpZeroC2(StaState *sta);
-  std::string_view name() override { return "c2=0"; }
-  void init(const LibertyLibrary *drvr_library,
-            const LibertyCell *drvr_cell,
-            const Pvt *pvt,
-            const GateTableModel *gate_model,
-            const RiseFall *rf,
-            double rd,
-            double in_slew,
-            double c2,
-            double rpi,
-            double c1) override;
-  std::pair<double, double> gateDelaySlew() override;
-
-protected:
-  std::pair<double, double> V0(double t) override;
-  std::pair<double, double> Vl0(double t) override;
-  double voCrossingUpperBound() override;
-
-private:
-  // Pole/zero.
-  double p1_{0.0};
-  double z1_{0.0};
-  // Residues.
-  double k0_{0.0};
-  double k1_{0.0};
-  double k2_{0.0};
-  double k3_{0.0};
-};
-
 DmpZeroC2::DmpZeroC2(StaState *sta) :
   DmpOnePole(sta)
 {
@@ -1260,19 +1008,12 @@ bool DmpCeffDelayCalc::unsuppored_model_warned_ = false;
 
 DmpCeffDelayCalc::DmpCeffDelayCalc(StaState *sta) :
   LumpedCapDelayCalc(sta),
-  dmp_cap_(new DmpCap(sta)),
-  dmp_pi_(new DmpPi(sta)),
-  dmp_zero_c2_(new DmpZeroC2(sta))
+  dmp_cap_(sta),
+  dmp_pi_(sta),
+  dmp_zero_c2_(sta)
 {
 }
 
-DmpCeffDelayCalc::~DmpCeffDelayCalc()
-{
-  delete dmp_cap_;
-  delete dmp_pi_;
-  delete dmp_zero_c2_;
-}
-
 ArcDcalcResult
 DmpCeffDelayCalc::gateDelay(const Pin *drvr_pin,
                             const TimingArc *arc,
@@ -1362,15 +1103,15 @@ DmpCeffDelayCalc::setCeffAlgorithm(const LibertyLibrary *drvr_library,
         || rpi < rd * 1e-3
         // c1/Rpi can be ignored.
         || (c1 == 0.0 || c1 < c2 * 1e-3 || rpi == 0.0))
-      dmp_alg_ = dmp_cap_;
+      dmp_alg_ = &dmp_cap_;
     else if (c2 < c1 * 1e-3)
-      dmp_alg_ = dmp_zero_c2_;
+      dmp_alg_ = &dmp_zero_c2_;
     else
       // The full monty.
-      dmp_alg_ = dmp_pi_;
+      dmp_alg_ = &dmp_pi_;
   }
   else
-    dmp_alg_ = dmp_cap_;
+    dmp_alg_ = &dmp_cap_;
   dmp_alg_->init(drvr_library, drvr_cell, pvt, gate_model, rf, rd, in_slew,
                  c2, rpi, c1);
   debugPrint(debug_, "dmp_ceff", 3,
@@ -1473,15 +1214,9 @@ void
 DmpCeffDelayCalc::copyState(const StaState *sta)
 {
   StaState::copyState(sta);
-  dmp_cap_->copyState(sta);
-  dmp_pi_->copyState(sta);
-  dmp_zero_c2_->copyState(sta);
-}
-
-DmpError::DmpError(std::string_view what) :
-  what_(what)
-{
-  //sta::print(stdout, "DmpError {}\n", what);
+  dmp_cap_.copyState(sta);
+  dmp_pi_.copyState(sta);
+  dmp_zero_c2_.copyState(sta);
 }
 
 // This saves about 2.5% in overall run time on designs with SPEF.
diff --git a/dcalc/DmpCeff.hh b/dcalc/DmpCeff.hh
index 1ca6209e..a2e8a144 100644
--- a/dcalc/DmpCeff.hh
+++ b/dcalc/DmpCeff.hh
@@ -32,19 +32,275 @@
 
 namespace sta {
 
-class DmpAlg;
-class DmpCap;
-class DmpPi;
-class DmpZeroC2;
 class GateTableModel;
 
+// Base class for Dartu/Menezes/Pileggi algorithm.
+// Derived classes handle different cases of zero values in the Pi model.
+class DmpAlg : public StaState
+{
+public:
+  DmpAlg(int nr_order,
+         StaState *sta);
+  ~DmpAlg() override = default;
+  virtual std::string_view name() = 0;
+  // Set driver model and pi model parameters for delay calculation.
+  virtual void init(const LibertyLibrary *library,
+                    const LibertyCell *drvr_cell,
+                    const Pvt *pvt,
+                    const GateTableModel *gate_model,
+                    const RiseFall *rf,
+                    double rd,
+                    double in_slew,
+                    double c2,
+                    double rpi,
+                    double c1);
+  virtual std::pair<double, double> gateDelaySlew() = 0;
+  virtual std::pair<double, double> loadDelaySlew(const Pin *load_pin,
+                                                  double elmore);
+  double ceff() { return ceff_; }
+
+  // Given x_ as a vector of input parameters, fill fvec_ with the
+  // equations evaluated at x_ and fjac_ with the jabobian evaluated at x_.
+  virtual void evalDmpEqns() = 0;
+  // Output response to vs(t) ramp driving pi model load (vo, dvo_dt).
+  std::pair<double, double> Vo(double t);
+  // Load response to driver waveform (vl, dvl/dt).
+  std::pair<double, double> Vl(double t);
+
+protected:
+  void luDecomp();
+  void luSolve();
+  void newtonRaphson();
+  // Find driver parameters t0, delta_t, Ceff.
+  void findDriverParams(double ceff);
+  std::pair<double, double> gateCapDelaySlew(double ceff);
+  std::tuple<double, double, double> gateDelays(double ceff);
+  // Partial derivatives of y(t) jacobian (dydt0, dyddt, dydcl).
+  std::tuple<double, double, double> dy(double t,
+                                        double t0,
+                                        double dt,
+                                        double cl);
+  double y0dt(double t,
+              double cl);
+  double y0dcl(double t,
+               double cl);
+  void showX();
+  void showFvec();
+  void showJacobian();
+  std::pair<double, double> findDriverDelaySlew();
+  double findVoCrossing(double vth,
+                        double t_lower,
+                        double t_upper);
+  void showVo();
+  double findVlCrossing(double vth,
+                        double t_lower,
+                        double t_upper);
+  void showVl();
+  void fail(std::string_view reason);
+
+  // Output response to vs(t) ramp driving capacitive load (y, t1).
+  std::pair<double, double> y(double t,
+                              double t0,
+                              double dt,
+                              double cl);
+  // Output response to unit ramp driving capacitive load.
+  double y0(double t,
+            double cl);
+  // Output response to unit ramp driving pi model load.
+  // Unit ramp output at pi load (vo, dvo_dt).
+  virtual std::pair<double, double> V0(double t) = 0;
+  // Upper bound on time that vo crosses vh.
+  virtual double voCrossingUpperBound() = 0;
+  // Load responce to driver unit ramp.
+  // Unit ramp load response (vl, dvl_dt).
+  virtual std::pair<double, double> Vl0(double t) = 0;
+  // Upper bound on time that vl crosses vh.
+  double vlCrossingUpperBound();
+
+  // Inputs to the delay calculator.
+  const LibertyCell *drvr_cell_;
+  const LibertyLibrary *drvr_library_;
+  const Pvt *pvt_;
+  const GateTableModel *gate_model_;
+  double in_slew_;
+  double c2_{0.0};
+  double rpi_{0.0};
+  double c1_{0.0};
+
+  double rd_;
+  // Logic threshold (percentage of supply voltage).
+  double vth_;
+  // Slew lower limit (percentage of supply voltage).
+  double vl_;
+  // Slew upper limit (percentage of supply voltage).
+  double vh_;
+  // Table slews are scaled by slew_derate to get
+  // measured slews from vl to vh.
+  double slew_derate_;
+
+  // Driver parameters calculated by this algorithm.
+  double t0_;
+  double dt_;
+  double ceff_;
+
+  // Driver parameter Newton-Raphson state.
+  int nr_order_;
+
+  static constexpr int max_nr_order_ = 3;
+
+  std::array<double, max_nr_order_> x_;
+  std::array<double, max_nr_order_> fvec_;
+  std::array<std::array<double, max_nr_order_>, max_nr_order_> fjac_;
+  std::array<double, max_nr_order_> scale_;
+  std::array<double, max_nr_order_> p_;
+  std::array<int, max_nr_order_> index_;
+
+  // Driver slew used to check load delay.
+  double drvr_slew_;
+  double vo_delay_;
+  // True if the driver parameters are valid for finding the load delays.
+  bool driver_valid_;
+  // Load rspf elmore delay.
+  double elmore_;
+  double p3_;
+
+  // Tolerance (as a scale of value) for driver parameters (Ceff, delta t, t0).
+  static constexpr double driver_param_tol_ = .01;
+  // Waveform threshold crossing time tolerance (1.0 = 100%).
+  static constexpr double vth_time_tol_ = .01;
+  // Max iterations for findRoot.
+  static constexpr int find_root_max_iter_ = 20;
+  static inline int newton_raphson_max_iter_ = 100;
+  // A small number used by luDecomp.
+  static constexpr double tiny_double_ = 1.0e-20;
+};
+
+// Capacitive load.
+class DmpCap : public DmpAlg
+{
+public:
+  DmpCap(StaState *sta);
+  std::string_view name() override { return "cap"; }
+  void init(const LibertyLibrary *library,
+            const LibertyCell *drvr_cell,
+            const Pvt *pvt,
+            const GateTableModel *gate_model,
+            const RiseFall *rf,
+            double rd,
+            double in_slew,
+            double c2,
+            double rpi,
+            double c1) override;
+  std::pair<double, double> gateDelaySlew() override;
+  std::pair<double, double> loadDelaySlew(const Pin *,
+                                           double elmore) override;
+  void evalDmpEqns() override;
+
+protected:
+  double voCrossingUpperBound() override;
+  std::pair<double, double> V0(double t) override;
+  std::pair<double, double> Vl0(double t) override;
+};
+
+// No non-zero pi model parameters, two poles, one zero
+class DmpPi : public DmpAlg
+{
+public:
+  DmpPi(StaState *sta);
+  std::string_view name() override { return "Pi"; }
+  void init(const LibertyLibrary *library,
+            const LibertyCell *drvr_cell,
+            const Pvt *pvt,
+            const GateTableModel *gate_model,
+            const RiseFall *rf,
+            double rd,
+            double in_slew,
+            double c2,
+            double rpi,
+            double c1) override;
+  std::pair<double, double> gateDelaySlew() override;
+  void evalDmpEqns() override;
+
+protected:
+  double voCrossingUpperBound() override;
+  std::pair<double, double> V0(double t) override;
+  std::pair<double, double> Vl0(double t) override;
+
+private:
+  void findDriverParamsPi();
+  double ipiIceff(double t0,
+                  double dt,
+                  double ceff_time,
+                  double ceff);
+
+  // Poles/zero.
+  double p1_{0.0};
+  double p2_{0.0};
+  double z1_{0.0};
+  // Residues.
+  double k0_{0.0};
+  double k1_{0.0};
+  double k2_{0.0};
+  double k3_{0.0};
+  double k4_{0.0};
+  // Ipi coefficients.
+  double A_{0.0};
+  double B_{0.0};
+  double D_{0.0};
+};
+
+// Capacitive load, so Ceff is known.
+// Solve for t0, delta t.
+class DmpOnePole : public DmpAlg
+{
+public:
+  DmpOnePole(StaState *sta);
+  void evalDmpEqns() override;
+
+protected:
+  double voCrossingUpperBound() override;
+};
+
+// C2 = 0, one pole, one zero.
+class DmpZeroC2 : public DmpOnePole
+{
+public:
+  DmpZeroC2(StaState *sta);
+  std::string_view name() override { return "c2=0"; }
+  void init(const LibertyLibrary *drvr_library,
+            const LibertyCell *drvr_cell,
+            const Pvt *pvt,
+            const GateTableModel *gate_model,
+            const RiseFall *rf,
+            double rd,
+            double in_slew,
+            double c2,
+            double rpi,
+            double c1) override;
+  std::pair<double, double> gateDelaySlew() override;
+
+protected:
+  std::pair<double, double> V0(double t) override;
+  std::pair<double, double> Vl0(double t) override;
+  double voCrossingUpperBound() override;
+
+private:
+  // Pole/zero.
+  double p1_{0.0};
+  double z1_{0.0};
+  // Residues.
+  double k0_{0.0};
+  double k1_{0.0};
+  double k2_{0.0};
+  double k3_{0.0};
+};
+
 // Delay calculator using Dartu/Menezes/Pileggi effective capacitance
 // algorithm for RSPF loads.
 class DmpCeffDelayCalc : public LumpedCapDelayCalc
 {
 public:
   DmpCeffDelayCalc(StaState *sta);
-  ~DmpCeffDelayCalc() override;
   bool reduceSupported() const override { return true; }
   ArcDcalcResult gateDelay(const Pin *drvr_pin,
                            const TimingArc *arc,
@@ -94,10 +350,9 @@ protected:
 
 private:
   // Dmp algorithms for each special pi model case.
-  // These objects are reused to minimize make/deletes.
-  DmpCap *dmp_cap_;
-  DmpPi *dmp_pi_;
-  DmpZeroC2 *dmp_zero_c2_;
+  DmpCap dmp_cap_;
+  DmpPi dmp_pi_;
+  DmpZeroC2 dmp_zero_c2_;
   DmpAlg *dmp_alg_{nullptr};
 };
 
diff --git a/dcalc/DmpDelayCalc.cc b/dcalc/DmpDelayCalc.cc
index f94d2086..03fbe83e 100644
--- a/dcalc/DmpDelayCalc.cc
+++ b/dcalc/DmpDelayCalc.cc
@@ -77,7 +77,7 @@ DmpCeffElmoreDelayCalc::DmpCeffElmoreDelayCalc(StaState *sta) :
 ArcDelayCalc *
 DmpCeffElmoreDelayCalc::copy()
 {
-  return new DmpCeffElmoreDelayCalc(this);
+  return new DmpCeffElmoreDelayCalc(*this);
 }
 
 ArcDcalcResult
@@ -213,7 +213,7 @@ DmpCeffTwoPoleDelayCalc::DmpCeffTwoPoleDelayCalc(StaState *sta) :
 ArcDelayCalc *
 DmpCeffTwoPoleDelayCalc::copy()
 {
-  return new DmpCeffTwoPoleDelayCalc(this);
+  return new DmpCeffTwoPoleDelayCalc(*this);
 }
 
 Parasitic *
diff --git a/dcalc/GraphDelayCalc.cc b/dcalc/GraphDelayCalc.cc
index 741353bf..3bf51343 100644
--- a/dcalc/GraphDelayCalc.cc
+++ b/dcalc/GraphDelayCalc.cc
@@ -292,6 +292,7 @@ class FindVertexDelays : public VertexVisitor
 {
 public:
   FindVertexDelays(GraphDelayCalc *graph_delay_calc1);
+  FindVertexDelays(const FindVertexDelays &find_vertex_delays);
   ~FindVertexDelays() override;
   void visit(Vertex *vertex) override;
   VertexVisitor *copy() const override;
@@ -308,6 +309,11 @@ FindVertexDelays::FindVertexDelays(GraphDelayCalc *graph_delay_calc) :
 {
 }
 
+FindVertexDelays::FindVertexDelays(const FindVertexDelays &find_vertex_delays) :
+  FindVertexDelays(find_vertex_delays.graph_delay_calc_)
+{
+}
+
 FindVertexDelays::~FindVertexDelays()
 {
   delete arc_delay_calc_;
@@ -318,7 +324,7 @@ FindVertexDelays::copy() const
 {
   // Copy StaState::arc_delay_calc_ because it needs separate state
   // for each thread.
-  return new FindVertexDelays(graph_delay_calc_);
+  return new FindVertexDelays(*this);
 }
 
 void
diff --git a/dcalc/LumpedCapDelayCalc.cc b/dcalc/LumpedCapDelayCalc.cc
index 41ef4250..3e8c989b 100644
--- a/dcalc/LumpedCapDelayCalc.cc
+++ b/dcalc/LumpedCapDelayCalc.cc
@@ -54,7 +54,7 @@ LumpedCapDelayCalc::LumpedCapDelayCalc(StaState *sta) :
 ArcDelayCalc *
 LumpedCapDelayCalc::copy()
 {
-  return new LumpedCapDelayCalc(this);
+  return new LumpedCapDelayCalc(*this);
 }
 
 Parasitic *
diff --git a/dcalc/UnitDelayCalc.cc b/dcalc/UnitDelayCalc.cc
index f376ec7b..8f3d9cc8 100644
--- a/dcalc/UnitDelayCalc.cc
+++ b/dcalc/UnitDelayCalc.cc
@@ -42,7 +42,7 @@ UnitDelayCalc::UnitDelayCalc(StaState *sta) :
 ArcDelayCalc *
 UnitDelayCalc::copy()
 {
-  return new UnitDelayCalc(this);
+  return new UnitDelayCalc(*this);
 }
 
 Parasitic *
diff --git a/doc/ChangeLog.txt b/doc/ChangeLog.txt
index b6238246..f4ab5751 100644
--- a/doc/ChangeLog.txt
+++ b/doc/ChangeLog.txt
@@ -4,6 +4,13 @@ OpenSTA Timing Analyzer Release Notes
 This file summarizes user visible changes for each release.
 See ApiChangeLog.txt for changes to the STA api.
 
+2026/05/01
+----------
+
+The write_sdc command supports a -mode argument.
+
+  write_sdc [-mode mode]
+
 2026/03/23
 ----------
 
diff --git a/include/sta/BoundedHeap.hh b/include/sta/BoundedHeap.hh
index 6ae23ce0..eaebc9ef 100644
--- a/include/sta/BoundedHeap.hh
+++ b/include/sta/BoundedHeap.hh
@@ -63,7 +63,6 @@ public:
   {
   }
 
-  // Copy constructor
   BoundedHeap(const BoundedHeap& other) :
     heap_(other.heap_),
     max_size_(other.max_size_),
diff --git a/include/sta/Graph.hh b/include/sta/Graph.hh
index 233d363c..a3553048 100644
--- a/include/sta/Graph.hh
+++ b/include/sta/Graph.hh
@@ -327,7 +327,7 @@ protected:
   bool has_downstream_clk_pin_:1;
   bool visited1_:1;
   bool visited2_:1;
-  bool has_sim_value_;
+  bool has_sim_value_:1;
 
 private:
   friend class Graph;
diff --git a/include/sta/Property.hh b/include/sta/Property.hh
index adeee3cc..1bb1e149 100644
--- a/include/sta/Property.hh
+++ b/include/sta/Property.hh
@@ -199,9 +199,7 @@ public:
   PropertyValue(ClockSet *value);
   PropertyValue(ConstPathSeq *value);
   PropertyValue(PwrActivity *value);
-  // Copy constructor.
   PropertyValue(const PropertyValue &value);
-  // Move constructor.
   PropertyValue(PropertyValue &&value) noexcept;
   ~PropertyValue();
   Type type() const { return type_; }
diff --git a/include/sta/Search.hh b/include/sta/Search.hh
index 58506e1f..841dbe6b 100644
--- a/include/sta/Search.hh
+++ b/include/sta/Search.hh
@@ -738,15 +738,15 @@ protected:
                          Vertex *to_vertex);
   // Return false to stop visiting.
   [[nodiscard]] bool visitArc(const Pin *from_pin,
-                               Vertex *from_vertex,
-                               const RiseFall *from_rf,
-                               Path *from_path,
-                               Edge *edge,
-                               TimingArc *arc,
-                const Pin *to_pin,
-                Vertex *to_vertex,
-                const MinMax *min_max,
-                const Mode *mode);
+                              Vertex *from_vertex,
+                              const RiseFall *from_rf,
+                              Path *from_path,
+                              Edge *edge,
+                              TimingArc *arc,
+                              const Pin *to_pin,
+                              Vertex *to_vertex,
+                              const MinMax *min_max,
+                              const Mode *mode);
   // This calls visit below with everything required to make to_path.
   // Return false to stop visiting.
   virtual bool visitFromPath(const Pin *from_pin,
@@ -770,6 +770,7 @@ class ArrivalVisitor : public PathVisitor
 {
 public:
   ArrivalVisitor(const StaState *sta);
+  ArrivalVisitor(const ArrivalVisitor &arrival_visitor);
   ~ArrivalVisitor() override;
   // Initialize the visitor.
   void init(bool always_to_endpoints,
@@ -797,9 +798,6 @@ public:
   TagGroupBldr *tagBldr() const { return tag_bldr_; }
 
 protected:
-  ArrivalVisitor(bool always_to_endpoints,
-                 SearchPred *pred,
-                 const StaState *sta);
   void init0();
   void enqueueRefPinInputDelays(const Pin *ref_pin,
                                 const Sdc *sdc);
@@ -842,6 +840,7 @@ class RequiredVisitor : public PathVisitor
 {
 public:
   RequiredVisitor(const StaState *sta);
+  RequiredVisitor(const RequiredVisitor &required_visitor);
   ~RequiredVisitor() override;
   VertexVisitor *copy() const override;
   void visit(Vertex *vertex) override;
@@ -862,10 +861,7 @@ public:
                        const MinMax *min_max) override;
 
 protected:
-  RequiredVisitor(bool make_tag_cache,
-                  const StaState *sta);
-
-  RequiredCmp *required_cmp_;
+  RequiredCmp required_cmp_;
   VisitPathEnds *visit_path_ends_;
 };
 
diff --git a/include/sta/Sta.hh b/include/sta/Sta.hh
index 36bfa0d7..561ce3aa 100644
--- a/include/sta/Sta.hh
+++ b/include/sta/Sta.hh
@@ -138,7 +138,7 @@ public:
   void setCmdScene(Scene *scene);
   SceneSeq makeSceneSeq(Scene *scene) const;
 
-  Mode *cmdMode() const { return cmd_scene_->mode(); }
+  Mode *cmdMode() const { return cmd_mode_; }
   const std::string &cmdModeName();
   void setCmdMode(std::string_view mode_name);
   Mode *findMode(std::string_view mode_name) const;
@@ -1042,6 +1042,13 @@ public:
                               const Scene *scene,
                               const MinMax *min_max,
                               int digits);
+  void writeSdc(std::string_view filename,
+                std::string_view mode_name,
+                bool leaf,
+                bool native,
+                int digits,
+                bool gzip,
+                bool no_timestamp);
   void writeSdc(const Sdc *sdc,
                 std::string_view filename,
                 // Map hierarchical pins and instances to leaf pins and instances.
@@ -1610,6 +1617,7 @@ protected:
   void checkLibrarayPocv();
 
   Scene *cmd_scene_{nullptr};
+  Mode *cmd_mode_{nullptr};
   CmdNamespace cmd_namespace_{CmdNamespace::sdc};
   Instance *current_instance_{nullptr};
   SceneNameMap scene_name_map_;
diff --git a/power/Power.cc b/power/Power.cc
index f5333f62..c5075522 100644
--- a/power/Power.cc
+++ b/power/Power.cc
@@ -575,6 +575,7 @@ public:
   PropActivityVisitor(Power *power,
                       const Mode *mode,
                       BfsFwdIterator *bfs);
+  PropActivityVisitor(const PropActivityVisitor &visitor);
   VertexVisitor *copy() const override;
   void visit(Vertex *vertex) override;
   InstanceSet &visitedRegs() { return visited_regs_; }
@@ -606,10 +607,15 @@ PropActivityVisitor::PropActivityVisitor(Power *power,
 {
 }
 
+PropActivityVisitor::PropActivityVisitor(const PropActivityVisitor &visitor) :
+  PropActivityVisitor(visitor.power_, visitor.mode_, visitor.bfs_)
+{
+}
+
 VertexVisitor *
 PropActivityVisitor::copy() const
 {
-  return new PropActivityVisitor(power_, mode_, bfs_);
+  return new PropActivityVisitor(*this);
 }
 
 void
diff --git a/sdc/Sdc.i b/sdc/Sdc.i
index 0a02cb07..4b3050b0 100644
--- a/sdc/Sdc.i
+++ b/sdc/Sdc.i
@@ -94,15 +94,15 @@ private:
 
 void
 write_sdc_cmd(std::string filename,
-             bool leaf,
-             bool compatible,
-             int digits,
-             bool gzip,
-             bool no_timestamp)
+              std::string mode_name,
+              bool leaf,
+              bool compatible,
+              int digits,
+              bool gzip,
+              bool no_timestamp)
 {
   Sta *sta = Sta::sta();
-  const Sdc *sdc = sta->cmdSdc();
-  sta->writeSdc(sdc, filename, leaf, compatible, digits, gzip, no_timestamp);
+  sta->writeSdc(filename, mode_name, leaf, compatible, digits, gzip, no_timestamp);
 }
 
 void
diff --git a/sdc/Sdc.tcl b/sdc/Sdc.tcl
index d8e5aef1..5588c8f1 100644
--- a/sdc/Sdc.tcl
+++ b/sdc/Sdc.tcl
@@ -42,31 +42,38 @@ proc_redirect read_sdc {
   check_argc_eq1 "read_sdc" $args
   set echo [info exists flags(-echo)]
   set filename [file nativename [lindex $args 0]]
-  set mode_name {}
+
   if { [info exists keys(-mode)] } {
     set mode_name $keys(-mode)
-  }
-  set prev_mode [cmd_mode_name]
-  try {
-    set_mode_cmd $mode_name
-    include_file $filename $echo 0
-  } finally {
-    if { $prev_mode != "default" } {
-      set_mode_cmd $prev_mode
+    set prev_mode [cmd_mode]
+    try {
+      set_cmd_mode $mode_name
+      include_file $filename $echo 0
+    } finally {
+      if { $prev_mode != "default" } {
+        set_cmd_mode $prev_mode
+      }
     }
+  } else {
+    include_file $filename $echo 0
   }
 }
 
 ################################################################
 
 define_cmd_args "write_sdc" \
-  {[-map_hpins] [-digits digits] [-gzip] [-no_timestamp] filename}
+  {[-mode mode] [-map_hpins] [-digits digits] [-gzip] [-no_timestamp] filename}
 
 proc write_sdc { args } {
-  parse_key_args "write_sdc" args keys {-digits -significant_digits} \
+  parse_key_args "write_sdc" args keys {-mode -digits} \
     flags {-map_hpins -compatible -gzip -no_timestamp}
   check_argc_eq1 "write_sdc" $args
 
+  set mode [cmd_mode]
+  if { [info exists keys(-mode)] } {
+    set mode $keys(-mode)
+  }
+  
   set digits 4
   if { [info exists keys(-digits)] } {
     set digits $keys(-digits)
@@ -78,7 +85,7 @@ proc write_sdc { args } {
   set no_timestamp [info exists flags(-no_timestamp)]
   set map_hpins [info exists flags(-map_hpins)]
   set native [expr ![info exists flags(-compatible)]]
-  write_sdc_cmd $filename $map_hpins $native $digits $gzip $no_timestamp
+  write_sdc_cmd $filename $mode $map_hpins $native $digits $gzip $no_timestamp
 }
 
 ################################################################
diff --git a/tcl/Variables.tcl b/sdc/Variables.tcl
similarity index 100%
rename from tcl/Variables.tcl
rename to sdc/Variables.tcl
diff --git a/sdf/Sdf.tcl b/sdf/Sdf.tcl
index df0a775c..bdbb1de8 100644
--- a/sdf/Sdf.tcl
+++ b/sdf/Sdf.tcl
@@ -180,7 +180,7 @@ define_cmd_args "write_sdf" \
 
 proc_redirect write_sdf {
   parse_key_args "write_sdf" args \
-    keys {-corner -scene -divider -digits -significant_digits} \
+    keys {-corner -scene -divider -digits} \
     flags {-include_typ -gzip -no_timestamp -no_version}
   check_argc_eq1 "write_sdf" $args
   set scene [parse_scene keys]
diff --git a/search/GatedClk.cc b/search/GatedClk.cc
index 11880d02..ad79dbdb 100644
--- a/search/GatedClk.cc
+++ b/search/GatedClk.cc
@@ -107,7 +107,6 @@ GatedClk::isGatedClkEnable(Vertex *enable_vertex,
         }
       }
     }
-    
   }
 }
 
diff --git a/search/Genclks.cc b/search/Genclks.cc
index 2123ea1b..851a601a 100644
--- a/search/Genclks.cc
+++ b/search/Genclks.cc
@@ -693,17 +693,11 @@ public:
                           BfsFwdIterator *insert_iter,
                           GenclkInfo *genclk_info,
                           const Mode *mode);
+  GenclkSrcArrivalVisitor(const GenclkSrcArrivalVisitor &visitor);
   VertexVisitor *copy() const override;
   void visit(Vertex *vertex) override;
 
 protected:
-  GenclkSrcArrivalVisitor(Clock *gclk,
-                          BfsFwdIterator *insert_iter,
-                          GenclkInfo *genclk_info,
-                          bool always_to_endpoints,
-                          SearchPred *pred,
-                          const Mode *mode);
-
   Clock *gclk_;
   BfsFwdIterator *insert_iter_;
   GenclkInfo *genclk_info_;
@@ -728,29 +722,22 @@ GenclkSrcArrivalVisitor::GenclkSrcArrivalVisitor(Clock *gclk,
 {
 }
 
-// Copy constructor.
-GenclkSrcArrivalVisitor::GenclkSrcArrivalVisitor(Clock *gclk,
-                                                 BfsFwdIterator *insert_iter,
-                                                 GenclkInfo *genclk_info,
-                                                 bool always_to_endpoints,
-                                                 SearchPred *pred,
-                                                 const Mode *mode) :
-  ArrivalVisitor(always_to_endpoints, pred, this),
-  gclk_(gclk),
-  insert_iter_(insert_iter),
-  genclk_info_(genclk_info),
-  srch_pred_(gclk, genclk_info, this),
-  mode_(mode),
-  sdc_(mode->sdc()),
-  genclks_(mode->genclks())
+GenclkSrcArrivalVisitor::GenclkSrcArrivalVisitor(const GenclkSrcArrivalVisitor &visitor) :
+  ArrivalVisitor(visitor),
+  gclk_(visitor.gclk_),
+  insert_iter_(visitor.insert_iter_),
+  genclk_info_(visitor.genclk_info_),
+  srch_pred_(visitor.gclk_, visitor.genclk_info_, this),
+  mode_(visitor.mode_),
+  sdc_(visitor.sdc_),
+  genclks_(visitor.genclks_)
 {
 }
 
 VertexVisitor *
 GenclkSrcArrivalVisitor::copy() const
 {
-  return new GenclkSrcArrivalVisitor(gclk_, insert_iter_, genclk_info_,
-                                     always_to_endpoints_, pred_, mode_);
+  return new GenclkSrcArrivalVisitor(*this);
 }
 
 void
diff --git a/search/PathEnum.cc b/search/PathEnum.cc
index c285b8f9..7c65f26e 100644
--- a/search/PathEnum.cc
+++ b/search/PathEnum.cc
@@ -246,6 +246,7 @@ public:
                        bool unique_pins,
                        bool unique_edges,
                        PathEnum *path_enum);
+  PathEnumFaninVisitor(const PathEnumFaninVisitor &visitor);
   VertexVisitor *copy() const override;
   void visitFaninPathsThru(Path *before_div,
                            Vertex *prev_vertex,
@@ -327,11 +328,16 @@ PathEnumFaninVisitor::PathEnumFaninVisitor(PathEnd *path_end,
 {
 }
 
+PathEnumFaninVisitor::PathEnumFaninVisitor(const PathEnumFaninVisitor &visitor) :
+  PathEnumFaninVisitor(visitor.path_end_, visitor.before_div_, visitor.unique_pins_,
+                       visitor.unique_edges_, visitor.path_enum_)
+{
+}
+
 VertexVisitor *
 PathEnumFaninVisitor::copy() const
 {
-  return new PathEnumFaninVisitor(path_end_, before_div_, unique_pins_,
-                                  unique_edges_, path_enum_);
+  return new PathEnumFaninVisitor(*this);
 }
 
 void
diff --git a/search/PathGroup.cc b/search/PathGroup.cc
index 6750613c..725b52c7 100644
--- a/search/PathGroup.cc
+++ b/search/PathGroup.cc
@@ -995,7 +995,7 @@ MakeEndpointPathEnds::~MakeEndpointPathEnds()
 VertexVisitor *
 MakeEndpointPathEnds::copy() const
 {
-  return new MakeEndpointPathEnds(path_end_visitor_, scenes_, min_max_, sta_);
+  return new MakeEndpointPathEnds(*this);
 }
 
 void
diff --git a/search/Search.cc b/search/Search.cc
index 081daac8..ee735a0c 100644
--- a/search/Search.cc
+++ b/search/Search.cc
@@ -1090,14 +1090,11 @@ ArrivalVisitor::ArrivalVisitor(const StaState *sta) :
   init(true, false, nullptr);
 }
 
-// Copy constructor.
-ArrivalVisitor::ArrivalVisitor(bool always_to_endpoints,
-                               SearchPred *pred,
-                               const StaState *sta) :
-  PathVisitor(pred, true, sta)
+ArrivalVisitor::ArrivalVisitor(const ArrivalVisitor &arrival_visitor) :
+  PathVisitor(arrival_visitor.pred_, true, &arrival_visitor)
 {
   init0();
-  init(always_to_endpoints, false, pred);
+  init(arrival_visitor.always_to_endpoints_, false, arrival_visitor.pred_);
 }
 
 void
@@ -1122,7 +1119,7 @@ ArrivalVisitor::init(bool always_to_endpoints,
 VertexVisitor *
 ArrivalVisitor::copy() const
 {
-  return new ArrivalVisitor(always_to_endpoints_, pred_, this);
+  return new ArrivalVisitor(*this);
 }
 
 void
@@ -1966,7 +1963,10 @@ PathVisitor::PathVisitor(SearchPred *pred,
 {
 }
 
-PathVisitor::~PathVisitor() { delete tag_cache_; }
+PathVisitor::~PathVisitor()
+{
+  delete tag_cache_;
+}
 
 void
 PathVisitor::visitFaninPaths(Vertex *to_vertex)
@@ -2775,23 +2775,19 @@ Search::reportArrivals(Vertex *vertex,
       bool report_prev = false;
       std::string prev_str;
       if (report_prev) {
-        prev_str = "prev ";
         Path *prev_path = path->prevPath();
         if (prev_path) {
-          prev_str += prev_path->to_string(this);
-          prev_str += " ";
           const Edge *prev_edge = path->prevEdge(this);
           TimingArc *arc = path->prevArc(this);
-          prev_str += prev_edge->from(graph_)->to_string(this);
-          prev_str += " ";
-          prev_str += arc->fromEdge()->to_string();
-          prev_str += " -> ";
-          prev_str += prev_edge->to(graph_)->to_string(this);
-          prev_str += " ";
-          prev_str += arc->toEdge()->to_string();
+          prev_str = sta::format("prev {} {} {} -> {} {}",
+                                 prev_path->to_string(this),
+                                 prev_edge->from(graph_)->to_string(this),
+                                 arc->fromEdge()->to_string(),
+                                 prev_edge->to(graph_)->to_string(this),
+                                 arc->toEdge()->to_string());
         }
         else
-          prev_str += "NULL";
+          prev_str = "prev NULL";
       }
       report_->report(" {} {} {} / {} {}{}", rf->shortName(),
                       path->minMax(this)->to_string(),
@@ -3297,44 +3293,28 @@ Search::seedInvalidRequireds()
 class FindEndRequiredVisitor : public PathEndVisitor
 {
 public:
-  FindEndRequiredVisitor(RequiredCmp *required_cmp,
+  FindEndRequiredVisitor(RequiredCmp &required_cmp,
                          const StaState *sta);
   FindEndRequiredVisitor(const StaState *sta);
-  ~FindEndRequiredVisitor() override;
   PathEndVisitor *copy() const override;
   void visit(PathEnd *path_end) override;
 
 protected:
   const StaState *sta_;
-  RequiredCmp *required_cmp_;
-  bool own_required_cmp_;
+  RequiredCmp &required_cmp_;
 };
 
-FindEndRequiredVisitor::FindEndRequiredVisitor(RequiredCmp *required_cmp,
+FindEndRequiredVisitor::FindEndRequiredVisitor(RequiredCmp &required_cmp,
                                                const StaState *sta) :
   sta_(sta),
-  required_cmp_(required_cmp),
-  own_required_cmp_(false)
+  required_cmp_(required_cmp)
 {
 }
 
-FindEndRequiredVisitor::FindEndRequiredVisitor(const StaState *sta) :
-  sta_(sta),
-  required_cmp_(new RequiredCmp),
-  own_required_cmp_(true)
-{
-}
-
-FindEndRequiredVisitor::~FindEndRequiredVisitor()
-{
-  if (own_required_cmp_)
-    delete required_cmp_;
-}
-
 PathEndVisitor *
 FindEndRequiredVisitor::copy() const
 {
-  return new FindEndRequiredVisitor(sta_);
+  return new FindEndRequiredVisitor(*this);
 }
 
 void
@@ -3345,7 +3325,7 @@ FindEndRequiredVisitor::visit(PathEnd *path_end)
     const MinMax *min_max = path->minMax(sta_)->opposite();
     size_t path_index = path->pathIndex(sta_);
     Required required = path_end->requiredTime(sta_);
-    required_cmp_->requiredSet(path_index, required, min_max, sta_);
+    required_cmp_.requiredSet(path_index, required, min_max, sta_);
   }
 }
 
@@ -3355,7 +3335,7 @@ Search::seedRequired(Vertex *vertex)
   debugPrint(debug_, "search", 2, "required seed {}",
              vertex->to_string(this));
   RequiredCmp required_cmp;
-  FindEndRequiredVisitor seeder(&required_cmp, this);
+  FindEndRequiredVisitor seeder(required_cmp, this);
   required_cmp.requiredsInit(vertex, this);
   visit_path_ends_->visitPathEnds(vertex, &seeder);
   // Enqueue fanin vertices for back-propagating required times.
@@ -3367,7 +3347,7 @@ void
 Search::seedRequiredEnqueueFanin(Vertex *vertex)
 {
   RequiredCmp required_cmp;
-  FindEndRequiredVisitor seeder(&required_cmp, this);
+  FindEndRequiredVisitor seeder(required_cmp, this);
   required_cmp.requiredsInit(vertex, this);
   visit_path_ends_->visitPathEnds(vertex, &seeder);
   // Enqueue fanin vertices for back-propagating required times.
@@ -3442,31 +3422,25 @@ RequiredCmp::required(size_t path_index)
 
 RequiredVisitor::RequiredVisitor(const StaState *sta) :
   PathVisitor(sta),
-  required_cmp_(new RequiredCmp),
   visit_path_ends_(new VisitPathEnds(sta))
 {
 }
 
-RequiredVisitor::RequiredVisitor(bool make_tag_cache,
-                                 const StaState *sta) :
-  PathVisitor(sta->search()->evalPred(),
-              make_tag_cache,
-              sta),
-  required_cmp_(new RequiredCmp),
-  visit_path_ends_(new VisitPathEnds(sta))
+RequiredVisitor::RequiredVisitor(const RequiredVisitor &required_visitor) :
+  PathVisitor(required_visitor.search()->evalPred(), true, &required_visitor),
+  visit_path_ends_(new VisitPathEnds(&required_visitor))
 {
 }
 
 RequiredVisitor::~RequiredVisitor()
 {
-  delete required_cmp_;
   delete visit_path_ends_;
 }
 
 VertexVisitor *
 RequiredVisitor::copy() const
 {
-  return new RequiredVisitor(true, this);
+  return new RequiredVisitor(*this);
 }
 
 void
@@ -3474,7 +3448,7 @@ RequiredVisitor::visit(Vertex *vertex)
 {
   debugPrint(debug_, "search", 2, "find required {}",
              vertex->to_string(this));
-  required_cmp_->requiredsInit(vertex, this);
+  required_cmp_.requiredsInit(vertex, this);
   // Back propagate requireds from fanout.
   visitFanoutPaths(vertex);
   // Check for constraints at endpoints that set required times.
@@ -3482,7 +3456,7 @@ RequiredVisitor::visit(Vertex *vertex)
     FindEndRequiredVisitor seeder(required_cmp_, this);
     visit_path_ends_->visitPathEnds(vertex, &seeder);
   }
-  bool changed = required_cmp_->requiredsSave(vertex, this);
+  bool changed = required_cmp_.requiredsSave(vertex, this);
   search_->tnsInvalid(vertex);
 
   if (changed)
@@ -3528,8 +3502,8 @@ RequiredVisitor::visitFromToPath(const Pin *,
                  delayAsString(arc_delay, this),
                  delayAsString(from_required, this),
                  min_max == MinMax::max() ? "<" : ">",
-                 delayAsString(required_cmp_->required(path_index), this));
-      required_cmp_->requiredSet(path_index, from_required, req_min, this);
+                 delayAsString(required_cmp_.required(path_index), this));
+      required_cmp_.requiredSet(path_index, from_required, req_min, this);
     }
     else {
       if (search_->crprApproxMissingRequireds()) {
@@ -3552,8 +3526,8 @@ RequiredVisitor::visitFromToPath(const Pin *,
                        delayAsString(arc_delay, this),
                        delayAsString(from_required, this),
                        min_max == MinMax::max() ? "<" : ">",
-                       delayAsString(required_cmp_->required(path_index), this));
-            required_cmp_->requiredSet(path_index, from_required, req_min, this);
+                       delayAsString(required_cmp_.required(path_index), this));
+            required_cmp_.requiredSet(path_index, from_required, req_min, this);
             break;
           }
         }
diff --git a/search/Search.i b/search/Search.i
index 3a6f1b31..62b48564 100644
--- a/search/Search.i
+++ b/search/Search.i
@@ -113,6 +113,7 @@ void
 clear_network()
 {
   Sta *sta = Sta::sta();
+  sta->clear();
   sta->network()->clear();
 }
 
@@ -818,8 +819,14 @@ cmd_mode_name()
   return Sta::sta()->cmdMode()->name();
 }
 
+Mode *
+cmd_mode()
+{
+  return Sta::sta()->cmdMode();
+}
+
 void
-set_mode_cmd(std::string mode_name)
+set_cmd_mode(std::string mode_name)
 {
   Sta::sta()->setCmdMode(mode_name);
 }
@@ -830,6 +837,12 @@ find_modes(std::string mode_name)
   return Sta::sta()->findModes(mode_name);
 }
 
+Mode *
+find_mode(std::string mode_name)
+{
+  return Sta::sta()->findMode(mode_name);
+}
+
 ////////////////////////////////////////////////////////////////
 
 CheckErrorSeq &
diff --git a/search/Sta.cc b/search/Sta.cc
index 4c29e355..990ecc9a 100644
--- a/search/Sta.cc
+++ b/search/Sta.cc
@@ -570,30 +570,46 @@ Sta::clearNonSdc()
 Sdc *
 Sta::cmdSdc() const
 {
-  return cmdMode()->sdc();
+  return cmd_mode_->sdc();
 }
 
 void
 Sta::setCmdMode(std::string_view mode_name)
 {
-  if (!mode_name.empty()) {
-    if (!mode_name_map_.contains(mode_name)) {
-      if (modes_.size() == 1 && modes_[0]->name() == "default") {
-        // No need for default mode if one is defined.
-        delete modes_[0];
-        mode_name_map_.clear();
-        modes_.clear();
+  Mode *mode = findKey(mode_name_map_, std::string(mode_name));
+  if (mode) {
+    // Sync scene with mode. Note that multiple scenes can share a mode.
+    Scene *mode_scene = nullptr;
+    for (Scene *scene : scenes_) {
+      if (scene->mode() == mode) {
+        if (mode_scene) {
+          report_->warn(1556, "multiple scenes reference mode {}", mode_name);
+          break;
+        }
+        mode_scene = scene;
       }
-      Mode *mode = new Mode(mode_name, mode_name_map_.size(), this);
-      mode_name_map_[std::string(mode_name)] = mode;
-      modes_.push_back(mode);
-      mode->sim()->setMode(mode);
-      mode->sim()->setObserver(new StaSimObserver(this));
-
-      if (scenes_.size() == 1 && scenes_[0]->name() == "default")
-        scenes_[0]->setMode(mode);
-      updateComponentsState();
     }
+    if (mode_scene)
+      cmd_scene_ = mode_scene;
+    cmd_mode_ = mode;
+  }
+  else {
+    if (modes_.size() == 1 && modes_[0]->name() == "default") {
+      // No need for default mode if one is defined.
+      delete modes_[0];
+      mode_name_map_.clear();
+      modes_.clear();
+    }
+    Mode *mode = new Mode(mode_name, mode_name_map_.size(), this);
+    mode_name_map_[std::string(mode_name)] = mode;
+    modes_.push_back(mode);
+    mode->sim()->setMode(mode);
+    mode->sim()->setObserver(new StaSimObserver(this));
+    cmd_mode_ = mode;
+
+    if (scenes_.size() == 1 && scenes_[0]->name() == "default")
+      scenes_[0]->setMode(mode);
+    updateComponentsState();
   }
 }
 
@@ -2190,6 +2206,22 @@ Sta::checkExceptionToPins(ExceptionTo *to,
   }
 }
 
+void
+Sta::writeSdc(std::string_view filename,
+              std::string_view mode_name,
+              bool leaf,
+              bool native,
+              int digits,
+              bool gzip,
+              bool no_timestamp)
+{
+  Mode *mode = findMode(mode_name);
+  if (mode)
+    writeSdc(mode->sdc(), filename, leaf, native, digits, gzip, no_timestamp);
+  else
+    report_->warn(1561, "mode {} not found.", mode_name);
+}
+
 void
 Sta::writeSdc(const Sdc *sdc,
               std::string_view filename,
@@ -2514,6 +2546,7 @@ Sta::makeDefaultScene()
   makeScene(name, mode, parasitics);
 
   cmd_scene_ = scenes_[0];
+  cmd_mode_ = mode;
 }
 
 // define_corners (before read_liberty).
@@ -2603,8 +2636,8 @@ Sta::makeScene(const std::string &name,
   if (scenes_.size() == 1 && findScene("default"))
     deleteScenes();
 
-  Scene *scene =
-      new Scene(name, scenes_.size(), mode, parasitics_min, parasitics_max);
+  Scene *scene = new Scene(name, scenes_.size(), mode,
+                           parasitics_min, parasitics_max);
   scene_name_map_[name] = scene;
   scenes_.push_back(scene);
   mode->addScene(scene);
@@ -2696,6 +2729,7 @@ void
 Sta::setCmdScene(Scene *scene)
 {
   cmd_scene_ = scene;
+  cmd_mode_ = scene->mode();
 }
 
 SceneSeq
@@ -3270,7 +3304,7 @@ EndpointPathEndVisitor::EndpointPathEndVisitor(std::string_view path_group_name,
 PathEndVisitor *
 EndpointPathEndVisitor::copy() const
 {
-  return new EndpointPathEndVisitor(path_group_name_, min_max_, sta_);
+  return new EndpointPathEndVisitor(*this);
 }
 
 void
@@ -3523,7 +3557,7 @@ Sta::findRequired(Vertex *vertex)
   search_->findAllArrivals();
   if (search_->isEndpoint(vertex)
       // Need to include downstream required times if there is fanout.
-      && !hasFanout(vertex, search_->searchAdj(), graph_, cmdMode()))
+      && !hasFanout(vertex, search_->searchAdj(), graph_, cmd_mode_))
     search_->seedRequired(vertex);
   else
     search_->findRequireds(vertex->level());
@@ -3921,14 +3955,14 @@ Sta::findLogicConstants()
 {
   ensureGraph();
   // Sdc independent constants so any mode should return the same values.
-  Sim *sim = cmdMode()->sim();
+  Sim *sim = cmd_mode_->sim();
   sim->findLogicConstants();
 }
 
 void
 Sta::clearLogicConstants()
 {
-  Sim *sim = cmdMode()->sim();
+  Sim *sim = cmd_mode_->sim();
   sim->clear();
 }
 
@@ -5062,7 +5096,8 @@ Sta::clockDomains(const Pin *pin,
                   const Mode *mode)
 {
   searchPreamble();
-  search_->findAllArrivals();
+  Vertex *vertex = graph_->pinLoadVertex(pin);
+  search_->findArrivals(vertex->level());
   return search_->clockDomains(pin, mode);
 }
 
diff --git a/tcl/CmdUtil.tcl b/tcl/CmdUtil.tcl
index 74fda26f..80d9b3e0 100644
--- a/tcl/CmdUtil.tcl
+++ b/tcl/CmdUtil.tcl
@@ -191,53 +191,55 @@ proc set_unit_values { unit key suffix key_var } {
 
 ################################################################
 
-define_cmd_args "delete_from_list" {list objs}
+define_cmd_args "delete_from_list" {list delete}
 
-proc delete_from_list { list objects } {
-  delete_objects_from_list_cmd $list $objects
+proc delete_from_list { list delete } {
+  delete_objects_from_list_cmd $list $delete
 }
 
-proc delete_objects_from_list_cmd { list objects } {
-  set list0 [lindex $list 0]
-  set list_is_object [is_object $list0]
-  set list_type [object_type $list0]
-  foreach obj $objects {
-    # If the list is a collection of tcl objects (returned by get_*),
-    # convert the obj to be removed from a name to an object of the same
-    # type.
-    if {$list_is_object && ![is_object $obj]} {
-      if {$list_type == "Clock"} {
-        set obj [find_clock $obj]
-      } elseif {$list_type == "Port"} {
-        set top_instance [top_instance]
-        set top_cell [$top_instance cell]
-        set obj [$top_cell find_port $obj]
-      } elseif {$list_type == "Pin"} {
-        set obj [find_pin $obj]
-      } elseif {$list_type == "Instance"} {
-        set obj [find_instance $obj]
-      } elseif {$list_type == "Net"} {
-        set obj [find_net $obj]
-      } elseif {$list_type == "LibertyLibrary"} {
-        set obj [find_liberty $obj]
-      } elseif {$list_type == "LibertyCell"} {
-        set obj [find_liberty_cell $obj]
-      } elseif {$list_type == "LibertyPort"} {
-        set obj [get_lib_pins $obj]
-      } else {
-        sta_error 164 "unsupported object type $list_type."
+proc delete_objects_from_list_cmd { list delete } {
+  if { $list != {} } {
+    set list0 [lindex $list 0]
+    set list_is_objects [is_object $list0]
+    foreach obj $delete {
+      # If the list is a collection of tcl objects (returned by get_*),
+      # convert the obj to be removed from a name to an object of the same
+      # type.
+      if {$list_is_objects && ![is_object $obj]} {
+        set list_type [object_type $list0]
+        if {$list_type == "Clock"} {
+          set obj [find_clock $obj]
+        } elseif {$list_type == "Port"} {
+          set top_instance [top_instance]
+          set top_cell [$top_instance cell]
+          set obj [$top_cell find_port $obj]
+        } elseif {$list_type == "Pin"} {
+          set obj [find_pin $obj]
+        } elseif {$list_type == "Instance"} {
+          set obj [find_instance $obj]
+        } elseif {$list_type == "Net"} {
+          set obj [find_net $obj]
+        } elseif {$list_type == "LibertyLibrary"} {
+          set obj [find_liberty $obj]
+        } elseif {$list_type == "LibertyCell"} {
+          set obj [find_liberty_cell $obj]
+        } elseif {$list_type == "LibertyPort"} {
+          set obj [get_lib_pins $obj]
+        } else {
+          sta_error 164 "unsupported object type $list_type."
+        }
+      }
+      set index [lsearch $list $obj]
+      if { $index != -1 } {
+        set list [lreplace $list $index $index]
       }
-    }
-    set index [lsearch $list $obj]
-    if { $index != -1 } {
-      set list [lreplace $list $index $index]
     }
   }
   return $list
 }
-
+  
 ################################################################
-
+  
 proc set_cmd_namespace { namespc } {
   if { $namespc == "sdc" || $namespc == "sta" } {
     set_cmd_namespace_cmd $namespc
@@ -245,7 +247,7 @@ proc set_cmd_namespace { namespc } {
     sta_error 165 "unknown namespace $namespc."
   }
 }
-
+  
 ################################################################
 
 define_cmd_args "report_object_full_names" {objects}
@@ -295,32 +297,5 @@ proc full_name_cmp { obj1 obj2 } {
   return [string compare [get_full_name $obj1] [get_full_name $obj2]]
 }
 
-proc get_object_type { obj } {
-  set object_type [object_type $obj]
-  if { $object_type == "Clock" } {
-    return "clock"
-  } elseif { $object_type == "LibertyCell" } {
-    return "lib_cell"
-  } elseif { $object_type == "LibertyPort" } {
-    return "lib_pin"
-  } elseif { $object_type == "Cell" } {
-    return "cell"
-  } elseif { $object_type == "Instance" } {
-    return "instance"
-  } elseif { $object_type == "Port" } {
-    return "port"
-  } elseif { $object_type == "Pin" } {
-    return "pin"
-  } elseif { $object_type == "Net" } {
-    return "net"
-  } elseif { $object_type == "Edge" } {
-    return "timing_arc"
-  } elseif { $object_type == "TimingArcSet" } {
-    return "timing_arc"
-  } else {
-    return "?"
-  }
-}
-
-# sta namespace end.
+# namespace sta
 }
diff --git a/tcl/Sta.tcl b/tcl/Sta.tcl
index 2db64f5e..ee560962 100644
--- a/tcl/Sta.tcl
+++ b/tcl/Sta.tcl
@@ -102,7 +102,7 @@ define_cmd_args "set_scene" {scene_name}
 
 proc set_scene { args } {
   check_argc_eq1 "set_scene" $args
-  set_scene_cmd [lindex $args 0]
+  set_cmd_scene [lindex $args 0]
 }
 
 ################################################################
@@ -141,7 +141,7 @@ define_cmd_args "set_mode" {mode_name}
 
 proc set_mode { args } {
   check_argc_eq1 "set_mode" $args
-  set_mode_cmd [lindex $args 0]
+  set_cmd_mode [lindex $args 0]
 }
 
 ################################################################
diff --git a/tcl/StaTclTypes.i b/tcl/StaTclTypes.i
index 65a6b0f3..b002cb42 100644
--- a/tcl/StaTclTypes.i
+++ b/tcl/StaTclTypes.i
@@ -30,6 +30,9 @@
 
 %{
 
+#include <cctype>
+#include <string>
+
 #include "Network.hh"
 #include "Liberty.hh"
 #include "FuncExpr.hh"
@@ -52,7 +55,7 @@ namespace sta {
 typedef MinMaxAll MinMaxAllNull;
 
 #if TCL_MAJOR_VERSION < 9
-    typedef int Tcl_Size;
+typedef int Tcl_Size;
 #endif
 
 template <class TYPE>
@@ -256,14 +259,51 @@ setPtrTclList(SET_TYPE *set,
   Tcl_SetObjResult(interp, list);
 }
 
-////////////////////////////////////////////////////////////////
-
 } // namespace sta
 
 using namespace sta;
 
 %}
 
+////////////////////////////////////////////////////////////////
+
+%inline %{
+
+inline bool
+is_object(const char *obj)
+{
+  // _hexaddress_p_type
+  const std::string s(obj);
+  if (s.empty() || s[0] != '_')
+    return false;
+  const size_t hex_digits = sizeof(void *) * 2;
+  if (s.size() < 1 + hex_digits + 3)
+    return false;
+  for (size_t i = 1; i < 1 + hex_digits; i++) {
+    if (!std::isxdigit(static_cast<unsigned char>(s[i])))
+      return false;
+  }
+  if (s.compare(1 + hex_digits, 3, "_p_") != 0)
+    return false;
+  for (size_t i = 1 + hex_digits + 3; i < s.size(); i++) {
+    char ch = s[i];
+    if (!(std::isalnum(ch) || ch == '_'))
+      return false;
+  }
+  return true;
+}
+
+// Assumes is_object is true.
+inline const char *
+object_type(const char *obj)
+{
+  if (is_object(obj))
+    return &obj[1 + sizeof(void*) * 2 + 3];
+  return "";
+}
+
+%}
+
 ////////////////////////////////////////////////////////////////
 //
 // SWIG type definitions.
diff --git a/test/regression.tcl b/test/regression.tcl
index 3afe8287..523589be 100755
--- a/test/regression.tcl
+++ b/test/regression.tcl
@@ -156,11 +156,8 @@ proc expand_tests { argv } {
           lappend tests $test
         }
       }
-    } elseif { [lsearch [group_tests "all"] $arg] != -1 } {
-      lappend tests $arg
     } else {
-      puts "Error: test $arg not found."
-      incr errors(no_cmd)
+      lappend tests $arg
     }
   }
   return $tests
@@ -525,15 +522,11 @@ proc show_summary {} {
   if { $valgrind_shared_lib_failure } {
     puts "WARNING: valgrind failed because the executable is not statically linked."
   }
-  puts "See $result_dir for log files"
   set test_count [llength $tests]
   if { [found_errors] } {
     if { $errors(error) != 0 } {
       puts "Errored $errors(error)/$test_count"
     }
-    if { $errors(fail) != 0 } {
-      puts "Failed $errors(fail)/$test_count"
-    }
     if { $errors(leak) != 0 } {
       puts "Memory leaks in $errors(leak)/$test_count"
     }
@@ -547,7 +540,7 @@ proc show_summary {} {
       puts "No cmd tcl file for $errors(no_cmd)/$test_count"
     }
     if { $errors(fail) != 0 } {
-      puts "See $diff_file for differences"
+      puts "Failed $errors(fail)/$test_count"
     }
   } else {
     puts "Passed $test_count"
diff --git a/util/Util.i b/util/Util.i
index cb08647a..ce128f5e 100644
--- a/util/Util.i
+++ b/util/Util.i
@@ -224,37 +224,6 @@ set_debug(const char *what,
   Sta::sta()->setDebugLevel(what, level);
 }
 
-////////////////////////////////////////////////////////////////
-
-bool
-is_object(const char *obj)
-{
-  // _hexaddress_p_type
-  const char *s = obj;
-  char ch = *s++;
-  if (ch != '_')
-    return false;
-  while (*s && isxdigit(*s))
-    s++;
-  if ((s - obj - 1) == sizeof(void*) * 2
-      && *s && *s++ == '_'
-      && *s && *s++ == 'p'
-      && *s && *s++ == '_') {
-    while (*s && *s != ' ')
-      s++;
-    return *s == '\0';
-  }
-  else
-    return false;
-}
-
-// Assumes is_object is true.
-const char *
-object_type(const char *obj)
-{
-  return &obj[1 + sizeof(void*) * 2 + 3];
-}
-
 ////////////////////////////////////////////////////////////////
 //
 // Units
diff --git a/verilog/VerilogWriter.cc b/verilog/VerilogWriter.cc
index 4f5e5fc6..c5d3fe7a 100644
--- a/verilog/VerilogWriter.cc
+++ b/verilog/VerilogWriter.cc
@@ -447,12 +447,13 @@ VerilogWriter::writeAssigns(const Instance *inst)
     if (term) {
       Net *net = network_->net(term);
       Port *port = network_->port(pin);
-      if (port
+      if (net
+          && port
           && (include_pwr_gnd_
               || !(network_->isPower(net) || network_->isGround(net)))
           && (network_->direction(port)->isAnyOutput()
               || (include_pwr_gnd_ && network_->direction(port)->isPowerGround()))
-          && !stringEqual(network_->name(port), network_->name(net))) {
+          && network_->name(port) != network_->name(net)) {
         // Port name is different from net name.
         std::string port_vname = netVerilogName(std::string(network_->name(port)));
         std::string net_vname = netVerilogName(std::string(network_->name(net)));