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parasitics reduce find max resistance

This commit is contained in:
James Cherry 2021-02-05 14:12:09 -07:00
parent 40737739a6
commit b1b0208799
1 changed files with 22 additions and 9 deletions
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31
parasitics/ReduceParasitics.cc
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@ -27,6 +27,8 @@
namespace sta { namespace sta {
using std::max;
typedef Map<ParasiticNode*, double> ParasiticNodeValueMap; typedef Map<ParasiticNode*, double> ParasiticNodeValueMap;
typedef Map<ParasiticDevice*, double> ParasiticDeviceValueMap; typedef Map<ParasiticDevice*, double> ParasiticDeviceValueMap;
typedef Set<ParasiticNode*> ParasiticNodeSet; typedef Set<ParasiticNode*> ParasiticNodeSet;
@ -55,10 +57,12 @@ protected:
ParasiticNode *node, ParasiticNode *node,
ParasiticDevice *from_res, ParasiticDevice *from_res,
const ParasiticAnalysisPt *ap, const ParasiticAnalysisPt *ap,
double src_resistance,
double &y1, double &y1,
double &y2, double &y2,
double &y3, double &y3,
double &dwn_cap); double &dwn_cap,
double &max_resistance);
void visit(ParasiticNode *node); void visit(ParasiticNode *node);
bool isVisited(ParasiticNode *node); bool isVisited(ParasiticNode *node);
void leave(ParasiticNode *node); void leave(ParasiticNode *node);
@ -118,7 +122,9 @@ ReduceToPi::reduceToPi(const Pin *drvr_pin,
cnst_min_max_ = cnst_min_max; cnst_min_max_ = cnst_min_max;
double y1, y2, y3, dcap; double y1, y2, y3, dcap;
reducePiDfs(drvr_pin, drvr_node, 0, ap, y1, y2, y3, dcap); double max_resistance = 0.0;
reducePiDfs(drvr_pin, drvr_node, nullptr, ap, 0.0,
y1, y2, y3, dcap, max_resistance);
if (y2 == 0.0 && y3 == 0.0) { if (y2 == 0.0 && y3 == 0.0) {
// Capacitive load. // Capacitive load.
@ -131,9 +137,12 @@ ReduceToPi::reduceToPi(const Pin *drvr_pin,
c2 = y1 - y2 * y2 / y3; c2 = y1 - y2 * y2 / y3;
rpi = -y3 * y3 / (y2 * y2 * y2); rpi = -y3 * y3 / (y2 * y2 * y2);
} }
if (stringEq(network_->pathName(drvr_pin),"ld"))
printf(" Pi model c2=%.3g rpi=%.3g c1=%.3g max_r=%.3g\n",
c2, rpi, c1, max_resistance);
debugPrint(debug_, "parasitic_reduce", 2, debugPrint(debug_, "parasitic_reduce", 2,
" Pi model c2=%.3g rpi=%.3g c1=%.3g", " Pi model c2=%.3g rpi=%.3g c1=%.3g max_r=%.3g",
c2, rpi, c1); c2, rpi, c1, max_resistance);
} }
// Find admittance moments. // Find admittance moments.
@ -141,11 +150,13 @@ void
ReduceToPi::reducePiDfs(const Pin *drvr_pin, ReduceToPi::reducePiDfs(const Pin *drvr_pin,
ParasiticNode *node, ParasiticNode *node,
ParasiticDevice *from_res, ParasiticDevice *from_res,
const ParasiticAnalysisPt *ap, const ParasiticAnalysisPt *ap,
double src_resistance,
double &y1, double &y1,
double &y2, double &y2,
double &y3, double &y3,
double &dwn_cap) double &dwn_cap,
double &max_resistance)
{ {
double coupling_cap = 0.0; double coupling_cap = 0.0;
ParasiticDeviceIterator *device_iter1 = parasitics_->deviceIterator(node); ParasiticDeviceIterator *device_iter1 = parasitics_->deviceIterator(node);
@ -160,6 +171,7 @@ ReduceToPi::reducePiDfs(const Pin *drvr_pin,
+ coupling_cap * coupling_cap_multiplier_ + coupling_cap * coupling_cap_multiplier_
+ pinCapacitance(node); + pinCapacitance(node);
y2 = y3 = 0.0; y2 = y3 = 0.0;
max_resistance = max(max_resistance, src_resistance);
visit(node); visit(node);
ParasiticDeviceIterator *device_iter2 = parasitics_->deviceIterator(node); ParasiticDeviceIterator *device_iter2 = parasitics_->deviceIterator(node);
@ -178,16 +190,17 @@ ReduceToPi::reducePiDfs(const Pin *drvr_pin,
markLoopResistor(device); markLoopResistor(device);
} }
else { else {
double r = parasitics_->value(device, ap);
double yd1, yd2, yd3, dcap; double yd1, yd2, yd3, dcap;
reducePiDfs(drvr_pin, onode, device, ap, yd1, yd2, yd3,dcap); reducePiDfs(drvr_pin, onode, device, ap, src_resistance + r,
yd1, yd2, yd3, dcap, max_resistance);
// Rule 3. Upstream traversal of a series resistor. // Rule 3. Upstream traversal of a series resistor.
// Rule 4. Parallel admittances add. // Rule 4. Parallel admittances add.
double r = parasitics_->value(device, ap);
y1 += yd1; y1 += yd1;
y2 += yd2 - r * yd1 * yd1; y2 += yd2 - r * yd1 * yd1;
y3 += yd3 - 2 * r * yd1 * yd2 + r * r * yd1 * yd1 * yd1; y3 += yd3 - 2 * r * yd1 * yd2 + r * r * yd1 * yd1 * yd1;
dwn_cap += dcap; dwn_cap += dcap;
} }
} }
} }
} }