Enhanced LVS with 'join_symmetric_nets'. Updated doc. Added test.

src/lay/lay/doc/about/drc_ref.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>

src/lay/lay/doc/about/drc_ref_global.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>
@@ -151,7 +151,7 @@ l1and2, l1minus2 = cheat("UNIT_CELL) do
 end
 </pre>
 </p><p>
-(Technically, the check code block is a Ruby Proc and cannot create variables
+(Technically, the cheat code block is a Ruby Proc and cannot create variables
 outside it's scope. Hence the results of this code block have to be passed
 through the "cheat" method).
 </p><p>
@@ -234,7 +234,6 @@ See <a href="/about/drc_ref_netter.xml#connect_global">Netter#connect_global</a>
 <a name="connect_implicit"/><p>Usage:</p>
 <ul>
 <li><tt>connect_implicit(label_pattern)</tt></li>
-<li><tt>connect_implicit(cell_pattern, label_pattern)</tt></li>
 </ul>
 <p>
 See <a href="/about/drc_ref_netter.xml#connect_implicit">Netter#connect_implicit</a> for a description of that function.
@@ -769,7 +768,7 @@ a new target will be set up.
 </p><p>
 <ul>
 <li>A string "@n" (n is an integer) specifying output to a layout in the current panel </li>
-<li>A string "@+" specifying output to a new layout in the current panel</li>
+<li>A string "@+" specifying output to a new layout in the current panel </li>
 <li>A layout filename </li>
 <li>A <class_doc href="Layout">Layout</class_doc> object </li>
 <li>A <class_doc href="Cell">Cell</class_doc> object </li>

src/lay/lay/doc/about/drc_ref_layer.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>
@@ -751,6 +751,19 @@ The following image shows the effect of the "interacting" method (input1: red, i
 </tr>
 </table>
 </p>
+<h2>"intersections" - Returns the intersection points of intersecting edge segments for two edge collections</h2>
+<keyword name="intersections"/>
+<a name="intersections"/><p>Usage:</p>
+<ul>
+<li><tt>layer.intersections(edges)</tt></li>
+</ul>
+<p>
+This operation is similar to the "&amp;" operator, but it does also report intersection points
+between non-colinear, but intersection edges. Such points are reported as point-like,
+degenerated edge objects.
+</p><p>
+This method is available for edge layers. The argument must be an edge layer.
+</p>
 <h2>"is_box?" - Returns true, if the region contains a single box</h2>
 <keyword name="is_box?"/>
 <a name="is_box?"/><p>Usage:</p>

src/lay/lay/doc/about/drc_ref_netter.xml

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 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>
@@ -187,17 +187,17 @@ to shapes belonging to tie-down diodes.
 <li><tt>connect_implicit(cell_pattern, label_pattern)</tt></li>
 </ul>
 <p>
-Use the first version of this method to supply label strings which create implicit net connections
-on the top level circuit. This feature is useful to connect identically labelled nets
+Use this method to supply label strings which create implicit net connections
+on the top level circuit in the first version. This feature is useful to connect identically labelled nets
 while a component isn't integrated yet. If the component is integrated, nets may be connected
 on a higher hierarchy level - e.g. by a power mesh. Inside the component this net consists
 of individual islands. To properly perform netlist extraction and comparison, these islands
 need to be connected even though there isn't a physical connection. "connect_implicit" can
-achieve this if these islands are labelled with the same text on the top level of the
+achive this if these islands are labelled with the same text on the top level of the
 component.
 </p><p>
-In the second version, the pattern can be specified for a cell range (given by a cell glob-style
-name pattern or a single cell name). These pattern are applied to non-top cells. An unspecific pattern
+In the second version, the pattern can be specified for a cell range (given by a cell name pattern or a 
+single cell name). These pattern are applied to non-top cells. The unspecific pattern
 has priority over the cell-specific ones. As the cell selector is a pattern itself, a
 single cell may fall into more than one category. In this case, the label filters are
 combined.

src/lay/lay/doc/about/drc_ref_source.xml

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 <doc>

src/lay/lay/doc/about/lvs_ref.xml

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 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>

src/lay/lay/doc/about/lvs_ref_global.xml

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 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>
@@ -46,6 +46,15 @@ See <a href="/about/lvs_ref_netter.xml#compare">Netter#compare</a> for a descrip
 <p>
 See <a href="/about/lvs_ref_netter.xml#equivalent_pins">Netter#equivalent_pins</a> for a description of that function.
 </p>
+<h2>"join_symmetric_nets" - Joins symmetric nets of selected circuits on the extracted netlist</h2>
+<keyword name="join_symmetric_nets"/>
+<a name="join_symmetric_nets"/><p>Usage:</p>
+<ul>
+<li><tt>join_symmetric_nets(circuit_filter)</tt></li>
+</ul>
+<p>
+See <a href="/about/lvs_ref_netter.xml#join_symmetric_nets">Netter#join_symmetric_nets</a> for a description of that function.
+</p>
 <h2>"max_branch_complexity" - Configures the maximum branch complexity for ambiguous net matching</h2>
 <keyword name="max_branch_complexity"/>
 <a name="max_branch_complexity"/><p>Usage:</p>

src/lay/lay/doc/about/lvs_ref_netter.xml

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 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE language SYSTEM "klayout_doc.dtd">
 
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 <doc>
@@ -110,6 +110,29 @@ If the netlist provides named pins, names can be used instead of numbers.
 Before this method can be used, a schematic netlist needs to be loaded with
 <a href="#schematic">schematic</a>.
 </p>
+<h2>"join_symmetric_nets" - Joins symmetric nets of selected circuits on the extracted netlist</h2>
+<keyword name="join_symmetric_nets"/>
+<a name="join_symmetric_nets"/><p>Usage:</p>
+<ul>
+<li><tt>join_symmetric_nets(circuit_filter)</tt></li>
+</ul>
+<p>
+Nets are symmetrical if swapping them would not modify the circuit.
+Hence they will carry the same potential and can be connected (joined).
+This will simplify the circuit and can be applied before device combination
+(e.g. through "netlist.simplify") to render a schematic-equivalent netlist in some 
+cases where symmetric nodes are split (i.e. "split gate" configuration).
+</p><p>
+This method operates on the extracted netlist (layout). The circuit filter
+specifies the circuits to which to apply this operation. The filter is a
+glob-style pattern. Using "*" for all circuits is possible, but it's 
+discouraged currenty until the reliability of the symmetry detection 
+algorithm is established. Currently it is recommended to apply it only to 
+those circuits for which this feature is required.
+</p><p>
+For the symmetry detection, the specified constraints (e.g. tolerances,
+device filters etc.) apply.
+</p>
 <h2>"lvs_data" - Gets the internal <class_doc href="LayoutVsSchematic">LayoutVsSchematic</class_doc> object</h2>
 <keyword name="lvs_data"/>
 <a name="lvs_data"/><p>Usage:</p>

src/lvs/lvs/built-in-macros/_lvs_engine.rb

@@ -94,6 +94,12 @@ module LVS
     # @synopsis compare
     # See \Netter#compare for a description of that function.
  
+    # %LVS%
+    # @name join_symmetric_nets
+    # @brief Joins symmetric nets of selected circuits on the extracted netlist
+    # @synopsis join_symmetric_nets(circuit_filter)
+    # See \Netter#join_symmetric_nets for a description of that function.
+ 
     # %LVS%
     # @name align
     # @brief Aligns the extracted netlist vs. the schematic by flattening circuits where required
@@ -149,7 +155,7 @@ module LVS
     # @synopsis max_depth(n)
     # See \Netter#max_depth for a description of that function.
 
-    %w(schematic compare align same_nets same_circuits same_device_classes equivalent_pins min_caps max_res max_depth max_branch_complexity).each do |f|
+    %w(schematic compare join_symmetric_nets align same_nets same_circuits same_device_classes equivalent_pins min_caps max_res max_depth max_branch_complexity).each do |f|
       eval <<"CODE"
         def #{f}(*args)
           _netter.#{f}(*args)