From 0544d02ca25e8ea9ed928931bb486638e6a1ecf8 Mon Sep 17 00:00:00 2001
From: Matt Guthaus <mrg@ucsc.edu>
Date: Thu, 25 Oct 2018 13:36:35 -0700
Subject: [PATCH] Refactor router to have pin_groups for pins and router_tech
 file

---
 compiler/router/pin_group.py     | 238 +++++++++++++++++++++
 compiler/router/router.py        | 354 +++----------------------------
 compiler/router/router_tech.py   |  78 +++++++
 compiler/router/supply_router.py |  65 +++---
 4 files changed, 378 insertions(+), 357 deletions(-)
 create mode 100644 compiler/router/pin_group.py
 create mode 100644 compiler/router/router_tech.py

diff --git a/compiler/router/pin_group.py b/compiler/router/pin_group.py
new file mode 100644
index 00000000..b1599a8e
--- /dev/null
+++ b/compiler/router/pin_group.py
@@ -0,0 +1,238 @@
+from vector3d import vector3d
+from tech import drc
+import debug
+
+class pin_group:
+    """
+    A class to represent a group of touching rectangular design pin. 
+    It requires a router to define the track widths and blockages which 
+    determine how pin shapes get mapped to tracks. 
+    """
+    def __init__(self, name, pin_shapes, router):
+        self.name = name
+        # Flag for when it is routed
+        self.routed = False
+        self.shapes = pin_shapes
+        self.router = router
+        # These are the corresponding pin grids for each pin group.
+        self.grids = set()
+        # The corresponding set of partially blocked grids for each pin group.
+        # These are blockages for other nets but unblocked for routing this group.
+        self.blockages = set()
+
+    def set_routed(self, value=True):
+        self.routed = value
+
+    def is_routed(self):
+        return self.routed
+        
+    def remove_redundant_shapes(self, pin_list):
+        """
+        Remove any pin layout that is contained within another.
+        """
+        local_debug = False
+        if local_debug:
+            debug.info(0,"INITIAL:",pin_list)
+        
+        # Make a copy of the list to start
+        new_pin_list = pin_list.copy()
+        
+        # This is n^2, but the number is small
+        for pin1 in pin_list:
+            for pin2 in pin_list:
+                # Can't contain yourself
+                if pin1 == pin2:
+                    continue
+                if pin2.contains(pin1):
+                    # It may have already been removed by being enclosed in another pin
+                    if pin1 in new_pin_list:
+                        new_pin_list.remove(pin1)
+                        
+        if local_debug:
+            debug.info(0,"FINAL  :",new_pin_list)
+        return new_pin_list
+
+    # FIXME: This relies on some technology parameters from router which is not clearn.
+    def compute_enclosures(self):
+        """
+        Find the minimum rectangle enclosures of the given tracks.
+        """
+        # Enumerate every possible enclosure
+        pin_list = []
+        for seed in self.grids:
+            (ll, ur) = self.enclose_pin_grids(seed)
+            enclosure = self.router.compute_pin_enclosure(ll, ur, ll.z)
+            pin_list.append(enclosure)
+
+        #return pin_list
+        # We used to do this, but smaller enclosures can be
+        return self.remove_redundant_shapes(pin_list)
+        
+    def compute_enclosure(self, pin, enclosure):
+        """ 
+        Compute an enclosure to connect the pin to the enclosure shape. 
+        This assumes the shape will be the dimension of the pin.
+        """
+        if pin.xoverlaps(enclosure):
+            # Is it vertical overlap, extend pin shape to enclosure
+            plc = pin.lc()
+            prc = pin.rc()
+            elc = enclosure.lc()
+            erc = enclosure.rc()
+            ymin = min(plc.y,elc.y)
+            ymax = max(plc.y,elc.y)
+            ll = vector(plc.x, ymin)
+            ur = vector(prc.x, ymax)
+            p = pin_layout(pin.name, [ll, ur], pin.layer) 
+        elif pin.yoverlaps(enclosure):
+            # Is it horizontal overlap, extend pin shape to enclosure
+            pbc = pin.bc()
+            puc = pin.uc()
+            ebc = enclosure.bc()
+            euc = enclosure.uc()
+            xmin = min(pbc.x,ebc.x)
+            xmax = max(pbc.x,ebc.x)
+            ll = vector(xmin, pbc.y)
+            ur = vector(xmax, puc.y)
+            p = pin_layout(pin.name, [ll, ur], pin.layer)
+        else:
+            # Neither, so we must do a corner-to corner
+            pc = pin.center()
+            ec = enclosure.center()
+            xmin = min(pc.x, ec.x)
+            xmax = max(pc.x, ec.x)
+            ymin = min(pc.y, ec.y)
+            ymax = max(pc.y, ec.y)
+            ll = vector(xmin, ymin)
+            ur = vector(xmax, ymax)
+            p = pin_layout(pin.name, [ll, ur], pin.layer)
+
+        return p
+
+    def find_smallest_connector(self, enclosure_list):
+        """
+        Compute all of the connectors between non-overlapping pins and enclosures.
+        Return the smallest.
+        """
+        smallest = None
+        for pin in self.shapes:
+            for enclosure in enclosure_list:
+                new_enclosure = self.compute_enclosure(pin, enclosure)
+                if smallest == None or new_enclosure.area()<smallest.area():
+                    smallest = new_enclosure
+                    
+        return smallest
+
+    def find_smallest_overlapping(self, shape_list):
+        """
+        Find the smallest area shape in shape_list that overlaps with any 
+        pin in pin_list by a min width.
+        """
+
+        smallest_shape = None
+        for pin in self.shapes:
+            # They may not be all on the same layer... in the future.
+            zindex=self.router.get_zindex(pin.layer_num)
+            (min_width,min_space) = self.router.get_layer_width_space(zindex)
+
+            # Now compare it with every other shape to check how much they overlap
+            for other in shape_list:
+                overlap_length = pin.overlap_length(other)
+                if overlap_length > min_width:
+                    if smallest_shape == None or other.area()<smallest_shape.area():
+                        smallest_shape = other
+                        
+        return smallest_shape
+    
+    def overlap_any_shape(self, pin_list, shape_list):
+        """
+        Does the given pin overlap any of the shapes in the pin list.
+        """
+        for pin in pin_list:
+            for other in shape_list:
+                if pin.overlaps(other):
+                    return True
+
+        return False
+
+    
+    def max_pin_layout(self, pin_list):
+        """ 
+        Return the max area pin_layout
+        """
+        biggest = pin_list[0]
+        for pin in pin_list:
+            if pin.area() > biggest.area():
+                biggest = pin
+                
+        return pin
+
+    def enclose_pin_grids(self, seed):
+        """
+        This encloses a single pin component with a rectangle
+        starting with the seed and expanding right until blocked
+        and then up until blocked.
+        """
+
+        # We may have started with an empty set
+        if not self.grids:
+            return None
+
+        # Start with the seed
+        ll = seed
+
+        # Start with the ll and make the widest row
+        row = [ll]
+        # Move right while we can
+        while True:
+            right = row[-1] + vector3d(1,0,0)
+            # Can't move if not in the pin shape 
+            if right in self.grids and right not in self.router.blocked_grids:
+                row.append(right)
+            else:
+                break
+        # Move up while we can
+        while True:
+            next_row = [x+vector3d(0,1,0) for x in row]
+            for cell in next_row:
+                # Can't move if any cell is not in the pin shape 
+                if cell not in self.grids or cell in self.router.blocked_grids:
+                    break
+            else:
+                row = next_row
+                # Skips the second break
+                continue
+            # Breaks from the nested break
+            break
+
+        # Add a shape from ll to ur
+        ur = row[-1]
+        return (ll,ur)
+
+    
+    def enclose_pin(self):
+        """
+        This will find the biggest rectangle enclosing some grid squares and
+        put a rectangle over it. It does not enclose grid squares that are blocked
+        by other shapes.
+        """
+        # Compute the enclosure pin_layout list of the set of tracks
+        enclosure_list = self.compute_enclosures()
+        self.enclosure = self.find_smallest_overlapping(enclosure_list)
+        if not self.enclosure:
+            self.enclosure = self.find_smallest_connector(enclosure_list)
+        debug.info(2,"Computed enclosure {0} {1}".format(self.name, self.enclosure))  
+            
+    def add_enclosure(self, cell):
+        """
+        Add the enclosure shape to the given cell.
+        """
+        debug.info(2,"Adding enclosure {0} {1}".format(self.name, self.enclosure))  
+        self.router.cell.add_rect(layer=self.enclosure.layer,
+                                  offset=self.enclosure.ll(),
+                                  width=self.enclosure.width(),
+                                  height=self.enclosure.height())
+            
+
+    
+    
diff --git a/compiler/router/router.py b/compiler/router/router.py
index a3878b5e..7269e07f 100644
--- a/compiler/router/router.py
+++ b/compiler/router/router.py
@@ -1,17 +1,18 @@
 import sys
 import gdsMill
-from tech import drc,GDS,layer
-from contact import contact
+from tech import drc,GDS
 import math
 import debug
+from router_tech import router_tech
 from pin_layout import pin_layout
+from pin_group import pin_group
 from vector import vector
 from vector3d import vector3d 
 from globals import OPTS
 from pprint import pformat
 import grid_utils
 
-class router:
+class router(router_tech):
     """
     A router class to read an obstruction map from a gds and plan a
     route on a given layer. This is limited to two layer routes.
@@ -23,6 +24,8 @@ class router:
         This will instantiate a copy of the gds file or the module at (0,0) and
         route on top of this. The blockages from the gds/module will be considered.
         """
+        router_tech.__init__(self, layers)
+        
         self.cell = design
 
         # If didn't specify a gds blockage file, write it out to read the gds
@@ -37,22 +40,16 @@ class router:
         self.reader.loadFromFile(gds_filename)
         self.top_name = self.layout.rootStructureName
 
-        # Set up layers and track sizes
-        self.set_layers(layers)
-        
         ### The pin data structures
-        # A map of pin names to pin structures
+        # A map of pin names to a set of pin_layout structures
         self.pins = {}
-        # This is a set of all pins so that we don't create blockages for these shapes.
+        # This is a set of all pins (ignoring names) so that can quickly not create blockages for pins
+        # (They will be blocked based on the names we are routing)
         self.all_pins = set()
         
-        # This is a set of pin groups. Each group consists of overlapping pin shapes on the same layer.
+        # A map of pin names to a list of pin groups
+        # A pin group is a set overlapping pin shapes on the same layer.
         self.pin_groups = {}
-        # These are the corresponding pin grids for each pin group.
-        self.pin_grids = {}
-        # The corresponding set of partially blocked grids for each pin group.
-        # These are blockages for other nets but unblocked for this component.
-        self.pin_blockages = {}        
         
         ### The blockage data structures
         # A list of metal shapes (using the same pin_layout structure) that are not pins but blockages.
@@ -78,8 +75,6 @@ class router:
         self.pins = {}
         self.all_pins = set()
         self.pin_groups = {}        
-        self.pin_grids = {}
-        self.pin_blockages = {}        
         # DO NOT clear the blockages as these don't change
         self.rg.reinit()
 
@@ -88,19 +83,6 @@ class router:
         """ If we want to route something besides the top-level cell."""
         self.top_name = top_name
 
-    def get_zindex(self,layer_num):
-        if layer_num==self.horiz_layer_number:
-            return 0
-        else:
-            return 1
-
-    def get_layer(self, zindex):
-        if zindex==1:
-            return self.vert_layer_name
-        elif zindex==0:
-            return self.horiz_layer_name
-        else:
-            debug.error("Invalid zindex {}".format(zindex),-1)
         
     def is_wave(self,path):
         """
@@ -108,40 +90,6 @@ class router:
         """
         return len(path[0])>1
     
-    def set_layers(self, layers):
-        """
-        Allows us to change the layers that we are routing on. First layer
-        is always horizontal, middle is via, and last is always
-        vertical.
-        """
-        self.layers = layers
-        (self.horiz_layer_name, self.via_layer_name, self.vert_layer_name) = self.layers
-
-        # This is the minimum routed track spacing
-        via_connect = contact(self.layers, (1, 1))
-        self.max_via_size = max(via_connect.width,via_connect.height)
-        
-        self.vert_layer_minwidth = drc("minwidth_{0}".format(self.vert_layer_name))
-        self.vert_layer_spacing = drc(str(self.vert_layer_name)+"_to_"+str(self.vert_layer_name))
-        self.vert_layer_number = layer[self.vert_layer_name]
-        
-        self.horiz_layer_minwidth = drc("minwidth_{0}".format(self.horiz_layer_name))
-        self.horiz_layer_spacing = drc(str(self.horiz_layer_name)+"_to_"+str(self.horiz_layer_name))
-        self.horiz_layer_number = layer[self.horiz_layer_name]
-
-        self.horiz_track_width = self.max_via_size + self.horiz_layer_spacing
-        self.vert_track_width = self.max_via_size + self.vert_layer_spacing
-
-        # We'll keep horizontal and vertical tracks the same for simplicity.
-        self.track_width = max(self.horiz_track_width,self.vert_track_width)
-        debug.info(1,"Track width: "+str(self.track_width))
-
-        self.track_widths = [self.track_width] * 2
-        self.track_factor = [1/self.track_width] * 2
-        debug.info(1,"Track factor: {0}".format(self.track_factor))
-
-        # When we actually create the routes, make them the width of the track (minus 1/2 spacing on each side)
-        self.layer_widths = [self.track_width - self.horiz_layer_spacing, 1, self.track_width - self.vert_layer_spacing]
 
     def retrieve_pins(self,pin_name):
         """
@@ -224,14 +172,16 @@ class router:
         self.set_supply_rail_blocked(True)
         
         # Block all of the pin components (some will be unblocked if they're a source/target)
-        for name in self.pin_grids.keys():
-            self.set_blockages(self.pin_grids[name],True)
+        for name in self.pin_groups.keys():
+            blockage_grids = {y for x in self.pin_groups[name] for y in x.grids}
+            self.set_blockages(blockage_grids,True)
 
 
         # Don't mark the other components as targets since we want to route
         # directly to a rail, but unblock all the source components so we can
         # route over them
-        self.set_blockages(self.pin_grids[pin_name],False)
+        blockage_grids = {y for x in self.pin_groups[pin_name] for y in x.grids}
+        self.set_blockages(blockage_grids,False)
             
         # These are the paths that have already been routed.
         self.set_path_blockages()
@@ -458,23 +408,6 @@ class router:
         return set([best_coord])
 
         
-    def get_layer_width_space(self, zindex, width=0, length=0):
-        """
-        Return the width and spacing of a given layer
-        and wire of a given width and length.
-        """
-        if zindex==1:
-            layer_name = self.vert_layer_name
-        elif zindex==0:
-            layer_name = self.horiz_layer_name
-        else:
-            debug.error("Invalid zindex for track", -1)
-
-        min_width = drc("minwidth_{0}".format(layer_name), width, length)
-        min_spacing = drc(str(layer_name)+"_to_"+str(layer_name), width, length)
-
-        return (min_width,min_spacing)
-
     def convert_pin_coord_to_tracks(self, pin, coord):
         """ 
         Given a pin and a track coordinate, determine if the pin overlaps enough.
@@ -599,24 +532,18 @@ class router:
         reduced_classes = combine_classes(equiv_classes)
         if local_debug:
             debug.info(0,"FINAL  ",reduced_classes)
-        self.pin_groups[pin_name]=reduced_classes
+        self.pin_groups[pin_name] = [pin_group(name=pin_name, pin_shapes=x, router=self) for x in reduced_classes]
         
     def convert_pins(self, pin_name):
         """ 
         Convert the pin groups into pin tracks and blockage tracks.
         """
-        try:
-            self.pin_grids[pin_name]
-        except:
-            self.pin_grids[pin_name] = []
-
-        found_pin = False
         for pg in self.pin_groups[pin_name]:
             #print("PG  ",pg)
             # Keep the same groups for each pin
             pin_set = set()
             blockage_set = set()
-            for pin in pg:
+            for pin in pg.shapes:
                 debug.info(2,"  Converting {0}".format(pin))
                 # Determine which tracks the pin overlaps 
                 pin_in_tracks=self.convert_pin_to_tracks(pin_name, pin)
@@ -644,7 +571,7 @@ class router:
                 debug.error("Unable to find unblocked pin on grid.")
 
             # We need to route each of the components, so don't combine the groups
-            self.pin_grids[pin_name].append(pin_set | blockage_set)
+            pg.grids = pin_set | blockage_set
 
             # Add all of the partial blocked grids to the set for the design
             # if they are not blocked by other metal
@@ -658,143 +585,6 @@ class router:
             #self.blocked_grids.difference_update(pin_set)
 
 
-    def enclose_pin_grids(self, grids, seed):
-        """
-        This encloses a single pin component with a rectangle
-        starting with the seed and expanding right until blocked
-        and then up until blocked.
-        """
-
-        # We may have started with an empty set
-        if not grids:
-            return None
-
-        # Start with the seed
-        ll = seed
-
-        # Start with the ll and make the widest row
-        row = [ll]
-        # Move right while we can
-        while True:
-            right = row[-1] + vector3d(1,0,0)
-            # Can't move if not in the pin shape 
-            if right in grids and right not in self.blocked_grids:
-                row.append(right)
-            else:
-                break
-        # Move up while we can
-        while True:
-            next_row = [x+vector3d(0,1,0) for x in row]
-            for cell in next_row:
-                # Can't move if any cell is not in the pin shape 
-                if cell not in grids or cell in self.blocked_grids:
-                    break
-            else:
-                row = next_row
-                # Skips the second break
-                continue
-            # Breaks from the nested break
-            break
-
-        # Add a shape from ll to ur
-        ur = row[-1]
-        return self.compute_pin_enclosure(ll, ur, ll.z)
-
-    def remove_redundant_shapes(self, pin_list):
-        """
-        Remove any pin layout that is contained within another.
-        """
-        local_debug = False
-        if local_debug:
-            debug.info(0,"INITIAL:",pin_list)
-        
-        # Make a copy of the list to start
-        new_pin_list = pin_list.copy()
-        
-        # This is n^2, but the number is small
-        for pin1 in pin_list:
-            for pin2 in pin_list:
-                # Can't contain yourself
-                if pin1 == pin2:
-                    continue
-                if pin2.contains(pin1):
-                    # It may have already been removed by being enclosed in another pin
-                    if pin1 in new_pin_list:
-                        new_pin_list.remove(pin1)
-                        
-        if local_debug:
-            debug.info(0,"FINAL  :",new_pin_list)
-        return new_pin_list
-
-    def compute_enclosures(self, tracks):
-        """
-        Find the minimum rectangle enclosures of the given tracks.
-        """
-        # Enumerate every possible enclosure
-        pin_list = []
-        for seed in tracks:
-            pin_list.append(self.enclose_pin_grids(tracks, seed))
-
-        #return pin_list
-        # We used to do this, but smaller enclosures can be
-        return self.remove_redundant_shapes(pin_list)
-
-    def overlap_any_shape(self, pin_list, shape_list):
-        """
-        Does the given pin overlap any of the shapes in the pin list.
-        """
-        for pin in pin_list:
-            for other in shape_list:
-                if pin.overlaps(other):
-                    return True
-
-        return False
-
-    def find_smallest_overlapping(self, pin_list, shape_list):
-        """
-        Find the smallest area shape in shape_list that overlaps with any 
-        pin in pin_list by a min width.
-        """
-
-        smallest_shape = None
-        for pin in pin_list:
-            # They may not be all on the same layer... in the future.
-            zindex=self.get_zindex(pin.layer_num)
-            (min_width,min_space) = self.get_layer_width_space(zindex)
-
-            # Now compare it with every other shape to check how much they overlap
-            for other in shape_list:
-                overlap_length = pin.overlap_length(other)
-                if overlap_length > min_width:
-                    if smallest_shape == None or other.area()<smallest_shape.area():
-                        smallest_shape = other
-                        
-        return smallest_shape
-    
-    def max_pin_layout(self, pin_list):
-        """ 
-        Return the max area pin_layout
-        """
-        biggest = pin_list[0]
-        for pin in pin_list:
-            if pin.area() > biggest.area():
-                biggest = pin
-                
-        return pin
-
-    def find_smallest_connector(self, pin_list, enclosure_list):
-        """
-        Compute all of the connectors between non-overlapping pins and enclosures.
-        Return the smallest.
-        """
-        smallest = None
-        for pin in pin_list:
-            for enclosure in enclosure_list:
-                new_enclosure = self.compute_enclosure(pin, enclosure)
-                if smallest == None or new_enclosure.area()<smallest.area():
-                    smallest = new_enclosure
-                    
-        return smallest
     
     def enclose_pins(self):
         """
@@ -806,86 +596,20 @@ class router:
         self.connector_enclosure = []
         self.enclosures = []
         
-        for pin_name in self.pin_grids.keys():
+        for pin_name in self.pin_groups.keys():
             debug.info(1,"Enclosing pins for {}".format(pin_name))
-            debug.check(len(self.pin_groups[pin_name])==len(self.pin_grids[pin_name]),"Unequal pin_group and pin_grid")
-            for pin_group,pin_grid_set in zip(self.pin_groups[pin_name],self.pin_grids[pin_name]):
-
-                # Compute the enclosure pin_layout list of the set of tracks
-                enclosure_list = self.compute_enclosures(pin_grid_set)
-                smallest_enclosure = self.find_smallest_overlapping(pin_group, enclosure_list)
-                if smallest_enclosure:
-                #for smallest_enclosure in enclosure_list:
-                    debug.info(2,"Adding enclosure {0} {1}".format(pin_name, smallest_enclosure))
-                    self.cell.add_rect(layer=smallest_enclosure.layer,
-                                       offset=smallest_enclosure.ll(),
-                                       width=smallest_enclosure.width(),
-                                       height=smallest_enclosure.height())
-                    self.enclosures.append(smallest_enclosure)
-
-                #if self.overlap_any_shape(pin_group, enclosure_list):
-                    #debug.info(2,"Pin overlaps enclosure {0}".format(pin_name))
-                #    pass
-                else:
-                    new_enclosure = self.find_smallest_connector(pin_group, enclosure_list)
-                    debug.info(2,"Adding connector enclosure {0} {1}".format(pin_name, new_enclosure))  
-                    self.cell.add_rect(layer=new_enclosure.layer,
-                                       offset=new_enclosure.ll(),
-                                       width=new_enclosure.width(),
-                                       height=new_enclosure.height())
-                    self.connector_enclosure.append(new_enclosure)
-                                  
-                    
+            for pg in self.pin_groups[pin_name]:
+                pg.enclose_pin()
+                pg.add_enclosure(self.cell)
 
         #self.write_debug_gds("pin_debug.gds", True)
-
-    def compute_enclosure(self, pin, enclosure):
-        """ 
-        Compute an enclosure to connect the pin to the enclosure shape. 
-        This assumes the shape will be the dimension of the pin.
-        """
-        if pin.xoverlaps(enclosure):
-            # Is it vertical overlap, extend pin shape to enclosure
-            plc = pin.lc()
-            prc = pin.rc()
-            elc = enclosure.lc()
-            erc = enclosure.rc()
-            ymin = min(plc.y,elc.y)
-            ymax = max(plc.y,elc.y)
-            ll = vector(plc.x, ymin)
-            ur = vector(prc.x, ymax)
-            p = pin_layout(pin.name, [ll, ur], pin.layer) 
-        elif pin.yoverlaps(enclosure):
-            # Is it horizontal overlap, extend pin shape to enclosure
-            pbc = pin.bc()
-            puc = pin.uc()
-            ebc = enclosure.bc()
-            euc = enclosure.uc()
-            xmin = min(pbc.x,ebc.x)
-            xmax = max(pbc.x,ebc.x)
-            ll = vector(xmin, pbc.y)
-            ur = vector(xmax, puc.y)
-            p = pin_layout(pin.name, [ll, ur], pin.layer)
-        else:
-            # Neither, so we must do a corner-to corner
-            pc = pin.center()
-            ec = enclosure.center()
-            xmin = min(pc.x, ec.x)
-            xmax = max(pc.x, ec.x)
-            ymin = min(pc.y, ec.y)
-            ymax = max(pc.y, ec.y)
-            ll = vector(xmin, ymin)
-            ur = vector(xmax, ymax)
-            p = pin_layout(pin.name, [ll, ur], pin.layer)
-
-        return p
     
     def add_source(self, pin_name):
         """ 
         This will mark the grids for all pin components as a source.
         Marking as source or target also clears blockage status.
         """
-        for i in range(self.num_pin_grids(pin_name)):
+        for i in range(self.num_pin_components(pin_name)):
             self.add_pin_component_source(pin_name, i)
 
     def add_target(self, pin_name):
@@ -893,14 +617,14 @@ class router:
         This will mark the grids for all pin components as a target.
         Marking as source or target also clears blockage status.
         """
-        for i in range(self.num_pin_grids(pin_name)):
+        for i in range(self.num_pin_components(pin_name)):
             self.add_pin_component_target(pin_name, i)
             
     def num_pin_components(self, pin_name):
         """ 
         This returns how many disconnected pin components there are.
         """
-        return len(self.pin_grids[pin_name])
+        return len(self.pin_groups[pin_name])
     
     def add_pin_component_source(self, pin_name, index):
         """ 
@@ -909,7 +633,7 @@ class router:
         """
         debug.check(index<self.num_pin_components(pin_name),"Pin component index too large.")
         
-        pin_in_tracks = self.pin_grids[pin_name][index]
+        pin_in_tracks = self.pin_groups[pin_name][index].grids
         debug.info(1,"Set source: " + str(pin_name) + " " + str(pin_in_tracks))
         self.rg.add_source(pin_in_tracks)
 
@@ -928,7 +652,7 @@ class router:
         """
         debug.check(index<self.num_pin_grids(pin_name),"Pin component index too large.")
         
-        pin_in_tracks = self.pin_grids[pin_name][index]
+        pin_in_tracks = self.pin_groups[pin_name][index].grids
         debug.info(1,"Set target: " + str(pin_name) + " " + str(pin_in_tracks))
         self.rg.add_target(pin_in_tracks)
             
@@ -938,8 +662,8 @@ class router:
         Block all of the pin components.
         """
         debug.info(2,"Setting blockages {0} {1}".format(pin_name,value))
-        for component in self.pin_grids[pin_name]:
-            self.set_blockages(component, value)
+        for pg in self.pin_groups[pin_name]:
+            self.set_blockages(pg.grids, value)
             
 
     def prepare_path(self,path):
@@ -1011,8 +735,7 @@ class router:
     def compute_pin_enclosure(self, ll, ur, zindex, name=""):
         """
         Enclose the tracks from ll to ur in a single rectangle that meets
-        the track DRC rules.  If name is supplied, it is added as a pin and
-        not just a rectangle.
+        the track DRC rules. 
         """
         # Get the layer information
         (width, space) = self.get_layer_width_space(zindex)
@@ -1034,8 +757,6 @@ class router:
     def compute_wide_enclosure(self, ll, ur, zindex, name=""):
         """ 
         Enclose the tracks from ll to ur in a single rectangle that meets the track DRC rules.
-        If name is supplied, it is added as a pin and not just a rectangle.
-
         """
 
         # Find the pin enclosure of the whole track shape (ignoring DRCs)
@@ -1064,19 +785,6 @@ class router:
         return pin
     
 
-    def get_inertia(self,p0,p1):
-        """ 
-        Sets the direction based on the previous direction we came from. 
-        """
-        # direction (index) of movement
-        if p0.x!=p1.x:
-            return 0
-        elif p0.y!=p1.y:
-            return 1
-        else:
-            # z direction
-            return 2
-
     def contract_path(self,path):
         """ 
         Remove intermediate points in a rectilinear path or a wave.
diff --git a/compiler/router/router_tech.py b/compiler/router/router_tech.py
new file mode 100644
index 00000000..20443ecb
--- /dev/null
+++ b/compiler/router/router_tech.py
@@ -0,0 +1,78 @@
+from tech import drc,layer
+from contact import contact
+from pin_group import pin_group
+import debug
+
+class router_tech:
+    """
+    This is a class to hold the router tech constants.
+    """
+    def __init__(self, layers):
+        """
+        Allows us to change the layers that we are routing on. First layer
+        is always horizontal, middle is via, and last is always
+        vertical.
+        """
+        self.layers = layers
+        (self.horiz_layer_name, self.via_layer_name, self.vert_layer_name) = self.layers
+
+        # This is the minimum routed track spacing
+        via_connect = contact(self.layers, (1, 1))
+        self.max_via_size = max(via_connect.width,via_connect.height)
+        
+        self.vert_layer_minwidth = drc("minwidth_{0}".format(self.vert_layer_name))
+        self.vert_layer_spacing = drc(str(self.vert_layer_name)+"_to_"+str(self.vert_layer_name))
+        self.vert_layer_number = layer[self.vert_layer_name]
+        
+        self.horiz_layer_minwidth = drc("minwidth_{0}".format(self.horiz_layer_name))
+        self.horiz_layer_spacing = drc(str(self.horiz_layer_name)+"_to_"+str(self.horiz_layer_name))
+        self.horiz_layer_number = layer[self.horiz_layer_name]
+
+        self.horiz_track_width = self.max_via_size + self.horiz_layer_spacing
+        self.vert_track_width = self.max_via_size + self.vert_layer_spacing
+
+        # We'll keep horizontal and vertical tracks the same for simplicity.
+        self.track_width = max(self.horiz_track_width,self.vert_track_width)
+        debug.info(1,"Track width: "+str(self.track_width))
+
+        self.track_widths = [self.track_width] * 2
+        self.track_factor = [1/self.track_width] * 2
+        debug.info(1,"Track factor: {0}".format(self.track_factor))
+
+        # When we actually create the routes, make them the width of the track (minus 1/2 spacing on each side)
+        self.layer_widths = [self.track_width - self.horiz_layer_spacing, 1, self.track_width - self.vert_layer_spacing]
+        
+        
+    
+    def get_zindex(self,layer_num):
+        if layer_num==self.horiz_layer_number:
+            return 0
+        else:
+            return 1
+
+    def get_layer(self, zindex):
+        if zindex==1:
+            return self.vert_layer_name
+        elif zindex==0:
+            return self.horiz_layer_name
+        else:
+            debug.error("Invalid zindex {}".format(zindex),-1)
+
+    def get_layer_width_space(self, zindex, width=0, length=0):
+        """
+        Return the width and spacing of a given layer
+        and wire of a given width and length.
+        """
+        if zindex==1:
+            layer_name = self.vert_layer_name
+        elif zindex==0:
+            layer_name = self.horiz_layer_name
+        else:
+            debug.error("Invalid zindex for track", -1)
+
+        min_width = drc("minwidth_{0}".format(layer_name), width, length)
+        min_spacing = drc(str(layer_name)+"_to_"+str(layer_name), width, length)
+
+        return (min_width,min_spacing)
+
+            
diff --git a/compiler/router/supply_router.py b/compiler/router/supply_router.py
index 597b6b1d..c7424b08 100644
--- a/compiler/router/supply_router.py
+++ b/compiler/router/supply_router.py
@@ -1,9 +1,10 @@
 import gdsMill
 import tech
-from contact import contact
 import math
 import debug
 from globals import OPTS
+from contact import contact
+from pin_group import pin_group
 from pin_layout import pin_layout
 from vector3d import vector3d 
 from router import router
@@ -83,15 +84,15 @@ class supply_router(router):
         # Determine the rail locations
         self.route_supply_rails(self.vdd_name,1)
         #self.write_debug_gds("debug_rails.gds",stop_program=True)
-        
-        remaining_vdd_pin_indices = self.route_simple_overlaps(vdd_name)
-        remaining_gnd_pin_indices = self.route_simple_overlaps(gnd_name)
+
+        self.route_simple_overlaps(vdd_name)
+        self.route_simple_overlaps(gnd_name)
         #self.write_debug_gds("debug_simple_route.gds",stop_program=True)
         
         # Route the supply pins to the supply rails
         # Route vdd first since we want it to be shorter
-        self.route_pins_to_rails(vdd_name, remaining_vdd_pin_indices)
-        self.route_pins_to_rails(gnd_name, remaining_gnd_pin_indices)
+        self.route_pins_to_rails(vdd_name)
+        self.route_pins_to_rails(gnd_name)
         #self.write_debug_gds("debug_pin_routes.gds",stop_program=True)
         
         #self.write_debug_gds("final.gds")  
@@ -105,21 +106,18 @@ class supply_router(router):
         This checks for simple cases where a pin component already overlaps a supply rail.
         It will add an enclosure to ensure the overlap in wide DRC rule cases.
         """
-        num_components = self.num_pin_components(pin_name)
-        remaining_pins = []
         supply_tracks = self.supply_rail_tracks[pin_name]
-
-        for index in range(num_components):
-            pin_in_tracks = self.pin_grids[pin_name][index]
-            common_set = supply_tracks & pin_in_tracks
-
-            if len(common_set)==0:
-                # if no overlap, add it to the complex route pins
-                remaining_pins.append(index)
-            else:
-                self.create_simple_overlap_enclosure(pin_name, common_set)
+        for pg in self.pin_groups[pin_name]:
+            if pg.is_routed():
+                continue
             
-        return remaining_pins
+            common_set = supply_tracks & pg.grids
+
+            if len(common_set)>0:
+                self.create_simple_overlap_enclosure(pin_name, common_set)
+                pg.set_routed()
+            
+
 
     def recurse_simple_overlap_enclosure(self, pin_name, start_set, direct):
         """
@@ -167,7 +165,9 @@ class supply_router(router):
             if not new_set:
                 new_set = self.recurse_simple_overlap_enclosure(pin_name, start_set, direction.WEST)
 
-        enclosure_list = self.compute_enclosures(new_set)
+        pg = pin_group(name=pin_name, pin_shapes=[], router=self)
+        pg.grids=new_set
+        enclosure_list = pg.compute_enclosures()
         for pin in enclosure_list:
             debug.info(2,"Adding simple overlap enclosure {0} {1}".format(pin_name, pin))
             self.cell.add_rect(layer=pin.layer,
@@ -464,23 +464,26 @@ class supply_router(router):
         self.supply_rail_wire_tracks[pin_name] = wire_set
 
         
-    def route_pins_to_rails(self, pin_name, remaining_component_indices):
+    def route_pins_to_rails(self, pin_name):
         """
         This will route each of the remaining pin components to the supply rails. 
         After it is done, the cells are added to the pin blockage list.
         """
 
-        
+        remaining_components = sum(not x.is_routed() for x in self.pin_groups[pin_name])
         debug.info(1,"Pin {0} has {1} remaining components to route.".format(pin_name,
-                                                                             len(remaining_component_indices)))
+                                                                             remaining_components))
 
-        recent_paths = []
-        # For every component
-        for index in remaining_component_indices:
+        for index,pg in enumerate(self.pin_groups[pin_name]):
+            if pg.is_routed():
+                continue
             debug.info(2,"Routing component {0} {1}".format(pin_name, index))
-            
+
+            # Clear everything in the routing grid.
             self.rg.reinit()
-            
+
+            # This is inefficient since it is non-incremental, but it was
+            # easier to debug.
             self.prepare_blockages(pin_name)
             
             # Add the single component of the pin as the source
@@ -491,16 +494,10 @@ class supply_router(router):
             # Don't add the other pins, but we could?
             self.add_supply_rail_target(pin_name)
 
-            # Add the previous paths as targets too
-            #self.add_path_target(recent_paths)
-
-            #print(self.rg.target)
-            
             # Actually run the A* router
             if not self.run_router(detour_scale=5):
                 self.write_debug_gds()
             
-            recent_paths.append(self.paths[-1])
 
     
     def add_supply_rail_target(self, pin_name):