OpenRAM/compiler/router/router.py

import sys
import gdsMill
from tech import drc,GDS
from tech import layer as techlayer
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,print_time
from pprint import pformat
import grid_utils
from datetime import datetime

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.
    It populates blockages on a grid class.
    """

    def __init__(self, layers, design, gds_filename=None, rail_track_width=1):
        """
        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, rail_track_width)
        
        self.cell = design

        # If didn't specify a gds blockage file, write it out to read the gds
        # This isn't efficient, but easy for now
        #start_time = datetime.now()
        if not gds_filename:
            gds_filename = OPTS.openram_temp+"temp.gds"
            self.cell.gds_write(gds_filename)

        # Load the gds file and read in all the shapes
        self.layout = gdsMill.VlsiLayout(units=GDS["unit"])
        self.reader = gdsMill.Gds2reader(self.layout)
        self.reader.loadFromFile(gds_filename)
        self.top_name = self.layout.rootStructureName
        #print_time("GDS read",datetime.now(), start_time)
            
        ### The pin data structures
        # A map of pin names to a set of pin_layout structures
        self.pins = {}
        # 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()
        
        # A map of pin names to a list of pin groups
        self.pin_groups = {}
        
        ### The blockage data structures
        # A list of metal shapes (using the same pin_layout structure) that are not pins but blockages.
        self.blockages=[]
        # The corresponding set of blocked grids for above pin shapes
        self.blocked_grids = set()
        
        ### The routed data structures
        # A list of paths that have been "routed"
        self.paths = []
        # A list of path blockages (they might be expanded for wide metal DRC)
        self.path_blockages = []

        # The boundary will determine the limits to the size of the routing grid
        self.boundary = self.layout.measureBoundary(self.top_name)
        # These must be un-indexed to get rid of the matrix type
        self.ll = vector(self.boundary[0][0], self.boundary[0][1])
        # Pad the UR by a few tracks to add an extra rail possibly
        self.ur = vector(self.boundary[1][0], self.boundary[1][1]) + self.track_widths.scale(5,5)

    def clear_pins(self):
        """
        Convert the routed path to blockages.
        Keep the other blockages unchanged.
        """
        self.pins = {}
        self.all_pins = set()
        self.pin_groups = {}        
        # DO NOT clear the blockages as these don't change
        self.rg.reinit()

        
    def set_top(self,top_name):
        """ If we want to route something besides the top-level cell."""
        self.top_name = top_name

        
    def is_wave(self,path):
        """
        Determines if this is a multi-track width wave (True) or a normal route (False)
        """
        return len(path[0])>1
    

    def retrieve_pins(self,pin_name):
        """
        Retrieve the pin shapes on metal 3 from the layout.
        """
        debug.info(2,"Retrieving pins for {}.".format(pin_name))        
        shape_list=self.layout.getAllPinShapes(str(pin_name))
        pin_set = set()
        for shape in shape_list:
            (layer,boundary)=shape
            # GDSMill boundaries are in (left, bottom, right, top) order
            # so repack and snap to the grid
            ll = vector(boundary[0],boundary[1]).snap_to_grid()
            ur = vector(boundary[2],boundary[3]).snap_to_grid()
            rect = [ll,ur]
            pin = pin_layout(pin_name, rect, layer)
            pin_set.add(pin)

        debug.check(len(pin_set)>0,"Did not find any pin shapes for {0}.".format(str(pin_name)))

        self.pins[pin_name] = pin_set
        self.all_pins.update(pin_set)

        for pin in self.pins[pin_name]:
            debug.info(3,"Retrieved pin {}".format(str(pin)))
        

        
    def find_pins(self,pin_name):
        """ 
        Finds the pin shapes and converts to tracks. 
        Pin can either be a label or a location,layer pair: [[x,y],layer].
        """
        debug.info(1,"Finding pins for {}.".format(pin_name))
        #start_time = datetime.now()
        self.retrieve_pins(pin_name)
        #print_time("Retrieved pins",datetime.now(), start_time)        
        #start_time = datetime.now()
        self.analyze_pins(pin_name)
        #print_time("Analyzed pins",datetime.now(), start_time)                

    def find_blockages(self):
        """
        Iterate through all the layers and write the obstacles to the routing grid.
        This doesn't consider whether the obstacles will be pins or not. They get reset later
        if they are not actually a blockage.
        """
        debug.info(1,"Finding blockages.")        
        for layer in [self.vert_layer_number,self.horiz_layer_number]:
            self.retrieve_blockages(layer)
            
            
    def find_pins_and_blockages(self, pin_list):
        """
        Find the pins and blockages in the design 
        """
        # This finds the pin shapes and sorts them into "groups" that are connected
        # This must come before the blockages, so we can not count the pins themselves
        # as blockages.
        for pin in pin_list:
            self.find_pins(pin)

        # This will get all shapes as blockages and convert to grid units
        # This ignores shapes that were pins
        #start_time = datetime.now()
        self.find_blockages()
        #print_time("Find blockags",datetime.now(), start_time)                

        # Convert the blockages to grid units
        #start_time = datetime.now()
        self.convert_blockages()
        #print_time("Find blockags",datetime.now(), start_time)
        
        # This will convert the pins to grid units
        # It must be done after blockages to ensure no DRCs between expanded pins and blocked grids
        #start_time = datetime.now()
        for pin in pin_list:
            self.convert_pins(pin)
        #print_time("Convert pins",datetime.now(), start_time)
        
        #start_time = datetime.now()
        #for pin in pin_list:
        #    self.combine_adjacent_pins(pin)
        #print_time("Combine pins",datetime.now(), start_time)
        #self.write_debug_gds("debug_combine_pins.gds",stop_program=True)

        # Separate any adjacent grids of differing net names that overlap
        # Must be done before enclosing pins
        #start_time = datetime.now()
        self.separate_adjacent_pins(0)
        #print_time("Separate pins",datetime.now(), start_time)
        # For debug
        #self.separate_adjacent_pins(1)
        
        # Enclose the continguous grid units in a metal rectangle to fix some DRCs
        #start_time = datetime.now()
        self.enclose_pins()
        #print_time("Enclose pins",datetime.now(), start_time)
        #self.write_debug_gds("debug_enclose_pins.gds",stop_program=True)

        
    def combine_adjacent_pins(self, pin_name):
        """
        Find pins that have adjacent routing tracks and merge them into a
        single pin_group.  The pins themselves may not be touching, but 
        enclose_pins in the next step will ensure they are touching.
        """        
        debug.info(1,"Combining adjacent pins for {}.".format(pin_name))        
        # Find all adjacencies
        adjacent_pins = {}
        for index1,pg1 in enumerate(self.pin_groups[pin_name]):
            for index2,pg2 in enumerate(self.pin_groups[pin_name]):
                # Cannot combine with yourself, also don't repeat 
                if index1<=index2:
                    continue
                # Combine if at least 1 grid cell is adjacent
                if pg1.adjacent(pg2):
                    if not index1 in adjacent_pins.keys():
                        adjacent_pins[index1] = set([index2])
                    else:
                        adjacent_pins[index1].add(index2)

        # Make a list of indices to ensure every group gets in the new set
        all_indices = set([x for x in range(len(self.pin_groups[pin_name]))])
        
        # Now reconstruct the new groups
        new_pin_groups = []
        for index1,index2_set in adjacent_pins.items():
            # Remove the indices if they are added to the new set
            all_indices.discard(index1)
            all_indices.difference_update(index2_set)

            # Create the combined group starting with the first item
            combined = self.pin_groups[pin_name][index1]
            # Add all of the other items that overlapped
            for index2 in index2_set:
                pg = self.pin_groups[pin_name][index2]
                combined.add_group(pg)
                debug.info(3,"Combining {0} {1}:".format(pin_name, index2))
                debug.info(3, "     {0}\n  {1}".format(combined.pins, pg.pins))
                debug.info(3,"  --> {0}\n      {1}".format(combined.pins,combined.grids))
                new_pin_groups.append(combined)

        # Add the pin groups that weren't added to the new set
        for index in all_indices:
            new_pin_groups.append(self.pin_groups[pin_name][index])

        old_size = len(self.pin_groups[pin_name])   
        # Use the new pin group!
        self.pin_groups[pin_name] = new_pin_groups
        removed_pairs = old_size - len(new_pin_groups)
        debug.info(1, "Combined {0} pin groups for {1}".format(removed_pairs,pin_name))
        
        return removed_pairs
            

    def separate_adjacent_pins(self, separation):
        """
        This will try to separate all grid pins by the supplied number of separation 
        tracks (default is to prevent adjacency).
        """
        debug.info(1,"Separating adjacent pins.")
        # Commented out to debug with SCMOS
        #if separation==0:
        #    return
        
        pin_names = self.pin_groups.keys()
        for pin_name1 in pin_names:
            for pin_name2 in pin_names:
                if pin_name1==pin_name2:
                    continue
                self.separate_adjacent_pin(pin_name1, pin_name2, separation)

    def separate_adjacent_pin(self, pin_name1, pin_name2, separation):
        """
        Go through all of the pin groups and check if any other pin group is 
        within a separation of it.
        If so, reduce the pin group grid to not include the adjacent grid.
        Try to do this intelligently to keep th pins enclosed.
        """
        debug.info(1,"Comparing {0} and {1} adjacency".format(pin_name1, pin_name2))
        for index1,pg1 in enumerate(self.pin_groups[pin_name1]):
            for index2,pg2 in enumerate(self.pin_groups[pin_name2]):
                adj_grids = pg1.adjacent_grids(pg2, separation)
                # These should have the same length, so...
                if len(adj_grids)>0:
                    debug.info(2,"Adjacent grids {0} {1} adj={2}".format(index1,index2,adj_grids))
                    self.remove_adjacent_grid(pg1, pg2, adj_grids)

    def remove_adjacent_grid(self, pg1, pg2, adj_grids):
        """
        Remove one of the adjacent grids in a heuristic manner.
        This will try to keep the groups similar sized by removing from the bigger group.
        """

        if pg1.size()>pg2.size():
            bigger = pg1
            smaller = pg2
        else:
            bigger = pg2
            smaller = pg1
        
        for adj in adj_grids:
            

            # If the adjacent grids are a subset of the secondary grids (i.e. not necessary)
            # remove them from each
            if adj in bigger.secondary_grids:
                debug.info(2,"Removing {} from bigger secondary {}".format(adj, bigger))
                bigger.grids.remove(adj)
                bigger.secondary_grids.remove(adj)
                self.blocked_grids.add(adj)
            elif adj in smaller.secondary_grids:
                debug.info(2,"Removing {} from smaller secondary {}".format(adj, smaller))
                smaller.grids.remove(adj)
                smaller.secondary_grids.remove(adj)
                self.blocked_grids.add(adj)
            else:
                # If we couldn't remove from a secondary grid, we must remove from the primary
                # grid of at least one pin
                if adj in bigger.grids:
                    debug.info(2,"Removing {} from bigger primary {}".format(adj, bigger))
                    bigger.grids.remove(adj)
                elif adj in smaller.grids:
                    debug.info(2,"Removing {} from smaller primary {}".format(adj, smaller))
                    smaller.grids.remove(adj)



    
    def prepare_blockages(self, pin_name):
        """
        Reset and add all of the blockages in the design.
        Names is a list of pins to add as a blockage.
        """
        debug.info(3,"Preparing blockages.")
        
        # Start fresh. Not the best for run-time, but simpler.
        self.clear_blockages()
        # This adds the initial blockges of the design
        #print("BLOCKING:",self.blocked_grids)
        self.set_blockages(self.blocked_grids,True)

        # Block all of the supply rails (some will be unblocked if they're a target)
        self.set_supply_rail_blocked(True)
        
        # Block all of the pin components (some will be unblocked if they're a source/target)
        # Also block the previous routes
        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)
            blockage_grids = {y for x in self.pin_groups[name] for y in x.blockages}
            self.set_blockages(blockage_grids,True)

        # FIXME: These duplicate a bit of work
        # These are the paths that have already been routed.
        self.set_blockages(self.path_blockages)

        # 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
        blockage_grids = {y for x in self.pin_groups[pin_name] for y in x.grids}
        self.set_blockages(blockage_grids,False)
            
        
    # def translate_coordinates(self, coord, mirr, angle, xyShift):
    #     """
    #     Calculate coordinates after flip, rotate, and shift
    #     """
    #     coordinate = []
    #     for item in coord:
    #         x = (item[0]*math.cos(angle)-item[1]*mirr*math.sin(angle)+xyShift[0])
    #         y = (item[0]*math.sin(angle)+item[1]*mirr*math.cos(angle)+xyShift[1])
    #         coordinate += [(x, y)]
    #     return coordinate

    def convert_shape_to_units(self, shape):
        """ 
        Scale a shape (two vector list) to user units 
        """
        unit_factor = [GDS["unit"][0]] * 2
        ll=shape[0].scale(unit_factor)
        ur=shape[1].scale(unit_factor)
        return [ll,ur]

        
    def min_max_coord(self, coord):
        """ 
        Find the lowest and highest corner of a Rectangle 
        """
        coordinate = []
        minx = min(coord[0][0], coord[1][0], coord[2][0], coord[3][0])
        maxx = max(coord[0][0], coord[1][0], coord[2][0], coord[3][0])
        miny = min(coord[0][1], coord[1][1], coord[2][1], coord[3][1])
        maxy = max(coord[0][1], coord[1][1], coord[2][1], coord[3][1])
        coordinate += [vector(minx, miny)]
        coordinate += [vector(maxx, maxy)]
        return coordinate

    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 clear_blockages(self):
        """ 
        Clear all blockages on the grid.
        """
        debug.info(3,"Clearing all blockages")
        self.rg.clear_blockages()
        
    def set_blockages(self, blockages, value=True):
        """ Flag the blockages in the grid """
        self.rg.set_blocked(blockages, value)

    def get_blockage_tracks(self, ll, ur, z):
        debug.info(3,"Converting blockage ll={0} ur={1} z={2}".format(str(ll),str(ur),z))

        block_list = []
        for x in range(int(ll[0]),int(ur[0])+1):
            for y in range(int(ll[1]),int(ur[1])+1):
                block_list.append(vector3d(x,y,z))

        return set(block_list)

    def convert_blockage(self, blockage):
        """ 
        Convert a pin layout blockage shape to routing grid tracks. 
        """
        # Inflate the blockage by half a spacing rule
        [ll,ur]=self.convert_blockage_to_tracks(blockage.inflate())
        zlayer = self.get_zindex(blockage.layer_num)
        blockage_tracks = self.get_blockage_tracks(ll, ur, zlayer)
        return blockage_tracks
        
    def convert_blockages(self):
        """ Convert blockages to grid tracks. """
        debug.info(1,"Converting blockages.")        
        for blockage in self.blockages:
            debug.info(3,"Converting blockage {}".format(str(blockage)))
            blockage_list = self.convert_blockage(blockage)
            self.blocked_grids.update(blockage_list)
        
        
    def retrieve_blockages(self, layer_num): 
        """
        Recursive find boundaries as blockages to the routing grid.
        """

        shapes = self.layout.getAllShapes(layer_num)
        for boundary in shapes:
            ll = vector(boundary[0],boundary[1])
            ur = vector(boundary[2],boundary[3])
            rect = [ll,ur]
            new_pin = pin_layout("blockage{}".format(len(self.blockages)),rect,layer_num)
            
            # If there is a rectangle that is the same in the pins, it isn't a blockage!
            if new_pin not in self.all_pins:
                self.blockages.append(new_pin)


    def convert_point_to_units(self, p):
        """ 
        Convert a path set of tracks to center line path.
        """
        pt = vector3d(p)
        pt = pt.scale(self.track_widths[0],self.track_widths[1],1)
        return pt

    def convert_wave_to_units(self, wave):
        """ 
        Convert a wave to a set of center points 
        """
        return [self.convert_point_to_units(i) for i in wave]
    

    def convert_blockage_to_tracks(self, shape):
        """ 
        Convert a rectangular blockage shape into track units.
        """
        (ll,ur) = shape
        ll = snap_to_grid(ll)
        ur = snap_to_grid(ur)

        # to scale coordinates to tracks
        debug.info(3,"Converting [ {0} , {1} ]".format(ll,ur))
        old_ll = ll
        old_ur = ur
        ll=ll.scale(self.track_factor)
        ur=ur.scale(self.track_factor)
        # We can round since we are using inflated shapes
        # and the track points are at the center
        ll = ll.round()
        ur = ur.round()
        # if ll[0]<45 and ll[0]>35 and ll[1]<5 and ll[1]>-5:
        #     debug.info(0,"Converting [ {0} , {1} ]".format(old_ll,old_ur))
        #     debug.info(0,"Converted [ {0} , {1} ]".format(ll,ur))
        #     pin=self.convert_track_to_shape(ll)            
        #     debug.info(0,"Pin {}".format(pin))
        return [ll,ur]

    def convert_pin_to_tracks(self, pin_name, pin, expansion=0):
        """ 
        Convert a rectangular pin shape into a list of track locations,layers.
        If no pins are "on-grid" (i.e. sufficient overlap) it makes the one with most overlap if it is not blocked.
        If expansion>0, expamine areas beyond the current pin when it is blocked.
        """
        (ll,ur) = pin.rect
        debug.info(3,"Converting pin [ {0} , {1} ]".format(ll,ur))
        
        # scale the size bigger to include neaby tracks
        ll=ll.scale(self.track_factor).floor()
        ur=ur.scale(self.track_factor).ceil()

        # Keep tabs on tracks with sufficient and insufficient overlap
        sufficient_list = set()
        insufficient_list = set()

        zindex=self.get_zindex(pin.layer_num)
        for x in range(int(ll[0])+expansion,int(ur[0])+1+expansion):
            for y in range(int(ll[1]+expansion),int(ur[1])+1+expansion):
                (full_overlap, partial_overlap) = self.convert_pin_coord_to_tracks(pin, vector3d(x,y,zindex))
                if full_overlap:
                    sufficient_list.update([full_overlap])
                if partial_overlap:
                    insufficient_list.update([partial_overlap])
                debug.info(2,"Converting [ {0} , {1} ] full={2}".format(x,y, full_overlap))

        # Return all grids with any potential overlap (sufficient or not)
        return (sufficient_list,insufficient_list)
    

    def get_all_offgrid_pin(self, pin, insufficient_list):
        """ 
        Find a list of all pins with some overlap.
        """
        #print("INSUFFICIENT LIST",insufficient_list)
        # Find the coordinate with the most overlap
        any_overlap = set()
        for coord in insufficient_list:
            full_pin = self.convert_track_to_pin(coord)
            # Compute the overlap with that rectangle
            overlap_rect=pin.compute_overlap(full_pin)
            # Determine the max x or y overlap
            max_overlap = max(overlap_rect)
            if max_overlap>0:
                any_overlap.update([coord])
            
        return any_overlap

    def get_best_offgrid_pin(self, pin, insufficient_list):
        """ 
        Find a list of the single pin with the most overlap.
        """
        #print("INSUFFICIENT LIST",insufficient_list)
        # Find the coordinate with the most overlap
        best_coord = None
        best_overlap = -math.inf
        for coord in insufficient_list:
            full_pin = self.convert_track_to_pin(coord)
            # Compute the overlap with that rectangle
            overlap_rect=pin.compute_overlap(full_pin)
            # Determine the min x or y overlap
            min_overlap = min(overlap_rect)
            if min_overlap>best_overlap:
                best_overlap=min_overlap
                best_coord=coord
            
        return set([best_coord])
    
    def get_furthest_offgrid_pin(self, pin, insufficient_list):
        """ 
        Get a grid cell that is the furthest from the blocked grids.
        """
        
        #print("INSUFFICIENT LIST",insufficient_list)
        # Find the coordinate with the most overlap
        best_coord = None
        best_dist = math.inf
        for coord in insufficient_list:
            min_dist = grid_utils.distance_set(coord, self.blocked_grids)
            if min_dist<best_dist:
                best_dist=min_dist
                best_coord=coord
            
        return set([best_coord])

    def get_nearest_offgrid_pin(self, pin, insufficient_list):
        """ 
        Given a pin and a list of grid cells (probably non-overlapping),
        return the nearest grid cell (center to center).
        """
        #print("INSUFFICIENT LIST",insufficient_list)
        # Find the coordinate with the most overlap
        best_coord = None
        best_dist = math.inf
        for coord in insufficient_list:
            track_pin = self.convert_track_to_pin(coord)
            min_dist = pin.distance(track_pin)
            if min_dist<best_dist:
                best_dist=min_dist
                best_coord=coord
            
        return set([best_coord])
    
        
    def convert_pin_coord_to_tracks(self, pin, coord):
        """ 
        Return all tracks that an inflated pin overlaps
        """

        # This is using the full track shape rather than a single track pin shape
        # because we will later patch a connector if there isn't overlap.
        track_pin = self.convert_track_to_shape_pin(coord)

        # This is the normal pin inflated by a minimum design rule
        inflated_pin = pin_layout(pin.name, pin.inflate(0.5*self.track_space), pin.layer)
        
        overlap_length = pin.overlap_length(track_pin)
        debug.info(2,"Check overlap: {0} {1} . {2} = {3}".format(coord, pin.rect, track_pin, overlap_length))
        inflated_overlap_length = inflated_pin.overlap_length(track_pin)
        debug.info(2,"Check overlap: {0} {1} . {2} = {3}".format(coord, inflated_pin.rect, track_pin, inflated_overlap_length))

        # If it overlaps with the pin, it is sufficient
        if overlap_length==math.inf or overlap_length > 0:
            debug.info(2,"  Overlap: {0} >? {1}".format(overlap_length,0))  
            return (coord,None)
        # If it overlaps with the inflated pin, it is partial
        elif inflated_overlap_length==math.inf or inflated_overlap_length > 0:
            debug.info(2,"  Partial overlap: {0} >? {1}".format(inflated_overlap_length,0))  
            return (None,coord)
        else:
            debug.info(2,"  No overlap: {0} {1}".format(overlap_length,0))
            return (None,None)
        



                                                        

    def convert_track_to_pin(self, track):
        """ 
        Convert a grid point into a rectangle shape that is centered
        track in the track and leaves half a DRC space in each direction.
        """
        # calculate lower left 
        x = track.x*self.track_width - 0.5*self.track_width + 0.5*self.track_space
        y = track.y*self.track_width - 0.5*self.track_width + 0.5*self.track_space
        ll = snap_to_grid(vector(x,y))
            
        # calculate upper right
        x = track.x*self.track_width + 0.5*self.track_width - 0.5*self.track_space
        y = track.y*self.track_width + 0.5*self.track_width - 0.5*self.track_space
        ur = snap_to_grid(vector(x,y))

        p = pin_layout("", [ll, ur], self.get_layer(track[2]))
        return p

    def convert_track_to_shape_pin(self, track):
        """ 
        Convert a grid point into a rectangle shape that occupies the entire centered
        track.
        """
        # to scale coordinates to tracks
        x = track[0]*self.track_width - 0.5*self.track_width
        y = track[1]*self.track_width - 0.5*self.track_width
        # offset lowest corner object to to (-track halo,-track halo)
        ll = snap_to_grid(vector(x,y))
        ur = snap_to_grid(ll + vector(self.track_width,self.track_width))

        p = pin_layout("", [ll, ur], self.get_layer(track[2]))
        return p

    def convert_track_to_shape(self, track):
        """ 
        Convert a grid point into a rectangle shape that occupies the entire centered
        track.
        """
        # to scale coordinates to tracks
        x = track[0]*self.track_width - 0.5*self.track_width
        y = track[1]*self.track_width - 0.5*self.track_width
        # offset lowest corner object to to (-track halo,-track halo)
        ll = snap_to_grid(vector(x,y))
        ur = snap_to_grid(ll + vector(self.track_width,self.track_width))

        return [ll,ur]
    
    def convert_track_to_inflated_pin(self, track):
        """ 
        Convert a grid point into a rectangle shape that is inflated by a half DRC space.
        """
        # calculate lower left 
        x = track.x*self.track_width - 0.5*self.track_width - 0.5*self.track_space
        y = track.y*self.track_width - 0.5*self.track_width - 0.5*self.track_space
        ll = snap_to_grid(vector(x,y))
            
        # calculate upper right
        x = track.x*self.track_width + 0.5*self.track_width + 0.5*self.track_space
        y = track.y*self.track_width + 0.5*self.track_width + 0.5*self.track_space
        ur = snap_to_grid(vector(x,y))

        p = pin_layout("", [ll, ur], self.get_layer(track[2]))
        return p
    
    def analyze_pins(self, pin_name):
        """ 
        Analyze the shapes of a pin and combine them into groups which are connected.
        """
        debug.info(2,"Analyzing pin groups for {}.".format(pin_name))        
        
        pin_set = self.pins[pin_name]

        # Put each pin in an equivalence class of it's own
        equiv_classes = [set([x]) for x in pin_set]
        def combine_classes(equiv_classes):
            for class1 in equiv_classes:
                for class2 in equiv_classes:
                    if class1 == class2:
                        continue
                    # Compare each pin in each class,
                    # and if any overlap, update equiv_classes to include the combined the class
                    for p1 in class1:
                        for p2 in class2:
                            if p1.overlaps(p2):
                                combined_class = class1 | class2
                                equiv_classes.remove(class1)
                                equiv_classes.remove(class2)
                                equiv_classes.append(combined_class)
                                return(equiv_classes)
            return(equiv_classes)

        old_length = math.inf
        while (len(equiv_classes)<old_length):
            old_length = len(equiv_classes)
            equiv_classes = combine_classes(equiv_classes)

        self.pin_groups[pin_name] = [pin_group(name=pin_name, pin_set=x, router=self) for x in equiv_classes]
        
    def convert_pins(self, pin_name):
        """ 
        Convert the pin groups into pin tracks and blockage tracks.
        """
        debug.info(1,"Converting pins for {}.".format(pin_name))        
        for pg in self.pin_groups[pin_name]:
            pg.convert_pin()


    
    def enclose_pins(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.
        """
        for pin_name in self.pin_groups.keys():
            debug.info(1,"Enclosing pins for {}".format(pin_name))
            for pg in self.pin_groups[pin_name]:
                pg.enclose_pin()
                pg.add_enclosure(self.cell)

        #self.write_debug_gds("pin_debug.gds", False)
    
    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_components(pin_name)):
            self.add_pin_component_source(pin_name, i)

    def add_target(self, pin_name):
        """ 
        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_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_groups[pin_name])
    
    def add_pin_component_source(self, pin_name, index):
        """ 
        This will mark only the pin tracks from the indexed pin component as a source.
        It also unsets it as a blockage.
        """
        debug.check(index<self.num_pin_components(pin_name),"Pin component index too large.")
        
        pin_in_tracks = self.pin_groups[pin_name][index].grids
        debug.info(2,"Set source: " + str(pin_name) + " " + str(pin_in_tracks))
        self.rg.add_source(pin_in_tracks)

    def add_path_target(self, paths):
        """ 
        Set all of the paths as a target too.
        """
        for p in paths:
            self.rg.set_target(p)
            self.rg.set_blocked(p,False)

    def add_pin_component_target(self, pin_name, index):
        """ 
        This will mark only the pin tracks from the indexed pin component as a target.
        It also unsets it as a blockage.
        """
        debug.check(index<self.num_pin_grids(pin_name),"Pin component index too large.")
        
        pin_in_tracks = self.pin_groups[pin_name][index].grids
        debug.info(2,"Set target: " + str(pin_name) + " " + str(pin_in_tracks))
        self.rg.add_target(pin_in_tracks)
            

    def set_component_blockages(self, pin_name, value=True):
        """ 
        Block all of the pin components.
        """
        debug.info(3,"Setting blockages {0} {1}".format(pin_name,value))
        for pg in self.pin_groups[pin_name]:
            self.set_blockages(pg.grids, value)
            

    def prepare_path(self,path):
        """ 
        Prepare a path or wave for routing ebedding.
        This tracks the path, simplifies the path and marks it as a path for debug output.
        """
        debug.info(4,"Set path: " + str(path))

        # Keep track of path for future blockages
        #path.set_blocked()
        
        # This is marked for debug
        path.set_path()

        # For debugging... if the path failed to route.
        if False or path==None:
            self.write_debug_gds()

        # First, simplify the path for
        #debug.info(1,str(self.path))        
        contracted_path = self.contract_path(path)
        debug.info(3,"Contracted path: " + str(contracted_path))
        
        return contracted_path
        
        
    def add_route(self,path):
        """ 
        Add the current wire route to the given design instance.
        """
        path=self.prepare_path(path)
        
        debug.info(2,"Adding route: {}".format(str(path)))
        # If it is only a square, add an enclosure to the track
        if len(path)==1:
            self.add_single_enclosure(path[0][0])
        else:
            # convert the path back to absolute units from tracks
            # This assumes 1-track wide again
            abs_path = [self.convert_point_to_units(x[0]) for x in path]
            # Otherwise, add the route which includes enclosures
            self.cell.add_route(layers=self.layers,
                                coordinates=abs_path,
                                layer_widths=self.layer_widths)
            
    def add_single_enclosure(self, track):
        """
        Add a metal enclosure that is the size of the routing grid minus a spacing on each side. 
        """
        pin = self.convert_track_to_pin(track)
        (ll,ur) = pin.rect
        self.cell.add_rect(layer=self.get_layer(track.z),
                           offset=ll,
                           width=ur.x-ll.x,
                           height=ur.y-ll.y)
                                  

        
    def add_via(self,loc,size=1):
        """ 
        Add a via centered at the current location
        """
        loc = self.convert_point_to_units(vector3d(loc[0],loc[1],0))
        self.cell.add_via_center(layers=self.layers,
                                 offset=vector(loc.x,loc.y),
                                 size=(size,size))

    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. 
        """
        layer = self.get_layer(zindex)
        
        # This finds the pin shape enclosed by the track with DRC spacing on the sides
        pin = self.convert_track_to_pin(ll)
        (abs_ll,unused) = pin.rect
        pin = self.convert_track_to_pin(ur)
        (unused,abs_ur) = pin.rect
        #print("enclose ll={0} ur={1}".format(ll,ur))
        #print("enclose ll={0} ur={1}".format(abs_ll,abs_ur))
        
        pin = pin_layout(name, [abs_ll, abs_ur], layer)
        
        return pin
    

    # 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.
    #     """

    #     # Find the pin enclosure of the whole track shape (ignoring DRCs)
    #     (abs_ll,unused) = self.convert_track_to_shape(ll)
    #     (unused,abs_ur) = self.convert_track_to_shape(ur)
        
    #     # Get the layer information
    #     x_distance = abs(abs_ll.x-abs_ur.x)
    #     y_distance = abs(abs_ll.y-abs_ur.y)
    #     shape_width = min(x_distance, y_distance)
    #     shape_length = max(x_distance, y_distance)

    #     # Get the DRC rule for the grid dimensions
    #     (width, space) = self.get_supply_layer_width_space(zindex)
    #     layer = self.get_layer(zindex)

    #     if zindex==0:
    #         spacing = vector(0.5*self.track_width, 0.5*space)
    #     else:
    #         spacing = vector(0.5*space, 0.5*self.track_width)
    #     # Compute the shape offsets with correct spacing
    #     new_ll = abs_ll + spacing
    #     new_ur = abs_ur - spacing
    #     pin = pin_layout(name, [new_ll, new_ur], layer)
        
    #     return pin
    

    def contract_path(self,path):
        """ 
        Remove intermediate points in a rectilinear path or a wave.
        """
        # Waves are always linear, so just return the first and last.
        if self.is_wave(path):
            return [path[0],path[-1]]

        # Make a list only of points that change inertia of the path
        newpath = [path[0]]
        for i in range(1,len(path)-1):
            prev_inertia=self.get_inertia(path[i-1][0],path[i][0])
            next_inertia=self.get_inertia(path[i][0],path[i+1][0])
            # if we switch directions, add the point, otherwise don't
            if prev_inertia!=next_inertia:
                newpath.append(path[i])

        # always add the last path unless it was a single point
        if len(path)>1:
            newpath.append(path[-1])
        return newpath
    

            
    def run_router(self, detour_scale):
        """
        This assumes the blockages, source, and target are all set up. 
        """
        # returns the path in tracks
        (path,cost) = self.rg.route(detour_scale)
        if path:
            debug.info(2,"Found path: cost={0} ".format(cost))
            debug.info(3,str(path))
            
            self.paths.append(path)
            self.add_route(path)
            
            path_set = grid_utils.flatten_set(path)
            self.path_blockages.append(path_set)
        else:
            self.write_debug_gds("failed_route.gds")
            # clean up so we can try a reroute
            self.rg.reinit()
            return False
        return True


    def annotate_pin_and_tracks(self, pin, tracks):
        """"
        Annotate some shapes for debug purposes
        """
        debug.info(0,"Annotating\n  pin {0}\n  tracks {1}".format(pin,tracks))
        for coord in tracks:
            (ll,ur) = self.convert_track_to_shape(coord)
            self.cell.add_rect(layer="text",
                               offset=ll,
                               width=ur[0]-ll[0],
                               height=ur[1]-ll[1])
            (ll,ur) = self.convert_track_to_pin(coord).rect
            self.cell.add_rect(layer="boundary",
                               offset=ll,
                               width=ur[0]-ll[0],
                               height=ur[1]-ll[1])
            (ll,ur) = pin.rect
            self.cell.add_rect(layer="text",
                               offset=ll,
                               width=ur[0]-ll[0],
                               height=ur[1]-ll[1])

    def write_debug_gds(self, gds_name="debug_route.gds", stop_program=True):
        """ 
        Write out a GDS file with the routing grid and search information annotated on it.
        """
        debug.info(0,"Writing annotated router gds file to {}".format(gds_name))
        self.add_router_info()
        self.cell.gds_write(gds_name)

        if stop_program:
            import sys
            sys.exit(1)

    def annotate_grid(self, g):
        """
        Display grid information in the GDS file for a single grid cell.
        """
        shape = self.convert_track_to_shape(g)
        partial_track=vector(0,self.track_width/6.0)
        self.cell.add_rect(layer="text",
                           offset=shape[0],
                           width=shape[1].x-shape[0].x,
                           height=shape[1].y-shape[0].y)
        t=self.rg.map[g].get_type()
                
        # midpoint offset
        off=vector((shape[1].x+shape[0].x)/2,
                   (shape[1].y+shape[0].y)/2)
        if t!=None:
            if g[2]==1:
                # Upper layer is upper right label
                type_off=off+partial_track
            else:
                # Lower layer is lower left label
                type_off=off-partial_track
            self.cell.add_label(text=str(t),
                                layer="text",
                                offset=type_off)

        t=self.rg.map[g].get_cost()
        partial_track=vector(self.track_width/6.0,0) 
        if t!=None:
            if g[2]==1:
                # Upper layer is right label
                type_off=off+partial_track
            else:
                # Lower layer is left label
                type_off=off-partial_track
            self.cell.add_label(text=str(t),
                                layer="text",
                                offset=type_off)
            
        self.cell.add_label(text="{0},{1}".format(g[0],g[1]),
                            layer="text",
                            offset=shape[0],
                            zoom=0.05)

    def add_router_info(self):
        """
        Write the routing grid and router cost, blockage, pins on 
        the boundary layer for debugging purposes. This can only be 
        called once or the labels will overlap.
        """
        debug.info(0,"Adding router info")

        show_blockages = False
        show_blockage_grids = False
        show_enclosures = False
        show_all_grids = True
        
        if show_all_grids:
            self.rg.add_all_grids()
            for g in self.rg.map.keys():
                self.annotate_grid(g)
            
        if show_blockages:
            # Display the inflated blockage
            for blockage in self.blockages:
                debug.info(1,"Adding {}".format(blockage))
                (ll,ur) = blockage.inflate()
                self.cell.add_rect(layer="text",
                                   offset=ll,
                                   width=ur.x-ll.x,
                                   height=ur.y-ll.y)
        if show_blockage_grids:
            self.set_blockages(self.blocked_grids,True)
            grid_keys=self.rg.map.keys()
            for g in grid_keys:
                self.annotate_grid(g)

        if show_enclosures:
            for key in self.pin_groups.keys():
                for pg in self.pin_groups[key]:
                    if not pg.enclosed:
                        continue
                    for pin in pg.enclosures:
                        #print("enclosure: ",pin.name,pin.ll(),pin.width(),pin.height())
                        self.cell.add_rect(layer="text",
                                           offset=pin.ll(),
                                           width=pin.width(),
                                           height=pin.height())
    
# FIXME: This should be replaced with vector.snap_to_grid at some point

def snap_to_grid(offset):
    """
    Changes the coodrinate to match the grid settings
    """
    xoff = snap_val_to_grid(offset[0])
    yoff = snap_val_to_grid(offset[1])    
    return vector(xoff, yoff)

def snap_val_to_grid(x):
    grid = drc("grid")
    xgrid = int(round(round((x / grid), 2), 0))
    xoff = xgrid * grid
    return xoff