W node support

pyzx/basicrules.py

@@ -47,7 +47,8 @@
 
 from typing import Tuple, List
 from .graph.base import BaseGraph, VT, ET
-from .utils import VertexType, EdgeType, is_pauli
+from .rules import apply_rule, w_fusion
+from .utils import VertexType, EdgeType, get_w_io, is_pauli, vertex_is_w
 
 def color_change_diagram(g: BaseGraph[VT,ET]):
     """Color-change an entire diagram by applying Hadamards to the inputs and ouputs."""
@@ -95,8 +96,8 @@ def check_strong_comp(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
     return True
 
 def strong_comp(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
-    if not check_strong_comp(g, v1, v2): return False    
-    
+    if not check_strong_comp(g, v1, v2): return False
+
     nhd: Tuple[List[VT],List[VT]] = ([],[])
     v = (v1,v2)
 
@@ -121,7 +122,7 @@ def strong_comp(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
 
     g.remove_vertex(v1)
     g.remove_vertex(v2)
-    
+
     return True
 
 def check_copy_X(g: BaseGraph[VT,ET], v: VT) -> bool:
@@ -136,10 +137,10 @@ def check_copy_X(g: BaseGraph[VT,ET], v: VT) -> bool:
     return True
 
 def copy_X(g: BaseGraph[VT,ET], v: VT) -> bool:
-    if not check_copy_X(g, v): return False    
+    if not check_copy_X(g, v): return False
     nv = next(iter(g.neighbors(v)))
     strong_comp(g, v, nv)
-    
+
     return True
 
 def check_pi_commute_Z(g: BaseGraph[VT, ET], v: VT) -> bool:
@@ -163,7 +164,7 @@ def pi_commute_Z(g: BaseGraph[VT, ET], v: VT) -> bool:
             g.add_edge(g.edge(v, c))
             g.add_edge(g.edge(c, w), edgetype=et)
     return True
-    
+
 def check_pi_commute_X(g: BaseGraph[VT,ET], v: VT) -> bool:
     color_change_diagram(g)
     b = check_pi_commute_Z(g, v)
@@ -189,24 +190,47 @@ def copy_Z(g: BaseGraph, v: VT) -> bool:
     return b
 
 def check_fuse(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
+    if check_fuse_w(g, v1, v2):
+        return True
     if not (g.connected(v1,v2) and
             ((g.type(v1) == VertexType.Z and g.type(v2) == VertexType.Z) or
              (g.type(v1) == VertexType.X and g.type(v2) == VertexType.X)) and
             g.edge_type(g.edge(v1,v2)) == EdgeType.SIMPLE):
         return False
-    else:
-        return True
+    return True
 
 def fuse(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
     if not check_fuse(g, v1, v2): return False
+    if vertex_is_w(g.type(v1)):
+        return fuse_w(g, v1, v2)
     g.add_to_phase(v1, g.phase(v2))
     for v3 in g.neighbors(v2):
         if v3 != v1:
             g.add_edge_smart(g.edge(v1,v3), edgetype=g.edge_type(g.edge(v2,v3)))
-
     g.remove_vertex(v2)
     return True
 
+def check_fuse_w(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
+    if vertex_is_w(g.type(v1)) and vertex_is_w(g.type(v2)):
+        v1_in, v1_out = get_w_io(g, v1)
+        v2_in, v2_out = get_w_io(g, v2)
+        if g.edge_type(g.edge(v1_in, v2_out)) == EdgeType.SIMPLE or \
+           g.edge_type(g.edge(v2_in, v1_out)) == EdgeType.SIMPLE:
+            return True
+    return False
+
+def fuse_w(g: BaseGraph[VT,ET], v1: VT, v2: VT) -> bool:
+    if not check_fuse_w(g, v1, v2): return False
+    v1_in, v1_out = get_w_io(g, v1)
+    v2_in, v2_out = get_w_io(g, v2)
+    if g.edge_type(g.edge(v1_out, v2_in)) == EdgeType.SIMPLE:
+        apply_rule(g, w_fusion, [(v1, v2)])
+    else:
+        g.set_position(v2_in, g.qubit(v1_in), g.row(v1_in))
+        g.set_position(v2_out, g.qubit(v1_out), g.row(v1_out))
+        apply_rule(g, w_fusion, [(v2, v1)])
+    return True
+
 def check_remove_id(g: BaseGraph[VT,ET], v: VT) -> bool:
     if not (g.vertex_degree(v) == 2 and g.phase(v) == 0):
         return False
@@ -216,13 +240,13 @@ def check_remove_id(g: BaseGraph[VT,ET], v: VT) -> bool:
 def remove_id(g: BaseGraph[VT,ET], v: VT) -> bool:
     if not check_remove_id(g, v):
         return False
-    
+
     v1, v2 = tuple(g.neighbors(v))
     g.add_edge_smart(g.edge(v1,v2), edgetype=EdgeType.SIMPLE
             if g.edge_type(g.edge(v,v1)) == g.edge_type(g.edge(v,v2))
             else EdgeType.HADAMARD)
     g.remove_vertex(v)
-    
+
     return True
 
 

pyzx/drawing.py

@@ -184,7 +184,7 @@ def draw_matplotlib(
     vs_on_row: Dict[FloatInt, int] = {} # count the vertices on each row
     for v in g.vertices():
         vs_on_row[g.row(v)] = vs_on_row.get(g.row(v), 0) + 1
-    
+
     #Dict[VT,Tuple[FloatInt,FloatInt]]
     layout = {v:(g.row(v),-g.qubit(v)) for v in g.vertices()}
 
@@ -195,18 +195,22 @@ def draw_matplotlib(
     else:
         vertices = g.vertices()
         edges = g.edges()
-    
+
     for e in edges:
         sp = layout[g.edge_s(e)]
         tp = layout[g.edge_t(e)]
         et = g.edge_type(e)
         n_row = vs_on_row.get(g.row(g.edge_s(e)), 0)
 
-
         dx = tp[0] - sp[0]
         dy = tp[1] - sp[1]
         bend_wire = (dx == 0) and h_edge_draw == 'blue' and n_row > 2
-        ecol = '#0099ff' if h_edge_draw == 'blue' and et == 2 else 'black'
+        if et == 2 and h_edge_draw == 'blue':
+            ecol = '#0099ff'
+        elif et == 3:
+            ecol = 'gray'
+        else:
+            ecol = 'black'
 
         if bend_wire:
             bend = 0.25
@@ -231,7 +235,7 @@ def draw_matplotlib(
             ax.add_patch(patches.Rectangle(centre,w,h,angle=angle/math.pi*180,facecolor='yellow',edgecolor='black'))
 
         #plt.plot([sp[0],tp[0]],[sp[1],tp[1]], 'k', zorder=0, linewidth=0.8)
-    
+
     for v in vertices:
         p = layout[v]
         t = g.type(v)
@@ -245,12 +249,16 @@ def draw_matplotlib(
         elif t == VertexType.H_BOX:
             ax.add_patch(patches.Rectangle((p[0]-0.1, p[1]-0.1), 0.2, 0.2, facecolor='yellow', edgecolor='black'))
             a_offset = 0.25
+        elif t == VertexType.W_INPUT:
+            ax.add_patch(patches.Circle(p, 0.05, facecolor='black', edgecolor='black', zorder=1))
+        elif t == VertexType.W_OUTPUT:
+            ax.add_patch(patches.Polygon([(p[0]-0.15, p[1]), (p[0]+0.15, p[1]+0.2), (p[0]+0.15, p[1]-0.2)], facecolor='black', edgecolor='black'))
         else:
             ax.add_patch(patches.Circle(p, 0.1, facecolor='black', edgecolor='black', zorder=1))
 
         if labels: plt.text(p[0]+0.25, p[1]+0.25, str(v), ha='center', color='gray', fontsize=5)
         if a: plt.text(p[0], p[1]-a_offset, phase_to_s(a, t), ha='center', color='blue', fontsize=8)
-    
+
     if show_scalar:
         x = min((g.row(v) for v in g.vertices()), default = 0)
         y = -sum((g.qubit(v) for v in g.vertices()))/(g.num_vertices()+1)

pyzx/editor_actions.py

@@ -330,6 +330,11 @@ def bialgebra(g: BaseGraph[VT,ET],
                "matcher": hrules.match_par_hbox, 
                "rule": hrules.par_hbox, 
                "type": MATCHES_VERTICES},
+    "fuse_w": {"text": "fuse W nodes",
+               "tooltip": "Merges two connected W nodes together",
+               "matcher": rules.match_w_fusion_parallel,
+                "rule": rules.w_fusion,
+                "type": MATCHES_EDGES},
     "copy": {"text": "copy 0/pi spider", 
                "tooltip": "Copies a single-legged spider with a 0/pi phase through its neighbor",
                "matcher": hrules.match_copy, 

pyzx/generate.py

@@ -39,7 +39,7 @@
 from pyzx.routing.parity_maps import CNOT_tracker, Parity
 from pyzx.routing.phase_poly import PhasePoly, mat22partition
 
-from .utils import EdgeType, VertexType, FloatInt, FractionLike
+from .utils import EdgeType, VertexType, FloatInt, FractionLike, vertex_is_w
 from .graph import Graph
 from .graph.base import BaseGraph
 from .circuit import Circuit
@@ -70,7 +70,7 @@ def identity(qubits: int, depth: FloatInt=1,backend:Optional[str]=None) -> BaseG
     return g
 
 def spider(
-    typ:Union[Literal["Z"],Literal["X"],Literal["H"],VertexType.Type],
+    typ:Union[Literal["Z"], Literal["X"], Literal["H"], Literal["W"], VertexType.Type],
     inputs: int,
     outputs: int,
     phase:FractionLike=0
@@ -80,10 +80,20 @@ def spider(
     if typ == "Z": typ = VertexType.Z
     elif typ == "X": typ = VertexType.X
     elif typ == "H": typ = VertexType.H_BOX
+    elif typ == "W": typ = VertexType.W_OUTPUT
     else:
-        if not isinstance(typ,int):
+        if not isinstance(typ, int):
             raise TypeError("Wrong type for spider type: " + str(typ))
     g = Graph()
+    if vertex_is_w(typ):
+        if inputs != 1:
+            raise ValueError("Wrong number of inputs for W node: " + str(inputs))
+        v_in = g.add_vertex(VertexType.W_INPUT, (outputs-1)/2, 0.8)
+        v_out = g.add_vertex(VertexType.W_OUTPUT, (outputs-1)/2, 1)
+        g.add_edge(g.edge(v_in, v_out), EdgeType.W_IO)
+    else:
+        v_in = g.add_vertex(typ, (inputs-1)/2, 1, phase)
+        v_out = v_in
     inp = []
     outp = []
     for i in range(inputs):
@@ -92,11 +102,10 @@ def spider(
     for i in range(outputs):
         v = g.add_vertex(VertexType.BOUNDARY,i,2)
         outp.append(v)
-    v = g.add_vertex(typ,(inputs-1)/2,1,phase)
     for w in inp:
-        g.add_edge(g.edge(v,w))
+        g.add_edge(g.edge(v_in, w))
     for w in outp:
-        g.add_edge(g.edge(v,w))
+        g.add_edge(g.edge(v_out, w))
 
     g.set_inputs(tuple(inp))
     g.set_outputs(tuple(outp))
@@ -105,13 +114,13 @@ def spider(
 
 
 def CNOT_HAD_PHASE_circuit(
-        qubits: int, 
-        depth: int, 
-        p_had: float = 0.2, 
-        p_t: float = 0.2, 
+        qubits: int,
+        depth: int,
+        p_had: float = 0.2,
+        p_t: float = 0.2,
         clifford:bool=False
         ) -> Circuit:
-    """Construct a Circuit consisting of CNOT, HAD and phase gates. 
+    """Construct a Circuit consisting of CNOT, HAD and phase gates.
     The default phase gate is the T gate, but if ``clifford=True``\ , then
     this is replaced by the S gate.