Improved splitIntoBlocks

Author: perak

lib/quantum-circuit.js

@@ -4426,7 +4426,8 @@ QuantumCircuit.prototype.validCustomGateName = function(baseName) {
 //
 // Options:
 //   {
-//     flexibleBlockSize: bool // Allow larger blocks for gates with more qubits than block size
+//      flexibleBlockSize: bool // Allow larger blocks for gates with more qubits than block size
+//      verticalOnly: bool // Don't extend blocks horizontally
 //   }
 //
 
@@ -4446,9 +4447,8 @@ QuantumCircuit.prototype.splitIntoBlocks = function(blockSize, options) {
 	for(var column = 0; column < numCols; column++) {
 		for(var wire = 0; wire < decomposed.numQubits; wire++) {
 			var gate = decomposed.getGateAt(column, wire);
-			if(gate && gate.connector == 0) {
+			if(gate && gate.connector == 0 && !gate.addedToBlock) {
 				var gateDef = this.basicGates[gate.name];
-
 				var currentCondition = gate.options && gate.options.condition ? JSON.stringify(gate.options.condition) : "{}";
 				var currentIsUnitary = gateDef && !!(gateDef.matrix && gateDef.matrix.length);
 
@@ -4480,8 +4480,78 @@ QuantumCircuit.prototype.splitIntoBlocks = function(blockSize, options) {
 					currentBlock.gates.push(gate);
 				}
 
+				gate.wires.map(function(ww) {
+					decomposed.gates[ww][column].addedToBlock = true;
+				});
+
 				prevCondition = currentCondition;
 				prevIsUnitary = currentIsUnitary;
+
+				if(!options.verticalOnly) {
+					// try to extend the block horizontally
+					var extColumn = column + 1;
+					var extWires = JSON.parse(JSON.stringify(currentBlock.wires));
+					extWires.sort();
+					while(extColumn < numCols && extWires.length) {
+						extWire = extWires[0];
+
+						while(extWires.length && extWire <= extWires[extWires.length - 1]) {
+							var extGate = decomposed.getGateAt(extColumn, extWire);
+							if(extGate && !extGate.addedToBlock) {
+								var extGateDef = this.basicGates[extGate.name];
+								var extCondition = extGate.options && extGate.options.condition ? JSON.stringify(extGate.options.condition) : "{}";
+								var extIsUnitary = extGateDef && !!(extGateDef.matrix && extGateDef.matrix.length);
+
+								//
+								// Check if gate is valid for block
+								//
+								var gateValid = extIsUnitary && (extCondition == currentCondition);
+
+								// Check if all gate's wires are inside block
+								if(gateValid) {
+									for(var ww = 0; ww < extGate.wires.length; ww++) {
+										if(extWires.indexOf(extGate.wires[ww]) < 0) {
+											gateValid = false;
+											break;
+										}
+									}
+								}
+
+								if(gateValid) {
+									// add gate to block
+									currentBlock.gates.push(extGate);
+
+									extGate.wires.map(function(ww) {
+										decomposed.gates[ww][extColumn].addedToBlock = true;
+									});
+								} else {
+									// remove gate's wires from scan
+									var validExtWires = [];
+									for(var ww = 0; ww < extWires.length; ww++) {
+										var extW = extWires[ww];
+										if(extGate.wires.indexOf(extW) < 0) {
+											validExtWires.push(extW);
+										}
+									}
+									extWires = validExtWires;
+								}
+							}
+							// goto next valid wire
+							if(extWires.length) {
+								var newExtWire = extWires[extWires.length - 1] + 1;
+								for(var ww = extWires.length - 1; ww >= 0; ww--) {
+									var extW = extWires[ww];
+									if(extW > extWire) {
+										newExtWire = extW;
+									}
+								}
+								extWire = newExtWire;
+							}
+
+						}
+						extColumn++;
+					}
+				}
 			}
 		}
 	}