Move Cirq-FT infrastructure to Qualtran

qualtran/__init__.py

@@ -58,4 +58,6 @@
     Soquet,
 )
 
+from ._infra.gate_with_registers import GateWithRegisters
+
 # --------------------------------------------------------------------------------------------------

qualtran/_infra/gate_with_registers.ipynb

@@ -0,0 +1,244 @@
+{
+ "cells": [
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "3b990f88",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Copyright 2023 The Cirq Developers\n",
+    "#\n",
+    "# Licensed under the Apache License, Version 2.0 (the \"License\");\n",
+    "# you may not use this file except in compliance with the License.\n",
+    "# You may obtain a copy of the License at\n",
+    "#\n",
+    "#     https://www.apache.org/licenses/LICENSE-2.0\n",
+    "#\n",
+    "# Unless required by applicable law or agreed to in writing, software\n",
+    "# distributed under the License is distributed on an \"AS IS\" BASIS,\n",
+    "# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.\n",
+    "# See the License for the specific language governing permissions and\n",
+    "# limitations under the License."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "bf9c80ce",
+   "metadata": {},
+   "source": [
+    "# Gate with Registers\n",
+    "\n",
+    "This package includes a subclass of `cirq.Gate` called `GateWithRegisters`. Instead of operating on a flat list of `cirq.Qid`, this lets the developer define gates in terms of named registers of given widths."
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "c0833444",
+   "metadata": {},
+   "source": [
+    "## `Signature`\n",
+    "\n",
+    "`Register` objects have a name, a bitsize and a shape. `Signature` is an ordered collection of `Register` with some helpful methods."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "c75414f2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from qualtran import Register, Signature\n",
+    "\n",
+    "control_reg = Register(name='control', bitsize=2)\n",
+    "target_reg = Register(name='target', bitsize=3)\n",
+    "control_reg, target_reg"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b38d210c",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "r = Signature([control_reg, target_reg])\n",
+    "r"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "2b32274b",
+   "metadata": {},
+   "source": [
+    "You can also use the `build` factory method to quickly define a set of registers"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "4f10e66e",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "r == Signature.build(\n",
+    "    control=2,\n",
+    "    target=3,\n",
+    ")"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "a5955208",
+   "metadata": {},
+   "source": [
+    "### `GateWithRegisters`"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "b3957db4",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import cirq\n",
+    "from qualtran import GateWithRegisters\n",
+    "\n",
+    "class MyGate(GateWithRegisters):\n",
+    "    \n",
+    "    @property\n",
+    "    def signature(self):\n",
+    "        return Signature.build(\n",
+    "            control=2,\n",
+    "            target=3,\n",
+    "        )\n",
+    "    \n",
+    "    def decompose_from_registers(self, context, control, target):\n",
+    "        assert len(control) == 2\n",
+    "        assert len(target) == 3\n",
+    "        \n",
+    "        for c in control:\n",
+    "            for t in target:\n",
+    "                yield cirq.CNOT(c, t)\n",
+    "        "
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "2de931eb",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "gate = MyGate()\n",
+    "gate"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "ef98f3a2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "# Number of qubits is derived from registers\n",
+    "cirq.num_qubits(gate)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "2d725646",
+   "metadata": {},
+   "source": [
+    "The `Signature` object can allocate a dictionary of `cirq.NamedQubit` that we can use to turn our `Gate` into an `Operation`. `GateWithRegisters` exposes an `on_registers` method to compliment Cirq's `on` method where we can use names to make sure each qubit is used appropriately."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "057148da",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from qualtran._infra.gate_with_registers import get_named_qubits\n",
+    "\n",
+    "r = gate.signature\n",
+    "quregs = get_named_qubits(r)\n",
+    "quregs"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "0257d8f1",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "operation = gate.on_registers(**quregs)\n",
+    "operation"
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "541f2e91",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "from cirq.contrib.svg import SVGCircuit\n",
+    "SVGCircuit(cirq.Circuit(operation))"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "6686f7f8",
+   "metadata": {},
+   "source": [
+    "## `GateHelper`\n",
+    "\n",
+    "Since `GateWithRegisters` contains enough metadata to derive qubits, an operation, and a circuit we provide a helper class to provide easy access to these quantities."
+   ]
+  },
+  {
+   "cell_type": "code",
+   "execution_count": null,
+   "id": "93a6c8f2",
+   "metadata": {},
+   "outputs": [],
+   "source": [
+    "import qualtran.cirq_interop.testing as cq_testing\n",
+    "\n",
+    "g = cq_testing.GateHelper(gate)\n",
+    "\n",
+    "print('r:', g.r)\n",
+    "print('quregs:', g.quregs)\n",
+    "print('operation:', g.operation)\n",
+    "print('\\ncircuit:\\n', g.circuit)\n",
+    "print('\\n\\ndecomposed circuit:\\n', cirq.Circuit(cirq.decompose_once(g.operation)))"
+   ]
+  }
+ ],
+ "metadata": {
+  "kernelspec": {
+   "display_name": "Python 3",
+   "language": "python",
+   "name": "python3"
+  },
+  "language_info": {
+   "codemirror_mode": {
+    "name": "ipython",
+    "version": 3
+   },
+   "file_extension": ".py",
+   "mimetype": "text/x-python",
+   "name": "python",
+   "nbconvert_exporter": "python",
+   "pygments_lexer": "ipython3",
+   "version": "3.8.16"
+  }
+ },
+ "nbformat": 4,
+ "nbformat_minor": 5
+}