Simulator

This quantum executor introduces thread- or process-based parallelism to Pennylane circuits that utilize simulation-based devices (like "default.qubit" or "lightning.qubit").

1. Installation

No additional installation is required.

2. Usage Example

A thread-based Simulator is the default quantum executor for QElectrons.

import covalent as ct
import pennylane as qml

@ct.qelectron
@qml.qnode(qml.device("lightning.qubit", wires=2), interface="torch")
def circuit(x):
    qml.IQPEmbedding(features=x, wires=[0, 1])
    qml.Hadamard(wires=1)
    return qml.probs(wires=range(2))

Once converted to a QElectron, the circuit can be called either normally or asynchronously via circuit.run_later().

A synchronous example is show below.

>>> circuit([1.3, -0.7]), circuit([1.3, -0.7])

(tensor([0.3169, 0.3169, 0.1831, 0.1831], dtype=torch.float64),
 tensor([0.3169, 0.3169, 0.1831, 0.1831], dtype=torch.float64))

Alternatively, doing this asynchronously:

>>> # Use separate threads to run two circuits simultaneously.
>>> futs = [circuit.run_later([1.3, -0.7]) for _ in range(2)]

# Wait for all circuits to finish.
>>> [fut.result() for fut in futs]

[tensor([0.3169, 0.3169, 0.1831, 0.1831], dtype=torch.float64),
 tensor([0.3169, 0.3169, 0.1831, 0.1831], dtype=torch.float64)]

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pydantic model covalent.executor.Simulator

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A quantum executor that uses the specified Pennylane device to execute circuits. Parallelizes circuit execution on the specified device using either threads or processes.

Keyword Arguments

device (str)

A valid string corresponding to a Pennylane device. Simulation-based devices (e.g. “default.qubit” and “lightning.qubit”) are recommended. Defaults to “default.qubit”.

parallel (str)

The type of parallelism to use. Valid values are “thread” and “process”. Passing any other value will result in synchronous execution. Defaults to “thread”.

workers (int)

The number of threads or processes to use. Defaults to 10.

shots (int)

The number of shots to use for the execution device. Overrides the shots value from the original device if set to None or a positive int. The shots setting from the original device is used by default when this argument is 0.

Show JSON Schema

{
   "title": "Simulator",
   "description": "A quantum executor that uses the specified Pennylane device to execute circuits.\nParallelizes circuit execution on the specified `device` using either threads\nor processes.\n\nKeyword Args:\n    device: A valid string corresponding to a Pennylane device. Simulation-based \n        devices (e.g. \"default.qubit\" and \"lightning.qubit\") are recommended.\n        Defaults to \"default.qubit\".\n    parallel: The type of parallelism to use. Valid values are \"thread\" and\n        \"process\". Passing any other value will result in synchronous execution.\n        Defaults to \"thread\".\n    workers: The number of threads or processes to use. Defaults to 10.\n    shots: The number of shots to use for the execution device. Overrides the\n        :code:`shots` value from the original device if set to :code:`None` or\n        a positive :code:`int`. The shots setting from the original device is\n        is used by default, when this argument is 0.",
   "type": "object",
   "properties": {
      "persist_data": {
         "title": "Persist Data",
         "default": true,
         "type": "boolean"
      },
      "qnode_device_import_path": {
         "title": "Qnode Device Import Path",
         "type": "array",
         "minItems": 2,
         "maxItems": 2,
         "items": [
            {
               "type": "string"
            },
            {
               "type": "string"
            }
         ]
      },
      "qnode_device_shots": {
         "title": "Qnode Device Shots",
         "type": "integer"
      },
      "qnode_device_wires": {
         "title": "Qnode Device Wires",
         "type": "integer"
      },
      "pennylane_active_return": {
         "title": "Pennylane Active Return",
         "type": "boolean"
      },
      "device": {
         "title": "Device",
         "default": "default.qubit",
         "type": "string"
      },
      "parallel": {
         "title": "Parallel",
         "default": "thread",
         "anyOf": [
            {
               "type": "boolean"
            },
            {
               "type": "string"
            }
         ]
      },
      "workers": {
         "title": "Workers",
         "default": 10,
         "type": "integer"
      },
      "shots": {
         "title": "Shots",
         "default": 0,
         "type": "integer"
      }
   }
}

CONFIG

extra: EXTRA = allow

field device: str = 'default.qubit'

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Validated by

set_name

field parallel: Union[bool, str] = 'thread'

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Validated by

set_name

field shots: int = 0

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Validated by

set_name

field workers: int = 10

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Validated by

set_name

batch_get_results

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batch_submit

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[source]