# Can pennylane support parallel simulation on multi CPUs simultaneously?

**URL:** <https://discuss.pennylane.ai/t/can-pennylane-support-parallel-simulation-on-multi-cpus-simultaneously/1008>\
**Category:** PennyLane Help\
**Created:** [April 29, 2021, 2:51pm UTC](https://discuss.pennylane.ai/t/can-pennylane-support-parallel-simulation-on-multi-cpus-simultaneously/1008 "2021-04-29T14:51:20Z")\
**Posts on this page:** 1\
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**Author:** ![sjahangiri](https://yyz2.discourse-cdn.com/flex012/user_avatar/discuss.pennylane.ai/sjahangiri/32/1443_2.png) [@sjahangiri](https://discuss.pennylane.ai/u/sjahangiri)\
**Post date:** [April 29, 2021, 7:48pm UTC](https://discuss.pennylane.ai/t/can-pennylane-support-parallel-simulation-on-multi-cpus-simultaneously/1008/2 "2021-04-29T19:48:02Z")

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Hi @Yang and welcome to the forum!

You can use the [QnodeCollection](https://pennylane.readthedocs.io/en/stable/code/api/pennylane.QNodeCollection.html) class to create a collection of independent Qnodes that can be simultaneously evaluated. The collection can be created as:

`qnode = qml.QNodeCollection([qnode1, qnode2])`

The qnodes within the QNodeCollection are executed sequentially by default but you can use the `parallel=True` keyword argument to activate asynchronous evaluation. However, the best speedup is achieved with external hardware devices or external simulators as explained in further details [here](https://pennylane.readthedocs.io/en/stable/code/api/pennylane.QNodeCollection.html) under the “Asynchronous Evaluation” section. You may also find this previous [discussion](http://discuss.pennylane.ai/t/multiprocessing-for-simulator-devices/827) helpful. Please feel free to let us know if you have any further questions.

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