# \#multithreading **URL:** https://itensor.discourse.group/tag/multithreading/4.md [Latest](https://itensor.discourse.group/latest.md) · [Categories](https://itensor.discourse.group/categories.md) · [Tags](https://itensor.discourse.group/tags.md) --- ## [Multi threading in ITensor](https://itensor.discourse.group/t/multi-threading-in-itensor/2531)
**Author:** [@tamoghnaRay](https://itensor.discourse.group/u/tamoghnaRay)\ **Replies:** 10\ **Last updated:** [November 20, 2025, 3:41pm UTC](https://itensor.discourse.group/t/multi-threading-in-itensor/2531 "2025-11-20T15:41:53Z")
Hi, I am doing a TEBD computation on an HPC, and I want to understand how to use multithreading effectively. I am using QN conserving systems. Following the instructions in the multithreading page of the documentation, … --- ## [Proper Environment Variables for Managing MKL and Julia Threads](https://itensor.discourse.group/t/proper-environment-variables-for-managing-mkl-and-julia-threads/2305)
**Author:** [@swanchristmas](https://itensor.discourse.group/u/swanchristmas)\ **Replies:** 1\ **Last updated:** [March 14, 2025, 2:43pm UTC](https://itensor.discourse.group/t/proper-environment-variables-for-managing-mkl-and-julia-threads/2305 "2025-03-14T14:43:11Z")
I’m encountering conflicting threading behavior when running DMRG calculations with Julia (v1.11.3) and MKL. Despite efforts to limit thread counts, CPU usage spikes to ~2000% with degraded performance. Here are key obse… --- ## [Issues using Block Sparse Multithreading](https://itensor.discourse.group/t/issues-using-block-sparse-multithreading/1996)
**Author:** [@LuanSS](https://itensor.discourse.group/u/LuanSS)\ **Replies:** 4\ **Last updated:** [October 2, 2024, 7:05pm UTC](https://itensor.discourse.group/t/issues-using-block-sparse-multithreading/1996 "2024-10-02T19:05:37Z")
Hello, This is my first question here in the ITensor and english isn’t my native language, so sorry for any English mistake. So i am performing some Quantum Number Conserving DMRG calculations, and i used the ITensors.… --- ## [ITensor Multithreading for Dense MPS](https://itensor.discourse.group/t/itensor-multithreading-for-dense-mps/1443)
**Author:** [@Bob](https://itensor.discourse.group/u/Bob)\ **Replies:** 1\ **Last updated:** [January 24, 2024, 3:55pm UTC](https://itensor.discourse.group/t/itensor-multithreading-for-dense-mps/1443 "2024-01-24T15:55:21Z")
Hello, I am making this post as a following from here. A bit of context first. I am not a multithreading expert. I have used it a few times before with other languages so I am familiar with the basics of what it is but… --- ## [MPS time evolution, apply function (julia) much slower than gateTEvol (c++)](https://itensor.discourse.group/t/mps-time-evolution-apply-function-julia-much-slower-than-gatetevol-c/1131)
**Author:** [@iChaker](https://itensor.discourse.group/u/iChaker)\ **Replies:** 8\ **Last updated:** [October 6, 2023, 2:46pm UTC](https://itensor.discourse.group/t/mps-time-evolution-apply-function-julia-much-slower-than-gatetevol-c/1131 "2023-10-06T14:46:33Z")
I am trying to run time evolution on an MPS, but I noticed that Julia is much slower than c++. To confirm this I used the example codes provided in the documentation that implement TEBD on a one-dimensional Heisenberg mo… --- ## [evaluating overlaps of MPSs in parallel](https://itensor.discourse.group/t/evaluating-overlaps-of-mpss-in-parallel/451)
**Author:** [@virgil](https://itensor.discourse.group/u/virgil)\ **Replies:** 3\ **Last updated:** [October 10, 2022, 3:31pm UTC](https://itensor.discourse.group/t/evaluating-overlaps-of-mpss-in-parallel/451 "2022-10-10T15:31:20Z")
Hi, I’m trying to construct the overlap matrix of an array of MPSs, and since it is an embarrassingly parallel problem I hoped to get a substantial improvement in the execution time by using Threads. However, this is no… --- ## [Some problems about MPI Parallelism](https://itensor.discourse.group/t/some-problems-about-mpi-parallelism/44)
**Author:** [@SugarYu](https://itensor.discourse.group/u/SugarYu)\ **Replies:** 3\ **Last updated:** [April 17, 2022, 5:20pm UTC](https://itensor.discourse.group/t/some-problems-about-mpi-parallelism/44 "2022-04-17T17:20:11Z")
Dear ITensor team, Thanks for your reply and thanks for the wonderful library about TensorNetwork. Recently, i perform some DMRG calculations with MPI parallelism. I have a question about MPI parallelism I am using th… --- ## [Block sparse multithreading warning](https://itensor.discourse.group/t/block-sparse-multithreading-warning/41)
**Author:** [@navya](https://itensor.discourse.group/u/navya)\ **Replies:** 1\ **Last updated:** [April 15, 2022, 8:01pm UTC](https://itensor.discourse.group/t/block-sparse-multithreading-warning/41 "2022-04-15T20:01:48Z")
Excited to be on this new discussion forum! I had a question about implementing block sparse multithreading in Julia. My system has 8 threads available. On the terminal, I start Julia using julia -t 8 so that it uses al…