Overview
Intel® MPI Library for Windows OS* is a high-performance interconnect-independent multi-fabric library implementation of the industry-standard Message Passing Interface, v4.1 (MPI-4.1).
To receive technical support and updates, you need to register your product copy. See Technical Support below.
Key Features
This release of the Intel(R) MPI Library supports the following major features:
- MPI-1, MPI-2.2, MPI-3.1, MPI 4.0, MPI 4.1 and MPI 5.0 (technical preview)
- Interconnect independence
- C, C++, Fortran 77, Fortran 90 and Fortran 2008 language bindings
- Amazon* AWS/EFA, Google* GCP support
Product Contents
- The Intel® MPI Library Runtime Environment (RTE) contains the tools you need to run programs including scalable process management system (Hydra), supporting utilities, and dynamic libraries.
- The Intel® MPI Library Development Kit (SDK) includes all of the Runtime Environment components and compilation tools: compiler wrapper scripts, include files and modules, debug libraries, and test codes.
You can redistribute the library under conditions specified in the License.
Intel® MPI Library 2021 Update 19.0 - oneAPI 2026.2
What's New
- Libfabric is no longer packaged within the Intel® MPI installation tree and is instead shipped as a separate oneAPI component. In standalone Intel® MPI installations, libfabric is still installed alongside Intel® MPI for convenience, but it is not part of the Intel® MPI directory layout in the same way as before.
- I_MPI_OFI_INTERNAL is deprecated
- Tuning for single-node and multi-node all-to-all algorithms
- Platform recognition and shm transport support for upcoming Intel® CPU platforms
- Technical preview of a new CBWR mode, I_MPI_CBWR=3. Currently the implementation only supports MPI_ALLREDUCE together with MPI_SUM and MPI_DOUBLE or MPI_DOUBLE_PRECISION
- On Windows the variable I_MPI_PIN_RESPECT_INHERITANCE=0/1 is introduced to control the process prinning inheritance of child processes
- Bug fixes
Known Issues and Limitations
-
Additional steps for pip installation
To install Intel® MPI Library 2021.19.0 (or any package that depends on it) from PyPi using pip, please install libfabric first from Intel repository:
pip install libfabric --index-url https://software.repos.intel.com/python/pypi
Then install the component you need, e.g.:
pip install impi_devel==2021.19.0Not installing libfabric first will lead to an unresolved dependency error.
Installation without a version specifier (==) will install the highest available version for which all dependencies are resolved. - When you run an MPI program on a single node and do not enable process spawning (I_MPI_SPAWN is not set to 1), the MPI runtime automatically enables Intel® MPI shared memory for communication (I_MPI_FABRICS=shm). However, shared‑memory mode is incompatible with the MPI Spawn APIs. If your application uses MPI_Comm_spawn (or related spawn functions) while I_MPI_FABRICS=shm is active, the program will terminate with an error. To avoid this issue, you must explicitly enable spawning by setting: I_MPI_SPAWN=1 before running your application.
- When using thread split functionality with the new implicit mode, ensure that
- Application follows the semantics of the MPI_THREAD_SPLIT communication model.
- Set I_MPI_THREAD_MAX=<N> to the number of threads per rank, along with I_MPI_THREAD_SPLIT=1 and I_MPI_THREAD_SPLIT_MODE=implicit.
- Server Message Block (SMB) shares may be unavailable for MPI processes in case of powershell bootstrap (out-of-box behavior). Consider Network File System (NFS) usage or domain-based authorization for this case.
System Requirements
Hardware Requirements
-
Systems based on the Intel® 64 architecture, in particular:
- Intel® Core™ processor family or higher
- Intel® Xeon® Scalable processor family
- Intel® Xeon® 6 processor family
- 1 GB of RAM per rank (2 GB recommended)
- 1 GB of free hard disk space
Software Requirements
Windows* OS
-
Microsoft* Windows* Server 2019, 2022, 2025
- Microsoft* Windows* 10, 11
(SDK only) Compilers
- Intel® C++/Fortran Compiler 17.0 or newer
- Microsoft* Visual Studio* Compilers 2022
Batch systems
- Microsoft* Job Scheduler
- Altair* PBS Pro* 9.2 or newer
Fabric software
- Open Fabric Interface (OFI): https://github.com/ofiwg/libfabric
- Minimum: OFI 2.6.0
- Recommend to use OFI provided with IMPI
Supported languages
- For GNU* compilers: C, C++, Fortran
- For Intel® compilers: C, C++, Fortran
Legal Information
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Your costs and results may vary.
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The products described may contain design defects or errors known as errata which may cause the product to deviate from published specifications. Current characterized errata are available on request.
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Technical Support
Every purchase of an Intel® Software Development Product includes a year of support services, which provides Priority Support at our Online Service Center web site.
In order to get support you need to register your product in the Intel® Registration Center. If your product is not registered, you will not receive Priority Support.
Additional Resources