1 This document describes the Message-Passing Interface(MPI)standard,version 4.0. 2 The MPIstandard includes p oint-to-point ollective nicator concepts mmunication nd ntal ,grou ana ation and manage opolo ent.proce ided com tended collectiv eration interfaces.I/o.】 eoustopics,and multiple tool interfaces.Language binding for C and Fortra re defined 7 of the standard s MPI-10(MP1 ddition to MPI-2.0 (July 18,1997),with 10 onts 1.1 and 1.2 mbined nd to MPL-21 (Ju 23.2008 Version MPI-3.0( r21 2012 1 of MPI-2.2.Ve MPI-31 (I was an exten 0015 5 PI-4.0 (June 9, doqpe3nsioms 2021)adds significant new features t 18 Comments.Please send comments on MPI to the MPI Forum as follows: 1.Subscribe to https://lists.mpi-forum.org/mailman/listinfo/mpi-comments t-fortogeher wth the veron Onlyuetheotfdalvesio e page and line numbers on w ch you are commenting 34 Your comment will be forwarded to mpl forum committee members for consideration Messages sent from an unsubscribed e-mail address will not be considered. ©1993,1994,1995,1996,1997,2008,2009,2012,2015,2021 University of Tennessee. 46 Knoxville,Tennessee.Permission to copy without fee all or part of this material is granted, provided the University of Tennessee copyright notice and the title of this document appear, and notice is given that copying is by permission of the University of Tennessee.This document describes the Message-Passing Interface (MPI) standard, version 4.0. The MPI standard includes point-to-point message-passing, collective communications, group and communicator concepts, process topologies, environmental management, process cre￾ation and management, one-sided communications, extended collective operations, external interfaces, I/O, some miscellaneous topics, and multiple tool interfaces. Language bindings for C and Fortran are defined. Historically, the evolution of the standard is from MPI-1.0 (May 5, 1994) to MPI-1.1 (June 12, 1995) to MPI-1.2 (July 18, 1997), with several clarifications and additions and published as part of the MPI-2 document, to MPI-2.0 (July 18, 1997), with new functional￾ity, to MPI-1.3 (May 30, 2008), combining for historical reasons the documents 1.1 and 1.2 and some errata documents to one combined document, and to MPI-2.1 (June 23, 2008), combining the previous documents. Version MPI-2.2 (September 4, 2009) added additional clarifications and seven new routines. Version MPI-3.0 (September 21, 2012) was an exten￾sion of MPI-2.2. Version MPI-3.1 (June 4, 2015) added clarifications and minor extensions to MPI-3.0. Version MPI-4.0 (June 9, 2021) adds significant new features to MPI-3.1. Comments. Please send comments on MPI to the MPI Forum as follows: 1. Subscribe to https://lists.mpi-forum.org/mailman/listinfo/mpi-comments 2. Send your comment to: mpi-comments@lists.mpi-forum.org, together with the version of the MPI standard and the page and line numbers on which you are commenting. Only use the official versions. Your comment will be forwarded to MPI Forum committee members for consideration. Messages sent from an unsubscribed e-mail address will not be considered. ©1993, 1994, 1995, 1996, 1997, 2008, 2009, 2012, 2015, 2021 University of Tennessee, Knoxville, Tennessee. Permission to copy without fee all or part of this material is granted, provided the University of Tennessee copyright notice and the title of this document appear, and notice is given that copying is by permission of the University of Tennessee. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 ii