Chap 4 - Collectives de déplacement de données

calculquebec · May 10, 2024 · 3359b7f · 3359b7f
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commit 3359b7f
Showing 1 changed file with 101 additions and 3 deletions.
diff --git a/4-collectives.ipynb b/4-collectives.ipynb
@@ -129,7 +129,7 @@
   },
   {
    "cell_type": "markdown",
-   "id": "0f26d881-eb90-4ff6-b202-3e3f4ec0417e",
+   "id": "88e3f8b9-6001-4453-a866-59ef3fb7545f",
    "metadata": {},
    "source": [
     "[En **C**](https://www.mpi-forum.org/docs/mpi-4.1/mpi41-report.pdf#section.6.5) :\n",
@@ -143,8 +143,14 @@
     "ierr = MPI_Gather(&a, 1, MPI_INT,\n",
     "                   b, 1, MPI_INT, 2, MPI_COMM_WORLD);\n",
     "\n",
-    "```\n",
-    "\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "c7a6cd00-0ec9-4afa-9e6f-ed43ff50ef3b",
+   "metadata": {},
+   "source": [
     "[En **Python**](https://mpi4py.readthedocs.io/en/latest/reference/mpi4py.MPI.Comm.html#mpi4py.MPI.Comm.gather) :\n",
     "\n",
     "```Python\n",
@@ -154,6 +160,98 @@
     "```"
    ]
   },
+  {
+   "cell_type": "markdown",
+   "id": "321dd480-724b-4261-9c87-efd2591f7439",
+   "metadata": {},
+   "source": [
+    "### Regroupement à tous avec `MPI_Allgather`\n",
+    "\n",
+    "C'est l'équivalent de `MPI_Gather` + `MPI_Bcast`,\n",
+    "mais en plus efficace :\n",
+    "\n",
+    "![Figure MPI_Allgather](images/mpi_allgather.svg)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "d50e117b-3d33-40e2-a1f8-ba8825471c05",
+   "metadata": {},
+   "source": [
+    "[En **C**](https://www.mpi-forum.org/docs/mpi-4.1/mpi41-report.pdf#section.6.7) :\n",
+    "\n",
+    "```C\n",
+    "// int MPI_Allgather(\n",
+    "//     void *envoi, int compte_envoi, MPI_Datatype type_envoi,\n",
+    "//     void *recep, int compte_recep, MPI_Datatype type_recep,\n",
+    "//     MPI_Comm comm)\n",
+    "\n",
+    "ierr = MPI_Allgather(&a, 1, MPI_INT,\n",
+    "                      b, 1, MPI_INT, MPI_COMM_WORLD);\n",
+    "\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "07b7b72a-17d2-413d-b8a1-fa5bee599e02",
+   "metadata": {},
+   "source": [
+    "[En **Python**](https://mpi4py.readthedocs.io/en/latest/reference/mpi4py.MPI.Comm.html#mpi4py.MPI.Comm.allgather) :\n",
+    "\n",
+    "```Python\n",
+    "# allgather(envoi: Any) -> list[Any]\n",
+    "\n",
+    "b = comm.allgather(a)\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "5724389a-680a-44ca-8776-a1b3b01ab7e2",
+   "metadata": {},
+   "source": [
+    "### Transposition globale avec `MPI_Alltoall`\n",
+    "\n",
+    "C'est l'équivalent de `MPI_Scatter` * `MPI_Gather`,\n",
+    "mais en plus efficace :\n",
+    "\n",
+    "![Figure MPI_Alltoall](images/mpi_alltoall.svg)"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "f2e6f727-8b46-4a04-92e5-738b609989a0",
+   "metadata": {},
+   "source": [
+    "[En **C**](https://www.mpi-forum.org/docs/mpi-4.1/mpi41-report.pdf#section.6.8) :\n",
+    "\n",
+    "```C\n",
+    "// int MPI_Alltoall(\n",
+    "//     void *envoi, int compte_envoi, MPI_Datatype type_envoi,\n",
+    "//     void *recep, int compte_recep, MPI_Datatype type_recep,\n",
+    "//     MPI_Comm comm)\n",
+    "\n",
+    "ierr = MPI_Alltoall(&a, 1, MPI_INT,\n",
+    "                     b, 1, MPI_INT, MPI_COMM_WORLD);\n",
+    "\n",
+    "```"
+   ]
+  },
+  {
+   "cell_type": "markdown",
+   "id": "98bf10fa-85de-4aad-baa8-5034e55e87e4",
+   "metadata": {},
+   "source": [
+    "[En **Python**](https://mpi4py.readthedocs.io/en/latest/reference/mpi4py.MPI.Comm.html#mpi4py.MPI.Comm.alltoall) :\n",
+    "\n",
+    "```Python\n",
+    "# alltoall(envoi: Sequence[Any]) -> list[Any]\n",
+    "\n",
+    "b = comm.alltoall(a)\n",
+    "```"
+   ]
+  },
   {
    "cell_type": "code",
    "execution_count": null,