" np.copyto(snd_buf, rcv_buf) # # We make a copy here. What happens if we write snd_buf = rcv_buf instead?\n",
" # Remember that snd_buf = rcv_buf binds them to the same object (i.e. snd_buf and rcv_buf are then two different names pointing to the same object), which is unintended and can lead to incorrect code.\n",
" np.copyto(snd_buf, rcv_buf) # # We make a copy here. What happens if we write snd_buf = rcv_buf instead?\n",
" # Remember that snd_buf = rcv_buf binds them to the same object (i.e. snd_buf and rcv_buf are then two different names pointing to the same object), which is unintended and can lead to incorrect code.\n",
" np.copyto(snd_buf, rcv_buf) # # We make a copy here. What happens if we write snd_buf = rcv_buf instead?\n",
" # Remember that snd_buf = rcv_buf binds them to the same object (i.e. snd_buf and rcv_buf are then two different names pointing to the same object), which is unintended and can lead to incorrect code.\n",
<summarymarkdown="span"><b>Author, acknowledgment, copyright, and license for this notebook</b></summary>
-<b>Author:</b> Claudia Blaas-Schenner (VSC Research Center, TU Wien), 18 November 2024
-<b>Based on</b> the [MPI course developed by Rolf Rabenseifner, HLRS](https://www.hlrs.de/training/self-study-materials/mpi-course-material) that is under a quite restrictive copyright by Rolf Rabenseifner and HLRS. The copyrighted material (some images, some exercise descriptions, some code snippets) is used with permission. Some parts taken from the HLRS material are modified and the Jupyter Notebook is extended with own material of the Notebook authors.
-**nonblocking send procedure** (other send modes have the same syntax)
- source rank sends the message defined by (buf, count, datatype) to the dest(ination) rank
<br> <br>
- IN buf initial address of send buffer (choice)
- IN count number of elements in send buffer (non-negative
integer)
- IN datatype datatype of each send buffer element (handle)
- IN dest rank of destination (integer)
- IN tag message tag (integer)
- IN comm communicator (handle)
- OUT request communication request (handle)
<br> <br>
- C binding
<br> int **MPI_Isend**(const void ***buf**, int **count**, MPI_Datatype **datatype**, int **dest**, int **tag**, MPI_Comm **comm**, MPI_Request ***request**)
- dest(ination) rank receives a message from the source rank and stores it at (buf, count, datatype)
<br> <br>
- OUT buf initial address of receive buffer (choice)
- IN count number of elements in receive buffer (non-negative
integer)
- IN datatype datatype of each receive buffer element (handle)
- IN source rank of source or MPI_ANY_SOURCE (integer)
- IN tag message tag or MPI_ANY_TAG (integer)
- IN comm communicator (handle)
- OUT request communication request (handle)
<br> <br>
- C binding
<br> int **MPI_Irecv**(void ***buf**, int **count**, MPI_Datatype **datatype**, int **source**, int **tag**, MPI_Comm **comm**, MPI_Request ***request**)
- The functions MPI_WAIT and MPI_TEST are used to complete a nonblocking communication.
- The completion of a send operation indicates that the sender is now free to update
the send buffer (the send operation itself leaves the content of the send buffer unchanged).
It does not indicate that the message has been received, rather, it may have been buffered
by the communication subsystem. However, if a synchronous mode send was used, the
completion of the send operation indicates that a matching receive was initiated, and that
the message will eventually be received by this matching receive.
- The completion of a receive operation indicates that the receive buffer contains the
received message, the receiver is now free to access it, and that the status object is set. It does not indicate that the matching send operation has completed (but indicates, of course,
- IN count list length (non-negative integer)
- INOUT array_of_requests array of requests (array of handles)
- OUT array_of_statuses array of status objects (array of status)
<br> <br>
- C binding
<br> int **MPI_Waitall**(int **count**, MPI_Request **array_of_requests[]**,
np.copyto(snd_buf,rcv_buf)# # We make a copy here. What happens if we write snd_buf = rcv_buf instead?
# Remember that snd_buf = rcv_buf binds them to the same object (i.e. snd_buf and rcv_buf are then two different names pointing to the same object), which is unintended and can lead to incorrect code.
np.copyto(snd_buf,rcv_buf)# # We make a copy here. What happens if we write snd_buf = rcv_buf instead?
# Remember that snd_buf = rcv_buf binds them to the same object (i.e. snd_buf and rcv_buf are then two different names pointing to the same object), which is unintended and can lead to incorrect code.
np.copyto(snd_buf,rcv_buf)# # We make a copy here. What happens if we write snd_buf = rcv_buf instead?
# Remember that snd_buf = rcv_buf binds them to the same object (i.e. snd_buf and rcv_buf are then two different names pointing to the same object), which is unintended and can lead to incorrect code.
<summarymarkdown="span"><b>Author, acknowledgment, copyright, and license for this notebook</b></summary>
-<b>Author:</b> Claudia Blaas-Schenner (VSC Research Center, TU Wien), 18 November 2024
-<b>Based on</b> the [MPI course developed by Rolf Rabenseifner, HLRS](https://www.hlrs.de/training/self-study-materials/mpi-course-material) that is under a quite restrictive copyright by Rolf Rabenseifner and HLRS. The copyrighted material (some images, some exercise descriptions, some code snippets) is used with permission. Some parts taken from the HLRS material are modified and the Jupyter Notebook is extended with own material of the Notebook authors.