coll/base: Allgatherv MPI_IN_PLACE Bug #2805
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MPI_Allgatherv with MPI_IN_PLACE reads data from wrong location.
They were locating the MPI_IN_PLACE send buffer as
```c
send_buf = (char*)rbuf;
for (i = 0; i < rank; ++i) {
send_buf += ((ptrdiff_t)rcounts[i] * extent);
}
```
when it should be
```c
send_buf = (char*)rbuf;
send_buf += ((ptrdiff_t)disps[rank] * extent);
```
because disps[] specifies where things are in the v-style buffers.
Signed-off-by: Joshua Hursey <jhursey@us.ibm.com>
bosilca
approved these changes
Jan 24, 2017
This was referenced Feb 2, 2017
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MPI_Allgatherv with MPI_IN_PLACE reads data from wrong location.
They were locating the MPI_IN_PLACE send buffer as
when it should be
because disps[] specifies where things are in the v-style buffers.
Signed-off-by: Joshua Hursey jhursey@us.ibm.com