- Suppose that you wish to create datatypes to access the
selected (darker) elements of the two-dimensional arrays shown in the
following figures:
For figure (a), which derived datatype call would be best?
MPI_TYPE_CONTIGUOUS
MPI_TYPE_VECTOR
MPI_TYPE_INDEXED
MPI_TYPE_STRUCT
- For figure (b), which derived datatype call would be best?
MPI_TYPE_CONTIGUOUS
MPI_TYPE_VECTOR
MPI_TYPE_INDEXED
MPI_TYPE_STRUCT
- For figure (c), which derived datatype call would be best?
MPI_TYPE_CONTIGUOUS
MPI_TYPE_VECTOR
MPI_TYPE_INDEXED
MPI_TYPE_STRUCT
-
Assuming that you have already created and committed a derived datatype
to access the selected (darker) elements of the two-dimensional array
shown in figure (b):
If the array is named "buf", how should the message buffer be
specified in the send call?
Fortran: call MPI_SEND (buf(1,1), ...)
--- C: MPI_Send (buf, ...);
Fortran: call MPI_SEND (buf(2,1), ...)
--- C: MPI_Send (&buf[1][0], ...);
-
Check all that apply: if sends and receives use the datatypes listed
below, which combinations will generate an error when the program runs?
- Assume that:
- vectype1 was created with
- count_dd=10, blocklength=5, stride=10, oldtype=MPI_INT or MPI_INTEGER
- vectype2 was created with
- count_dd=10, blocklength=5, stride=20, oldtype=MPI_INT or MPI_INTEGER
- vectype3 was created with
- count_dd=10, blocklength=6, stride=10, oldtype=MPI_INT or MPI_INTEGER
receive: datatype=vectype1, count_msg=1
-
send: datatype=vectype2, count_msg=1
receive: datatype=vectype1, count_msg=1
-
send: datatype=vectype3, count_msg=1
receive: datatype=vectype3, count_msg=1
-
send: datatype=vectype1, count_msg=1
receive: datatype=vectype1, count_msg=1
-
send: datatype=MPI_INT or MPI_INTEGER, count_msg=50
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