Vector datatypes

Vector Datatype Constructor

• This constructor replicates a datatype, taking blocks at fixed offsets.

   mpi_type_vector (count, blocklen,stride,
                    oldtype, newtype, ierr)

• The new datatype consists of:
  • count blocks,
  • each block is a repetition of blocklen items of oldtype,
  • the start of successive blocks is offset by stride items of oldtype.
• If count=2, stride=4, blocklen=3, then newtype is:

    {(double,  0), (char,   8), 
     (double, 16), (char,  24),
     (double, 32), (char,  40), 
     (double, 64), (char,  72),
     (double, 80), (char,  88), 
     (double, 96), (char, 104)}