Basetypes

A basetype is a type which is used to define other types (such as structs or vectors). A basetype can be given in two ways:

• as a string, denoting a predefined MPI datatype. Currently MPI_CHAR, MPI_BYTE, MPI_INT, MPI_LONG, MPI_DOUBLE, and MPI_LONG_DOUBLE are allowed.
• or as a comma-separated list of tuples (see below.)

Each tuple describes an element of the basetype. The first entry of a tuple gives the length of the element in bytes. The second element gives the displacement of this element in bytes. I.e., the address where the element starts relative to the beginning of the basetype. For example: (4,0) denotes something like MPI_DOUBLE (on most machines); simply four bytes at the beginning of the datatype. A basetype of two MPI_CHAR's is decribed by (1,0),(1,1). Currently 10 basetypes can be defined in SKaMPI  by the user.