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MPI_Type_lb(3OpenMPI)                                                                  MPI_Type_lb(3OpenMPI)



NAME
       MPI_Type_lb  - Returns the lower bound of a data type. This may differ from zero if the type was con-structed constructed
       structed using MPI_LB. Use of this routine is deprecated.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Type_lb(MPI_Datatype datatype, MPI_Aint *displacement)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_TYPE_LB(DATATYPE, DISPLACEMENT, IERROR)
            INTEGER   DATATYPE, DISPLACEMENT, IERROR



INPUT PARAMETER
       datatype  Datatype (handle).


OUTPUT PARAMETERS
       displacement
                 Displacement of lower bound from origin, in bytes (integer).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       Note that use of this routine is deprecated as of MPI-2. Please use MPI_Type_get_extent instead.

       This deprecated routine is not available in C++.

       MPI_Type_lb returns the lower bound of a data type.

       The "pseudo-datatypes," MPI_LB and MPI_UB, can be used, respectively, to mark the lower bound (or the
       upper bound) of a datatype. These pseudo-datatypes occupy no space (extent (MPI_LB) = extent (MPI_UB)
       =0. They do not affect the size or count of a datatype, and do not affect the context  of  a  message
       created  with  this datatype. However, they do affect the definition of the extent of a datatype and,
       therefore, affect the outcome of a replication of this datatype by a datatype constructor.

       In general, if

           Typemap = {(type0, disp0), ..., (type(n-1), disp(n-1)}

       then the lower bound of Typemap is defined to be

                         (min(j) disp(j)                          if no entry has
           lb(Typemap) = (                                        basic type lb
                         (min(j) {disp(j) such that type(j) = lb} otherwise

       Similarly, the upper bound of Typemap is defined to be

                         (max(j) disp(j) + sizeof((type(j)) + e   if no entry has
           ub(Typemap) = (                                        basic type ub
                         (max(j) {disp(j) such that type(j) = ub} otherwise

       Then

           extent(Typemap) = ub(Typemap) - lb(Typemap)

       If type(i) requires alignment to a byte address that is a multiple of k(i), then e is the least  non-negative nonnegative
       negative increment needed to round extent(Typemap) to the next multiple of max(i) k(i).


ERRORS
       Almost  all  MPI  routines return an error value; C routines as the value of the function and Fortran
       routines in the last argument. C++ functions do not return errors. If the default  error  handler  is
       set  to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism will be used to throw
       an MPI:Exception object.

       Before the error value is returned, the current MPI error handler is called. By default,  this  error
       handler  aborts  the  MPI  job, except for I/O function errors. The error handler may be changed with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used  to  cause  error
       values  to  be  returned.  Note  that MPI does not guarantee that an MPI program can continue past an
       error.


SEE ALSO
       MPI_Type_get_extent




Open MPI 1.2                                   September 2006                          MPI_Type_lb(3OpenMPI)