Option Arguments

 

Arguments  specifying options are usually of type CHARACTER1. The arguments that specify options are character arguments with the names SIDE, TRANS, UPLO, and DIAG. On entry to a ScaLAPACK routine, these arguments are global input and must have the same value on each process in the process grid.

SIDE  is used by the routines as follows:

TRANS  is used by the routines as follows:

In the real case the values `T' and `C' have the same meaning, and in the complex case the value `T' is not allowed.

UPLO  is used by the Hermitian, symmetric, and triangular distributed matrix routines to specify whether the upper or lower triangle is being referenced as follows:

DIAG  is used by the triangular distributed matrix routines to specify whether the distributed matrix is unit triangular, as follows:

When DIAG is supplied as `U', the diagonal elements are not referenced. For example:

UPLO
(global input) CHARACTER1
= 'U': Upper triangle of the matrix A(IA:IA+M-1,JA:JA+N-1);
= 'L': Lower triangle of the matrix A(IA:IA+M-1,JA:JA+N-1).

The corresponding lower-case characters may be supplied (with the same meaning), but any other value is illegal (see section 4.6.6).

A longer character string can be passed as the actual argument, making the calling program more readable, but only the first character is significant; this is a standard feature of Fortran 77. For example:

       CALL PSPOTRS('upper', . . . )