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:
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', . . . )