HP MLIB User's Guide Vol. 2 7th Ed.

Chapter 10 Introduction to ScaLAPACK 715
ScaLAPACK arguments
B(IB:IB+N-1, JB:JB+NRHS-1). NRHS is greater than
or equal to zero.
A (Local input/Local output) REAL - Pointer into the local
memory to an array of local dimension (LLD_A,
LOC(JA+N-1)).
IA (Global input) INTEGER - The row index in the global
array A indicating the first row of A(IA:IA+M-1,
JA:JA+N-1).
JA (Global input) INTEGER - The column index in the
global array A indicating the first column of
A(IA:IA+M-1, JA:JA+N-1).
DESCA (Global and Local input) INTEGER - Array of
dimension DLEN_. The array descriptor for the global
matrix A.
B (Local input/Local output) REAL - Pointer into the local
memory to an array of local dimension (LLD_B,
LOC(JB+NRHS-1).
IB (Global input) INTEGER - The row index in the global
array B indicating the first row of B(IB:IB+N-1,
JB:JB+NRHS-1).
JB (Global input) INTEGER - The column index in the
global array B indicating the first column of
B(IB:IB+N-1, JB:JB+NRHS-1).
DESCB (Global and Local input) INTEGER - Array of
dimension DLEN_. The array descriptor for the global
matrix B.
Work arrays
Many ScaLAPACK routines require one or more work arrays to be passed as
arguments. The name of a work array is usually WORK. Sometimes IWORK or
RWORK is used to distinguish work arrays of type INTEGER or REAL.
Immediately following the work array in the argument list is the specified
length of the work array; LWORK, LIWORK, or LRWORK, respectively. LWORK
is defined as the minimum amount of workspace necessary to perform the
operation specified.
The first element of the work array is always used to return the correct value of
LWORK for the computation. Whether or not an error is detected, the minimum
value of LWORK is placed in WORK(1) on exit from the routine.
If the user passes a value for LWORK that is too small, an input error is
detected and INFO is set accordingly. The correct value for LWORK is placed in