*DECK DRMGEN
SUBROUTINE DRMGEN (NELTMX, FACTOR, IERR, N, NELT, ISYM, IA, JA, A,
$ F, SOLN, DSUM, ITMP, IDIAG)
C***BEGIN PROLOGUE DRMGEN
C***SUBSIDIARY
C***PURPOSE This routine generates a "Random" symmetric or
C non-symmetric matrix of size N for use in the SLAP
C Quick Checks.
C***LIBRARY SLATEC (SLAP)
C***TYPE DOUBLE PRECISION (SRMGEN-S, DRMGEN-D)
C***AUTHOR Seager, Mark K., (LLNL)
C seager@llnl.gov
C Lawrence Livermore National Laboratory
C PO BOX 808, L-300
C Livermore, CA 94550
C (510) 423-3141
C***DESCRIPTION
C
C *Usage:
C INTEGER NELTMX, IERR, N, NELT, ISYM,
C INTEGER IA(NELTMX), JA(NELTMX), ITMP(N), IDIAG(N)
C DOUBLE PRECISION FACTOR, A(NELTMX), F(N), SOLN(N), DSUM(N)
C
C CALL DRMGEN( NELTMX, FACTOR, IERR, N, NELT, ISYM,
C $ IA, JA, A, F, SOLN, DSUM, ITMP, IDIAG )
C
C *Arguments:
C
C NELTMX :IN Integer.
C Maximum number of non-zeros that can be created by this
C routine for storage in the IA, JA, A arrays, see below.
C FACTOR :IN Double Precision.
C Non-zeros in the upper triangle are set to FACTOR times
C the corresponding entry in the lower triangle when a non-
C symmetric matrix is requested (See ISYM, below).
C IERR :OUT Integer.
C Return error flag.
C IERR = 0 => everything went OK.
C = 1 => Ran out of space trying to create matrix.
C Set NELTMX to something larger and retry.
C N :IN Integer.
C Size of the linear system to generate (number of unknowns).
C NELT :OUT Integer.
C Number of non-zeros stored in the IA, JA, A arrays, see below.
C ISYM :IN Integer.
C Flag to indicate the type of matrix to generate:
C ISYM = 0 => Non-Symmetric Matrix (See FACTOR, above).
C = 1 => Symmetric Matrix.
C IA :OUT Integer IA(NELTMX).
C Stores the row indices for the non-zeros.
C JA :OUT Integer JA(NELTMX).
C Stores the column indices for the non-zeros.
C A :OUT Double Precision A(NELTMX).
C Stores the values of the non-zeros.
C F :OUT Double Precision F(N).
C The right hand side of the linear system. Obtained by
C multiplying the matrix times SOLN, see below.
C SOLN :OUT Double Precision SOLN(N).
C The true solution to the linear system. Each component is
C chosen at random (0.0