SUBROUTINE DCPPLT (N, NELT, IA, JA, A, ISYM, IUNIT) C***BEGIN PROLOGUE DCPPLT C***PURPOSE Printer Plot of SLAP Column Format Matrix. C Routine to print out a SLAP Column format matrix in a C "printer plot" graphical representation. C***LIBRARY SLATEC (SLAP) C***CATEGORY N1 C***TYPE DOUBLE PRECISION (SCPPLT-S, DCPPLT-D) C***KEYWORDS DIAGNOSTICS, LINEAR SYSTEM, SLAP SPARSE C***AUTHOR Seager, Mark K., (LLNL) C Lawrence Livermore National Laboratory C PO BOX 808, L-60 C Livermore, CA 94550 (510) 423-3141 C seager@llnl.gov C***DESCRIPTION C C *Usage: C INTEGER N, NELT, IA(NELT), JA(NELT), ISYM, IUNIT C DOUBLE PRECISION A(NELT) C C CALL DCPPLT( N, NELT, IA, JA, A, ISYM, IUNIT ) C C *Arguments: C N :IN Integer C Order of the Matrix. C If N.gt.MAXORD, only the leading MAXORD x MAXORD C submatrix will be printed. (Currently MAXORD = 225.) C NELT :IN Integer. C Number of non-zeros stored in A. C IA :IN Integer IA(NELT). C JA :IN Integer JA(NELT). C A :IN Double Precision A(NELT). C These arrays should hold the matrix A in the SLAP C Column format. See "Description", below. C ISYM :IN Integer. C Flag to indicate symmetric storage format. C If ISYM=0, all non-zero entries of the matrix are stored. C If ISYM=1, the matrix is symmetric, and only the lower C triangle of the matrix is stored. C IUNIT :IN Integer. C Fortran logical I/O device unit number to write the matrix C to. This unit must be connected in a system dependent fashion C to a file or the console or you will get a nasty message C from the Fortran I/O libraries. C C *Description: C This routine prints out a SLAP Column format matrix to the C Fortran logical I/O unit number IUNIT. The numbers them C selves are not printed out, but rather a one character C representation of the numbers. Elements of the matrix that C are not represented in the (IA,JA,A) arrays are denoted by C ' ' character (a blank). Elements of A that are *ZERO* (and C hence should really not be stored) are denoted by a '0' C character. Elements of A that are *POSITIVE* are denoted by C 'D' if they are Diagonal elements and '#' if they are off C Diagonal elements. Elements of A that are *NEGATIVE* are C denoted by 'N' if they are Diagonal elements and '*' if C they are off Diagonal elements. C C =================== S L A P Column format ================== C C This routine requires that the matrix A be stored in the C SLAP Column format. In this format the non-zeros are stored C counting down columns (except for the diagonal entry, which C must appear first in each "column") and are stored in the C double precision array A. In other words, for each column C in the matrix put the diagonal entry in A. Then put in the C other non-zero elements going down the column (except the C diagonal) in order. The IA array holds the row index for C each non-zero. The JA array holds the offsets into the IA, C A arrays for the beginning of each column. That is, C IA(JA(ICOL)), A(JA(ICOL)) points to the beginning of the C ICOL-th column in IA and A. IA(JA(ICOL+1)-1), C A(JA(ICOL+1)-1) points to the end of the ICOL-th column. C Note that we always have JA(N+1) = NELT+1, where N is the C number of columns in the matrix and NELT is the number of C non-zeros in the matrix. C C Here is an example of the SLAP Column storage format for a C 5x5 Matrix (in the A and IA arrays '|' denotes the end of a C column): C C 5x5 Matrix SLAP Column format for 5x5 matrix on left. C 1 2 3 4 5 6 7 8 9 10 11 C |11 12 0 0 15| A: 11 21 51 | 22 12 | 33 53 | 44 | 55 15 35 C |21 22 0 0 0| IA: 1 2 5 | 2 1 | 3 5 | 4 | 5 1 3 C | 0 0 33 0 35| JA: 1 4 6 8 9 12 C | 0 0 0 44 0| C |51 0 53 0 55| C C *Cautions: C This routine will attempt to write to the Fortran logical output C unit IUNIT, if IUNIT .ne. 0. Thus, the user must make sure that C this logical unit is attached to a file or terminal before calling C this routine with a non-zero value for IUNIT. This routine does C not check for the validity of a non-zero IUNIT unit number. C C *Portability: C This routine, as distributed, can generate lines up to 229 C characters long. Some Fortran systems have more restricted C line lengths. Change parameter MAXORD and the large number C in FORMAT 1010 to reduce this line length. C C***REFERENCES (NONE) C***ROUTINES CALLED (NONE) C***REVISION HISTORY (YYMMDD) C 871119 DATE WRITTEN C 881213 Previous REVISION DATE C 890915 Made changes requested at July 1989 CML Meeting. (MKS) C 890922 Numerous changes to prologue to make closer to SLATEC C standard. (FNF) C 890929 Numerous changes to reduce SP/DP differences. (FNF) C 910411 Prologue converted to Version 4.0 format. (BAB) C 920511 Added complete declaration section. (WRB) C 921007 Replaced hard-wired 225 with parameter MAXORD. (FNF) C 921021 Corrected syntax of CHARACTER declaration. (FNF) C 921026 Corrected D to E in output format. (FNF) C 930701 Updated CATEGORY section. (FNF, WRB) C***END PROLOGUE DCPPLT