SLATEC Routines --- LA05AD ---

*DECK LA05AD
      SUBROUTINE LA05AD (A, IND, NZ, IA, N, IP, IW, W, G, U)
C***BEGIN PROLOGUE  LA05AD
C***SUBSIDIARY
C***PURPOSE  Subsidiary to DSPLP
C***LIBRARY   SLATEC
C***TYPE      DOUBLE PRECISION (LA05AS-S, LA05AD-D)
C***AUTHOR  (UNKNOWN)
C***DESCRIPTION
C
C     THIS SUBPROGRAM IS A SLIGHT MODIFICATION OF A SUBPROGRAM
C     FROM THE C. 1979 AERE HARWELL LIBRARY.  THE NAME OF THE
C     CORRESPONDING HARWELL CODE CAN BE OBTAINED BY DELETING
C     THE FINAL LETTER =D= IN THE NAMES USED HERE.
C     REVISIONS MADE BY R J HANSON, SNLA, AUGUST, 1979.
C     REVISED SEP. 13, 1979.
C
C     ROYALTIES HAVE BEEN PAID TO AERE-UK FOR USE OF THEIR CODES
C     IN THE PACKAGE GIVEN HERE.  ANY PRIMARY USAGE OF THE HARWELL
C     SUBROUTINES REQUIRES A ROYALTY AGREEMENT AND PAYMENT BETWEEN
C     THE USER AND AERE-UK.  ANY USAGE OF THE SANDIA WRITTEN CODES
C     DSPLP( ) (WHICH USES THE HARWELL SUBROUTINES) IS PERMITTED.
C
C IP(I,1),IP(I,2) POINT TO THE START OF ROW/COL I.
C IW(I,1),IW(I,2) HOLD THE NUMBER OF NON-ZEROS IN ROW/COL I.
C DURING THE MAIN BODY OF THIS SUBROUTINE THE VECTORS IW(.,3),IW(.,5),
C     IW(.,7) ARE USED TO HOLD DOUBLY LINKED LISTS OF ROWS THAT HAVE
C     NOT BEEN PIVOTAL AND HAVE EQUAL NUMBERS OF NON-ZEROS.
C IW(.,4),IW(.,6),IW(.,8) HOLD SIMILAR LISTS FOR THE COLUMNS.
C IW(I,3),IW(I,4) HOLD FIRST ROW/COLUMN TO HAVE I NON-ZEROS
C     OR ZERO IF THERE ARE NONE.
C IW(I,5), IW(I,6) HOLD ROW/COL NUMBER OF ROW/COL PRIOR TO ROW/COL I
C     IN ITS LIST, OR ZERO IF NONE.
C IW(I,7), IW(I,8) HOLD ROW/COL NUMBER OF ROW/COL AFTER ROW/COL I
C     IN ITS LIST, OR ZERO IF NONE.
C FOR ROWS/COLS THAT HAVE BEEN PIVOTAL IW(I,5),IW(I,6) HOLD NEGATION OF
C     POSITION OF ROW/COL I IN THE PIVOTAL ORDERING.
C
C***SEE ALSO  DSPLP
C***ROUTINES CALLED  D1MACH, LA05ED, MC20AD, XERMSG, XSETUN
C***COMMON BLOCKS    LA05DD
C***REVISION HISTORY  (YYMMDD)
C   811215  DATE WRITTEN
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   890605  Added D1MACH to list of DOUBLE PRECISION variables.
C   890605  Corrected references to XERRWV.  (WRB)
C           (WRB)
C   890831  Modified array declarations.  (WRB)
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900315  CALLs to XERROR changed to CALLs to XERMSG.  (THJ)
C   900402  Added TYPE section.  (WRB)
C   900510  Convert XERRWV calls to XERMSG calls.  (RWC)
C***END PROLOGUE  LA05AD