SLATEC Routines --- DGESL ---

*DECK DGESL
      SUBROUTINE DGESL (A, LDA, N, IPVT, B, JOB)
C***BEGIN PROLOGUE  DGESL
C***PURPOSE  Solve the real system A*X=B or TRANS(A)*X=B using the
C            factors computed by DGECO or DGEFA.
C***LIBRARY   SLATEC (LINPACK)
C***CATEGORY  D2A1
C***TYPE      DOUBLE PRECISION (SGESL-S, DGESL-D, CGESL-C)
C***KEYWORDS  LINEAR ALGEBRA, LINPACK, MATRIX, SOLVE
C***AUTHOR  Moler, C. B., (U. of New Mexico)
C***DESCRIPTION
C
C     DGESL solves the double precision system
C     A * X = B  or  TRANS(A) * X = B
C     using the factors computed by DGECO or DGEFA.
C
C     On Entry
C
C        A       DOUBLE PRECISION(LDA, N)
C                the output from DGECO or DGEFA.
C
C        LDA     INTEGER
C                the leading dimension of the array  A .
C
C        N       INTEGER
C                the order of the matrix  A .
C
C        IPVT    INTEGER(N)
C                the pivot vector from DGECO or DGEFA.
C
C        B       DOUBLE PRECISION(N)
C                the right hand side vector.
C
C        JOB     INTEGER
C                = 0         to solve  A*X = B ,
C                = nonzero   to solve  TRANS(A)*X = B  where
C                            TRANS(A)  is the transpose.
C
C     On Return
C
C        B       the solution vector  X .
C
C     Error Condition
C
C        A division by zero will occur if the input factor contains a
C        zero on the diagonal.  Technically this indicates singularity
C        but it is often caused by improper arguments or improper
C        setting of LDA .  It will not occur if the subroutines are
C        called correctly and if DGECO has set RCOND .GT. 0.0
C        or DGEFA has set INFO .EQ. 0 .
C
C     To compute  INVERSE(A) * C  where  C  is a matrix
C     with  P  columns
C           CALL DGECO(A,LDA,N,IPVT,RCOND,Z)
C           IF (RCOND is too small) GO TO ...
C           DO 10 J = 1, P
C              CALL DGESL(A,LDA,N,IPVT,C(1,J),0)
C        10 CONTINUE
C
C***REFERENCES  J. J. Dongarra, J. R. Bunch, C. B. Moler, and G. W.
C                 Stewart, LINPACK Users' Guide, SIAM, 1979.
C***ROUTINES CALLED  DAXPY, DDOT
C***REVISION HISTORY  (YYMMDD)
C   780814  DATE WRITTEN
C   890831  Modified array declarations.  (WRB)
C   890831  REVISION DATE from Version 3.2
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900326  Removed duplicate information from DESCRIPTION section.
C           (WRB)
C   920501  Reformatted the REFERENCES section.  (WRB)
C***END PROLOGUE  DGESL