DGBSL(3F)

NAME
     DGBSL   - DGBSL solves the double precision band system A * X = B  or
     TRANS(A) * X = B using the factors computed by DGBCO or DGBFA.


SYNOPSYS
      SUBROUTINE DGBSL(ABD,LDA,N,ML,MU,IPVT,B,JOB)

DESCRIPTION
     On Entry

     ABD DOUBLE PRECISION(LDA, N)
        the output from DGBCO or DGBFA.

     LDA INTEGER
        the leading dimension of the array  ABD .

     N INTEGER
        the order of the original matrix.

     ML INTEGER
        number of diagonals below the main diagonal.

     MU INTEGER
        number of diagonals above the main diagonal.

     IPVT INTEGER(N)
        the pivot vector from DGBCO or DGBFA.

     B DOUBLE PRECISION(N)
        the right hand side vector.

     JOB INTEGER
        = 0         to solve  A*X = B ,
        = nonzero   to solve  TRANS(A)*X = B , where
        TRANS(A)  is the transpose.  On Return

     B the solution vector  X . Error Condition

     A division by zero will occur if the input factor contains a zero on the
     diagonal.  Technically this indicates singularity but it is often caused
     by improper arguments or improper setting of LDA .  It will not occur if
     the subroutines are called correctly and if DGBCO has set RCOND .GT. 0.0
     or DGBFA has set INFO .EQ. 0 .  To compute  INVERSE(A) * C  where  C  is
     a matrix with  P  columns
        CALL DGBCO(ABD,LDA,N,ML,MU,IPVT,RCOND,Z)
        IF (RCOND is too small) GO TO ...
        DO 10 J = 1, P
        CALL DGBSL(ABD,LDA,N,ML,MU,IPVT,C(1,J),0) 10 CONTINUE LINPACK.  This
     version dated 08/14/78 .  Cleve Moler, University of New Mexico, Argonne
     National Lab.  Subroutines and Functions BLAS DAXPY,DDOT Fortran MIN0