DPBSL(3F)

DPBSL - DPBSL solves the double precision symmetric positive definite band system A*X = B using the factors computed by DPBCO or DPBFA.

As shipped in IRIX 6.5.22. Unchanged since IRIX 6.5.

NAME
     DPBSL   - DPBSL solves the double precision symmetric positive definite
     band system  A*X = B using the factors computed by DPBCO or DPBFA.


SYNOPSYS
      SUBROUTINE DPBSL(ABD,LDA,N,M,B)

DESCRIPTION
     On Entry

     ABD DOUBLE PRECISION(LDA, N)
        the output from DPBCO or DPBFA.

     LDA INTEGER
        the leading dimension of the array  ABD .

     N INTEGER
        the order of the matrix  A .

     M INTEGER
        the number of diagonals above the main diagonal.

     B DOUBLE PRECISION(N)
        the right hand side vector.  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 usually
     caused by improper subroutine arguments.  It will not occur if the
     subroutines are called correctly, and  INFO .EQ. 0 .  To compute
     INVERSE(A) * C  where  C  is a matrix with  P  columns
        CALL DPBCO(ABD,LDA,N,RCOND,Z,INFO)
        IF (RCOND is too small .OR. INFO .NE. 0) GO TO ...
        DO 10 J = 1, P
        CALL DPBSL(ABD,LDA,N,C(1,J)) 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