SPBSL(3F)

SPBSL - SPBSL solves the real symmetric positive definite band system A*X = B using the factors computed by SPBCO or SPBFA.

As shipped in IRIX 6.5.5. Unchanged since IRIX 6.5.

NAME
     SPBSL   - SPBSL solves the real symmetric positive definite band system
     A*X = B using the factors computed by SPBCO or SPBFA.


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

DESCRIPTION
     On Entry

     ABD REAL(LDA, N)
        the output from SPBCO or SPBFA.

     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 REAL(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 SPBCO(ABD,LDA,N,RCOND,Z,INFO)
        IF (RCOND is too small .OR. INFO .NE. 0) GO TO ...
        DO 10 J = 1, P
        CALL SPBSL(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 SAXPY,SDOT Fortran MIN0