SPPSL(3F)

SPPSL - SPPSL solves the real symmetric positive definite system A * X = B using the factors computed by SPPCO or SPPFA.

As shipped in IRIX 6.5.19. Unchanged since IRIX 6.5.

NAME
     SPPSL   - SPPSL solves the real symmetric positive definite system A * X
     = B using the factors computed by SPPCO or SPPFA.


SYNOPSYS
      SUBROUTINE SPPSL(AP,N,B)

DESCRIPTION
     On Entry

     AP REAL (N*(N+1)/2)
        the output from SPPCO or SPPFA.

     N INTEGER
        the order of the matrix  A .

     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 SPPCO(AP,N,RCOND,Z,INFO)
        IF (RCOND is too small .OR. INFO .NE. 0) GO TO ...
        DO 10 J = 1, P
        CALL SPPSL(AP,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