DPPSL(3F)

DPPSL - DPPSL solves the double precision symmetric positive definite system A * X = B using the factors computed by DPPCO or DPPFA.

Showing IRIX 6.5.30 (default release). Unchanged since IRIX 6.5.

NAME
     DPPSL   - DPPSL solves the double precision symmetric positive definite
     system A * X = B using the factors computed by DPPCO or DPPFA.


SYNOPSYS
      SUBROUTINE DPPSL(AP,N,B)

DESCRIPTION
     On Entry

     AP DOUBLE PRECISION (N*(N+1)/2)
        the output from DPPCO or DPPFA.

     N INTEGER
        the order of the matrix  A .

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