SPPSL(3F)SPPSL(3F)NAMESPPSL - 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
Page 1