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 6.5.22. 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