DPPSL(3F)DPPSL(3F)NAMEDPPSL - 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
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