DSISL(3F)
DSISL - DSISL solves the double precision symmetric system A * X = B using the factors computed by DSIFA.
As shipped in IRIX 6.5.7. Unchanged since IRIX 6.5.
NAME DSISL - DSISL solves the double precision symmetric system A * X = B using the factors computed by DSIFA. SYNOPSYS SUBROUTINE DSISL(A,LDA,N,KPVT,B) DESCRIPTION On Entry A DOUBLE PRECISION(LDA,N) the output from DSIFA. LDA INTEGER the leading dimension of the array A . N INTEGER the order of the matrix A . KPVT INTEGER(N) the pivot vector from DSIFA. B DOUBLE PRECISION(N) the right hand side vector. On Return B the solution vector X . Error Condition A division by zero may occur if DSICO has set RCOND .EQ. 0.0 or DSIFA has set INFO .NE. 0 . To compute INVERSE(A) * C where C is a matrix with P columns CALL DSIFA(A,LDA,N,KPVT,INFO) IF (INFO .NE. 0) GO TO ... DO 10 J = 1, P CALL DSISL(A,LDA,N,KPVT,C(1,J)) 10 CONTINUE LINPACK. This version dated 08/14/78 . James Bunch, Univ. Calif. San Diego, Argonne Nat. Lab. Subroutines and Functions BLAS DAXPY,DDOT Fortran IABS