* F07PEF Example Program Text * Mark 15 Release. NAG Copyright 1991. * .. Parameters .. INTEGER NIN, NOUT PARAMETER (NIN=5,NOUT=6) INTEGER NMAX, NRHMAX, LDB PARAMETER (NMAX=8,NRHMAX=NMAX,LDB=NMAX) * .. Local Scalars .. INTEGER I, IFAIL, INFO, J, N, NRHS CHARACTER UPLO * .. Local Arrays .. DOUBLE PRECISION AP(NMAX*(NMAX+1)/2), B(LDB,NRHMAX) INTEGER IPIV(NMAX) * .. External Subroutines .. EXTERNAL DSPTRF, DSPTRS, X04CAF * .. Executable Statements .. WRITE (NOUT,*) 'F07PEF Example Program Results' * Skip heading in data file READ (NIN,*) READ (NIN,*) N, NRHS IF (N.LE.NMAX .AND. NRHS.LE.NRHMAX) THEN * * Read A and B from data file * READ (NIN,*) UPLO IF (UPLO.EQ.'U') THEN READ (NIN,*) ((AP(I+J*(J-1)/2),J=I,N),I=1,N) ELSE IF (UPLO.EQ.'L') THEN READ (NIN,*) ((AP(I+(2*N-J)*(J-1)/2),J=1,I),I=1,N) END IF READ (NIN,*) ((B(I,J),J=1,NRHS),I=1,N) * * Factorize A * CALL DSPTRF(UPLO,N,AP,IPIV,INFO) * WRITE (NOUT,*) IF (INFO.EQ.0) THEN * * Compute solution * CALL DSPTRS(UPLO,N,NRHS,AP,IPIV,B,LDB,INFO) * * Print solution * IFAIL = 0 * CALL X04CAF('General',' ',N,NRHS,B,LDB,'Solution(s)',IFAIL) * ELSE WRITE (NOUT,*) 'The factor D is singular' END IF END IF * END