PROGRAM f07gsfe ! F07GSF Example Program Text ! Mark 23 Release. NAG Copyright 2011. ! .. Use Statements .. USE nag_library, ONLY : nag_wp, x04dbf, zpptrf, zpptrs ! .. Implicit None Statement .. IMPLICIT NONE ! .. Parameters .. INTEGER, PARAMETER :: nin = 5, nout = 6 ! .. Local Scalars .. INTEGER :: i, ifail, info, j, ldb, n, nrhs CHARACTER (1) :: uplo ! .. Local Arrays .. COMPLEX (KIND=nag_wp), ALLOCATABLE :: ap(:), b(:,:) CHARACTER (1) :: clabs(1), rlabs(1) ! .. Executable Statements .. WRITE (nout,*) 'F07GSF Example Program Results' ! Skip heading in data file READ (nin,*) READ (nin,*) n, nrhs ldb = n ALLOCATE (ap(n*(n+1)/2),b(ldb,nrhs)) ! Read A and B from data file READ (nin,*) uplo IF (uplo=='U') THEN READ (nin,*) ((ap(i+j*(j-1)/2),j=i,n),i=1,n) ELSE IF (uplo=='L') THEN READ (nin,*) ((ap(i+(2*n-j)*(j-1)/2),j=1,i),i=1,n) END IF READ (nin,*) (b(i,1:nrhs),i=1,n) ! Factorize A ! The NAG name equivalent of zpptrf is f07grf CALL zpptrf(uplo,n,ap,info) WRITE (nout,*) FLUSH (nout) IF (info==0) THEN ! Compute solution ! The NAG name equivalent of zpptrs is f07gsf CALL zpptrs(uplo,n,nrhs,ap,b,ldb,info) ! Print solution ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 CALL x04dbf('General',' ',n,nrhs,b,ldb,'Bracketed','F7.4', & 'Solution(s)','Integer',rlabs,'Integer',clabs,80,0,ifail) ELSE WRITE (nout,*) 'A is not positive definite' END IF END PROGRAM f07gsfe