Program f07acfe ! F07ACF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dsgesv, nag_rp, nag_wp ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, info, iter, lda, ldb, ldx, n, r ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: a(:,:), b(:,:), work(:), x(:,:) Real (Kind=nag_rp), Allocatable :: swork(:) Integer, Allocatable :: ipiv(:) ! .. Executable Statements .. Write (nout,*) 'F07ACF Example Program Results' Write (nout,*) ! Skip heading in data file Read (nin,*) Read (nin,*) n, r lda = n ldb = n ldx = n Allocate (a(lda,n),b(n,r),work(n*r),x(ldx,r),swork(n*(n+r)),ipiv(n)) ! Read A and B from data file Read (nin,*)(a(i,1:n),i=1,n) Read (nin,*)(b(i,1:r),i=1,n) ! Solve the equations Ax = b for x ! The NAG name equivalent of dsgesv is f07acf Call dsgesv(n,r,a,lda,ipiv,b,ldb,x,ldx,work,swork,iter,info) If (info==0) Then ! Print solution Write (nout,*) 'Solution' Write (nout,99999)(x(i,1:r),i=1,n) ! Print pivot indices Write (nout,*) Write (nout,*) 'Pivot indices' Write (nout,99998) ipiv(1:n) Else Write (nout,99997) 'The (', info, ',', info, ')', & ' element of the factor U is zero' End If 99999 Format ((3X,7F11.4)) 99998 Format ((3X,7I11)) 99997 Format (1X,A,I3,A,I3,A,A) End Program f07acfe