Program f07aafe ! F07AAF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: dgesv, nag_wp, x04caf ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Integer, Parameter :: nin = 5, nout = 6 ! .. Local Scalars .. Integer :: i, ifail, info, lda, ldb, n ! .. Local Arrays .. Real (Kind=nag_wp), Allocatable :: a(:,:), b(:) Integer, Allocatable :: ipiv(:) ! .. Executable Statements .. Write (nout,*) 'F07AAF Example Program Results' Write (nout,*) ! Skip heading in data file Read (nin,*) Read (nin,*) n lda = n ldb = n Allocate (a(lda,n),b(ldb),ipiv(n)) ! Read A and B from data file Read (nin,*)(a(i,1:n),i=1,n) Read (nin,*) b(1:n) ! Solve the equations Ax = b for x ! The NAG name equivalent of dgesv is f07aaf Call dgesv(n,1,a,lda,ipiv,b,ldb,info) If (info==0) Then ! Print solution Write (nout,*) 'Solution' Write (nout,99999) b(1:n) ! Print details of factorization Write (nout,*) Flush (nout) ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04caf('General',' ',n,n,a,lda,'Details of factorization',ifail) ! 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 f07aafe