Program f07gtfe ! F07GTF Example Program Text ! Mark 24 Release. NAG Copyright 2012. ! .. Use Statements .. Use nag_library, Only: f06kcf, nag_wp, x02ajf, x02amf, x02bhf, x04ddf, & zdscal, zppequ ! .. Implicit None Statement .. Implicit None ! .. Parameters .. Real (Kind=nag_wp), Parameter :: one = 1.0_nag_wp Real (Kind=nag_wp), Parameter :: thresh = 0.1_nag_wp Integer, Parameter :: nin = 5, nout = 6 Character (1), Parameter :: uplo = 'U' ! .. Local Scalars .. Real (Kind=nag_wp) :: amax, big, scond, small Integer :: i, ifail, info, j, jinc, jj, n ! .. Local Arrays .. Complex (Kind=nag_wp), Allocatable :: ap(:) Real (Kind=nag_wp), Allocatable :: s(:) Character (1) :: clabs(1), rlabs(1) ! .. Intrinsic Procedures .. Intrinsic :: real ! .. Executable Statements .. Write (nout,*) 'F07GTF Example Program Results' Write (nout,*) Flush (nout) ! Skip heading in data file Read (nin,*) Read (nin,*) n Allocate (ap((n*(n+1))/2),s(n)) ! Read the upper or lower triangular part of the matrix A from ! data file 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 ! Print the matrix A ! ifail: behaviour on error exit ! =0 for hard exit, =1 for quiet-soft, =-1 for noisy-soft ifail = 0 Call x04ddf(uplo,'Non-unit diagonal',n,ap,'Bracketed','1P,E10.2', & 'Matrix A','Integer',rlabs,'Integer',clabs,80,0,ifail) Write (nout,*) ! Compute diagonal scaling factors ! The NAG name equivalent of zppequ is f07gtf Call zppequ(uplo,n,ap,s,scond,amax,info) If (info>0) Then Write (nout,99999) 'Diagonal element', info, ' of A is non positive' Else ! Print SCOND, AMAX and the scale factors Write (nout,99998) 'SCOND =', scond, ', AMAX =', amax Write (nout,*) Write (nout,*) 'Diagonal scaling factors' Write (nout,99997) s(1:n) Write (nout,*) Flush (nout) ! Compute values close to underflow and overflow small = x02amf()/(x02ajf()*real(x02bhf(),kind=nag_wp)) big = one/small If ((scondbig)) Then ! Scale A If (uplo=='U') Then ! The NAG name equivalent of zdscal is f06jdf jj = 1 Do j = 1, n Call zdscal(j,s(j),ap(jj),1) Call f06kcf(j,s,1,ap(jj),1) jj = jj + j End Do Else If (uplo=='L') Then jj = 1 jinc = n Do j = 1, n Call zdscal(jinc,s(j),ap(jj),1) Call f06kcf(jinc,s(j),1,ap(jj),1) jj = jj + jinc jinc = jinc - 1 End Do End If ! Print the scaled matrix ifail = 0 Call x04ddf(uplo,'Non-unit diagonal',n,ap,'Bracketed','F8.4', & 'Scaled matrix','Integer',rlabs,'Integer',clabs,80,0,ifail) End If End If 99999 Format (1X,A,I4,A) 99998 Format (1X,2(A,1P,E8.1)) 99997 Format ((1X,1P,7E11.1)) End Program f07gtfe