[325] | 1 | ! |
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| 2 | ! subroutines for PCG or SOR solvers |
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| 3 | ! (used if the ISML library is not available) |
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| 4 | ! |
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| 5 | ! linrg |
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| 6 | ! gauss |
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| 7 | ! vmov |
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| 8 | ! desremopt |
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| 9 | ! dtrsv |
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| 10 | ! dger |
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| 11 | ! xerbla |
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| 12 | ! lsame |
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| 13 | ! folr (empty) |
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| 14 | ! |
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[343] | 15 | !!---------------------------------------------------------------------- |
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| 16 | !! OPA 9.0 , LOCEAN-IPSL (2005) |
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[719] | 17 | !! $Header$ |
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[343] | 18 | !! This software is governed by the CeCILL licence see modipsl/doc/NEMO_CeCILL.txt |
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| 19 | !!---------------------------------------------------------------------- |
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[325] | 20 | SUBROUTINE linrg(kn,pa,klda,painv,kldainv) |
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| 21 | |
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| 22 | !! compute inverse matrix |
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| 23 | |
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| 24 | IMPLICIT NONE |
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| 25 | INTEGER kn,klda,kldainv |
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| 26 | REAL (kind=8) :: pa(kn,kn),painv(kn,kn) |
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| 27 | REAL (kind=8) :: zb(kn,kn) |
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| 28 | REAL (kind=8) :: zv(kn) |
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| 29 | INTEGER iplin(kn) |
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| 30 | INTEGER ji |
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| 31 | |
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| 32 | IF( kn /= klda .OR. kn /= kldainv ) THEN |
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| 33 | write(0,*)'change your parameters' |
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| 34 | STOP |
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| 35 | ENDIF |
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| 36 | |
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| 37 | CALL vmov( kn*kn, pa, painv ) |
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| 38 | |
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| 39 | CALL gauss( kn, painv, iplin, zv ) |
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| 40 | |
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| 41 | zb(:,:) = 0.e0 |
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| 42 | DO ji = 1, kn |
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| 43 | zb(ji,ji) = 1.e0 |
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| 44 | CALL desremopt( kn, painv, iplin, zb(1,ji), zb(1,ji), zv ) |
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| 45 | END DO |
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| 46 | CALL vmov( kn*kn, zb, painv ) |
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| 47 | |
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| 48 | END SUBROUTINE linrg |
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| 49 | !--------------------------------------------------------- |
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| 50 | SUBROUTINE gauss(kn,pa,kplin,pv) |
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| 51 | |
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| 52 | IMPLICIT NONE |
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| 53 | INTEGER kn |
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| 54 | INTEGER ji,jj,jk |
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| 55 | INTEGER ik,ipp |
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| 56 | REAL (kind=8) :: pa(kn,kn),pv(kn) |
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| 57 | !! REAL (kind=8) :: zpivmax,zalpha |
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| 58 | REAL (kind=8) :: zalpha |
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| 59 | INTEGER kplin(kn) |
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| 60 | INTEGER isamax |
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| 61 | EXTERNAL isamax |
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| 62 | |
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| 63 | ! factorisation de Gauss de la matrice a avec pivot partiel . |
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| 64 | ! initialisation des pointeurs . |
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| 65 | DO ji=1,kn |
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| 66 | kplin(ji)=ji |
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| 67 | END DO |
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| 68 | DO jk=1,kn-1 |
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| 69 | ! recherche du pivot maximal . |
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| 70 | !! ik=jk |
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| 71 | !! zpivmax=dabs(pa(jk,jk)) |
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| 72 | !! DO ji=jk,kn |
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| 73 | !! IF(dabs(pa(ji,jk)) > zpivmax) THEN |
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| 74 | !! zpivmax=dabs(pa(ji,jk)) |
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| 75 | !! ik=ji |
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| 76 | !! ENDIF |
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| 77 | !! END DO |
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| 78 | ik=isamax( kn-jk+1, pa(jk,jk) )+jk-1 |
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| 79 | ! permutation de la ligne jk et de la ligne ik . |
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| 80 | IF(jk == 58) THEN |
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| 81 | PRINT *,'matrix ',(pa(jk,ji),ji=1,kn) |
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| 82 | PRINT *,' pivot ',ik,kplin(ik),kplin(jk) |
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| 83 | ENDIF |
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| 84 | ipp=kplin(ik) |
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| 85 | kplin(ik)=kplin(jk) |
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| 86 | kplin(jk)=ipp |
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| 87 | DO jj=1,kn |
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| 88 | pv(jj)=pa(ik,jj) |
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| 89 | pa(ik,jj)=pa(jk,jj) |
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| 90 | pa(jk,jj)=pv(jj) |
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| 91 | END DO |
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| 92 | IF(jk == 58) THEN |
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| 93 | PRINT *,'matrix ',(pa(jk,ji),ji=1,kn) |
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| 94 | PRINT *,' pivot ',ik,kplin(ik),kplin(jk) |
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| 95 | ENDIF |
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| 96 | ! calcul des coefficients de la colonne k ligne a ligne . |
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| 97 | DO ji=jk+1,kn |
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| 98 | IF(pa(jk,jk) == 0) THEN |
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| 99 | PRINT *,'probleme diagonale nulle',jk,pa(jk,jk) |
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| 100 | pa(ji,jk)=pa(ji,jk)/1.E-20 |
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| 101 | ENDIF |
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| 102 | IF(pa(jk,jk) /= 0) pa(ji,jk)=pa(ji,jk)/pa(jk,jk) |
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| 103 | END DO |
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| 104 | !! DO ji=jk+1,kn |
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| 105 | !! DO jj=jk+1,kn |
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| 106 | !! pa(ji,jj)=pa(ji,jj)-pa(ji,jk)*pa(jk,jj) |
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| 107 | !! END DO |
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| 108 | !! END DO |
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| 109 | zalpha=-1. |
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| 110 | CALL dger(kn-jk,kn-jk,zalpha,pa(jk+1,jk),1,pa(jk,jk+1),kn, & |
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| 111 | pa(jk+1,jk+1),kn) |
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| 112 | END DO |
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| 113 | |
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| 114 | END SUBROUTINE gauss |
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| 115 | !--------------------------------------------------------- |
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| 116 | FUNCTION isamax( I, X ) |
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| 117 | DIMENSION X(I) |
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| 118 | ISAMAX = 0 |
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| 119 | XMIN = -1e+50 |
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| 120 | DO N = 1, I |
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| 121 | IF(ABS(X(N)) > XMIN ) THEN |
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| 122 | XMIN = X(N) |
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| 123 | ISAMAX = N |
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| 124 | ENDIF |
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| 125 | END DO |
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| 126 | END FUNCTION isamax |
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| 127 | !--------------------------------------------------------- |
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| 128 | SUBROUTINE vmov(kn,px,py) |
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| 129 | |
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| 130 | IMPLICIT NONE |
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| 131 | INTEGER kn |
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| 132 | REAL (kind=8) :: px(kn),py(kn) |
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| 133 | INTEGER ji |
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| 134 | |
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| 135 | DO ji=1,kn |
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| 136 | py(ji)=px(ji) |
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| 137 | END DO |
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| 138 | |
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| 139 | END SUBROUTINE vmov |
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| 140 | !--------------------------------------------------------- |
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| 141 | subroutine desremopt(n,a,plin,y,x,v) |
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| 142 | implicit none |
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| 143 | integer n,i, j0 |
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| 144 | !! integer n,i,j,j0 |
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| 145 | real (kind=8) :: a(n,n),x(n),y(n),v(n) |
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| 146 | integer plin(n) |
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| 147 | ! descente remontee du systeme . |
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| 148 | ! initialisation du vecteur resultat . |
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| 149 | ! prise en compte de la permutation des lignes . |
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| 150 | do i=1,n |
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| 151 | v(i)=y(plin(i)) |
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| 152 | end do |
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| 153 | do i=1,n |
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| 154 | if(v(i) /= 0.) then |
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| 155 | j0=i-1 |
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| 156 | goto 1 |
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| 157 | endif |
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| 158 | end do |
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| 159 | 1 continue |
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| 160 | ! descente du systeme L v = v , L est a diagonale unitaire . |
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| 161 | !! do j=j0+1,n |
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| 162 | !! do i=j+1,n |
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| 163 | !! v(i)=v(i)-a(i,j)*v(j) |
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| 164 | !! end do |
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| 165 | !! end do |
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| 166 | call dtrsv('L','N','U',n-j0,a(j0+1,j0+1),n,v(j0+1),1) |
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| 167 | ! remontee du systeme U v = v . |
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| 168 | !! do j=n,1,-1 |
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| 169 | !! v(j)=v(j)/a(j,j) |
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| 170 | !! do i=1,j-1 |
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| 171 | !! v(i)=v(i)-a(i,j)*v(j) |
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| 172 | !! end do |
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| 173 | !! end do |
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| 174 | call dtrsv('U','N','N',n,a,n,v,1) |
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| 175 | ! prise en compte de la permutation des colonnes . |
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| 176 | do i=1,n |
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| 177 | x(i)=v(i) |
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| 178 | end do |
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| 179 | |
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| 180 | end SUBROUTINE desremopt |
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| 181 | !--------------------------------------------------------- |
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| 182 | SUBROUTINE DTRSV ( UPLO, TRANS, DIAG, N, A, LDA, X, INCX ) |
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| 183 | !! .. Scalar Arguments .. |
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| 184 | INTEGER INCX, LDA, N |
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| 185 | CHARACTER (len=1) :: DIAG, TRANS, UPLO |
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| 186 | !! .. Array Arguments .. |
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| 187 | ! DOUBLE PRECISION A( LDA, * ), X( * ) |
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| 188 | REAL (kind=8) :: A( LDA, * ), X( * ) |
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| 189 | !! .. |
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| 190 | |
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| 191 | !! Purpose |
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| 192 | !! ======= |
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| 193 | |
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| 194 | !! DTRSV solves one of the systems of equations |
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| 195 | |
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| 196 | !! A*x = b, or A'*x = b, |
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| 197 | |
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| 198 | !! where b and x are n element vectors and A is an n by n unit, or |
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| 199 | !! non-unit, upper or lower triangular matrix. |
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| 200 | |
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| 201 | !! No test for singularity or near-singularity is included in this |
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| 202 | !! routine. Such tests must be performed before calling this routine. |
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| 203 | |
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| 204 | !! Parameters |
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| 205 | !! ========== |
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| 206 | |
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| 207 | !! UPLO - CHARACTER*1. |
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| 208 | !! On entry, UPLO specifies whether the matrix is an upper or |
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| 209 | !! lower triangular matrix as follows: |
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| 210 | |
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| 211 | !! UPLO = 'U' or 'u' A is an upper triangular matrix. |
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| 212 | |
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| 213 | !! UPLO = 'L' or 'l' A is a lower triangular matrix. |
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| 214 | |
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| 215 | !! Unchanged on exit. |
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| 216 | |
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| 217 | !! TRANS - CHARACTER*1. |
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| 218 | !! On entry, TRANS specifies the equations to be solved as |
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| 219 | !! follows: |
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| 220 | |
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| 221 | !! TRANS = 'N' or 'n' A*x = b. |
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| 222 | |
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| 223 | !! TRANS = 'T' or 't' A'*x = b. |
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| 224 | |
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| 225 | !! TRANS = 'C' or 'c' A'*x = b. |
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| 226 | |
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| 227 | !! Unchanged on exit. |
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| 228 | |
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| 229 | !! DIAG - CHARACTER*1. |
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| 230 | !! On entry, DIAG specifies whether or not A is unit |
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| 231 | !! triangular as follows: |
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| 232 | |
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| 233 | !! DIAG = 'U' or 'u' A is assumed to be unit triangular. |
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| 234 | |
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| 235 | !! DIAG = 'N' or 'n' A is not assumed to be unit |
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| 236 | !! triangular. |
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| 237 | |
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| 238 | !! Unchanged on exit. |
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| 239 | |
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| 240 | !! N - INTEGER. |
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| 241 | !! On entry, N specifies the order of the matrix A. |
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| 242 | !! N must be at least zero. |
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| 243 | !! Unchanged on exit. |
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| 244 | |
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| 245 | !! A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). |
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| 246 | !! Before entry with UPLO = 'U' or 'u', the leading n by n |
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| 247 | !! upper triangular part of the array A must contain the upper |
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| 248 | !! triangular matrix and the strictly lower triangular part of |
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| 249 | !! A is not referenced. |
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| 250 | !! Before entry with UPLO = 'L' or 'l', the leading n by n |
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| 251 | !! lower triangular part of the array A must contain the lower |
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| 252 | !! triangular matrix and the strictly upper triangular part of |
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| 253 | !! A is not referenced. |
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| 254 | !! Note that when DIAG = 'U' or 'u', the diagonal elements of |
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| 255 | !! A are not referenced either, but are assumed to be unity. |
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| 256 | !! Unchanged on exit. |
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| 257 | |
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| 258 | !! LDA - INTEGER. |
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| 259 | !! On entry, LDA specifies the first dimension of A as declared |
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| 260 | !! in the calling (sub) program. LDA must be at least |
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| 261 | !! max( 1, n ). |
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| 262 | !! Unchanged on exit. |
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| 263 | |
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| 264 | !! X - DOUBLE PRECISION array of dimension at least |
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| 265 | !! ( 1 + ( n - 1 )*abs( INCX ) ). |
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| 266 | !! Before entry, the incremented array X must contain the n |
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| 267 | !! element right-hand side vector b. On exit, X is overwritten |
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| 268 | !! with the solution vector x. |
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| 269 | |
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| 270 | !! INCX - INTEGER. |
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| 271 | !! On entry, INCX specifies the increment for the elements of |
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| 272 | !! X. INCX must not be zero. |
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| 273 | !! Unchanged on exit. |
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| 274 | |
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| 275 | |
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| 276 | !! Level 2 Blas routine. |
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| 277 | |
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| 278 | !! -- Written on 22-October-1986. |
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| 279 | !! Jack Dongarra, Argonne National Lab. |
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| 280 | !! Jeremy Du Croz, Nag Central Office. |
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| 281 | !! Sven Hammarling, Nag Central Office. |
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| 282 | !! Richard Hanson, Sandia National Labs. |
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| 283 | |
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| 284 | |
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| 285 | !! .. Parameters .. |
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| 286 | ! DOUBLE PRECISION ZERO |
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| 287 | ! PARAMETER ( ZERO = 0.0D+0 ) |
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| 288 | REAL (kind=8) :: ZERO |
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| 289 | PARAMETER ( ZERO = 0.0 ) |
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| 290 | !! .. Local Scalars .. |
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| 291 | ! DOUBLE PRECISION TEMP |
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| 292 | REAL (kind=8) :: TEMP |
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| 293 | INTEGER I, INFO, IX, J, JX, KX |
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| 294 | LOGICAL NOUNIT |
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| 295 | !! .. External Functions .. |
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| 296 | LOGICAL LSAME |
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| 297 | EXTERNAL LSAME |
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| 298 | !! .. External Subroutines .. |
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| 299 | EXTERNAL XERBLA |
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| 300 | !! .. Intrinsic Functions .. |
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| 301 | INTRINSIC MAX |
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| 302 | !! .. |
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| 303 | !! .. Executable Statements .. |
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| 304 | |
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| 305 | !! Test the input parameters. |
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| 306 | |
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| 307 | INFO = 0 |
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| 308 | IF ( .NOT.LSAME( UPLO , 'U' ).AND. & |
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| 309 | .NOT.LSAME( UPLO , 'L' ) )THEN |
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| 310 | INFO = 1 |
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| 311 | ELSE IF( .NOT.LSAME( TRANS, 'N' ).AND. & |
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| 312 | .NOT.LSAME( TRANS, 'T' ).AND. & |
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| 313 | .NOT.LSAME( TRANS, 'C' ) )THEN |
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| 314 | INFO = 2 |
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| 315 | ELSE IF( .NOT.LSAME( DIAG , 'U' ).AND. & |
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| 316 | .NOT.LSAME( DIAG , 'N' ) )THEN |
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| 317 | INFO = 3 |
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| 318 | ELSE IF( N < 0 )THEN |
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| 319 | INFO = 4 |
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| 320 | ELSE IF( LDA < MAX( 1, N ) )THEN |
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| 321 | INFO = 6 |
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| 322 | ELSE IF( INCX == 0 )THEN |
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| 323 | INFO = 8 |
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| 324 | END IF |
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| 325 | IF( INFO /= 0 )THEN |
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| 326 | CALL XERBLA( 'DTRSV ', INFO ) |
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| 327 | RETURN |
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| 328 | END IF |
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| 329 | |
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| 330 | !! Quick return if possible. |
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| 331 | |
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| 332 | IF( N == 0 ) RETURN |
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| 333 | |
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| 334 | NOUNIT = LSAME( DIAG, 'N' ) |
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| 335 | |
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| 336 | !! Set up the start point in X if the increment is not unity. This |
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| 337 | !! will be ( N - 1 )*INCX too small for descending loops. |
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| 338 | |
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| 339 | IF( INCX <= 0 )THEN |
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| 340 | KX = 1 - ( N - 1 )*INCX |
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| 341 | ELSE IF( INCX /= 1 )THEN |
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| 342 | KX = 1 |
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| 343 | END IF |
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| 344 | |
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| 345 | !! Start the operations. In this version the elements of A are |
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| 346 | !! accessed sequentially with one pass through A. |
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| 347 | |
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| 348 | IF( LSAME( TRANS, 'N' ) )THEN |
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| 349 | |
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| 350 | !! Form x := inv( A )*x. |
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| 351 | |
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| 352 | IF( LSAME( UPLO, 'U' ) )THEN |
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| 353 | IF( INCX == 1 )THEN |
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| 354 | DO 20, J = N, 1, -1 |
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| 355 | IF( X( J ) /= ZERO )THEN |
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| 356 | IF( NOUNIT ) X( J ) = X( J )/A( J, J ) |
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| 357 | TEMP = X( J ) |
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| 358 | DO 10, I = J - 1, 1, -1 |
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| 359 | X( I ) = X( I ) - TEMP*A( I, J ) |
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| 360 | 10 CONTINUE |
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| 361 | END IF |
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| 362 | 20 CONTINUE |
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| 363 | ELSE |
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| 364 | JX = KX + ( N - 1 )*INCX |
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| 365 | DO 40, J = N, 1, -1 |
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| 366 | IF( X( JX ) /= ZERO )THEN |
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| 367 | IF( NOUNIT ) X( JX ) = X( JX )/A( J, J ) |
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| 368 | TEMP = X( JX ) |
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| 369 | IX = JX |
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| 370 | DO 30, I = J - 1, 1, -1 |
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| 371 | IX = IX - INCX |
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| 372 | X( IX ) = X( IX ) - TEMP*A( I, J ) |
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| 373 | 30 CONTINUE |
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| 374 | END IF |
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| 375 | JX = JX - INCX |
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| 376 | 40 CONTINUE |
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| 377 | END IF |
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| 378 | ELSE |
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| 379 | IF( INCX == 1 )THEN |
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| 380 | DO 60, J = 1, N |
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| 381 | IF( X( J ) /= ZERO )THEN |
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| 382 | IF( NOUNIT ) X( J ) = X( J )/A( J, J ) |
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| 383 | TEMP = X( J ) |
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| 384 | DO 50, I = J + 1, N |
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| 385 | X( I ) = X( I ) - TEMP*A( I, J ) |
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| 386 | 50 CONTINUE |
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| 387 | END IF |
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| 388 | 60 CONTINUE |
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| 389 | ELSE |
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| 390 | JX = KX |
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| 391 | DO 80, J = 1, N |
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| 392 | IF( X( JX ) /= ZERO )THEN |
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| 393 | IF( NOUNIT ) X( JX ) = X( JX )/A( J, J ) |
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| 394 | TEMP = X( JX ) |
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| 395 | IX = JX |
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| 396 | DO 70, I = J + 1, N |
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| 397 | IX = IX + INCX |
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| 398 | X( IX ) = X( IX ) - TEMP*A( I, J ) |
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| 399 | 70 CONTINUE |
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| 400 | END IF |
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| 401 | JX = JX + INCX |
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| 402 | 80 CONTINUE |
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| 403 | END IF |
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| 404 | END IF |
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| 405 | ELSE |
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| 406 | |
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| 407 | !! Form x := inv( A' )*x. |
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| 408 | |
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| 409 | IF( LSAME( UPLO, 'U' ) )THEN |
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| 410 | IF( INCX == 1 )THEN |
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| 411 | DO 100, J = 1, N |
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| 412 | TEMP = X( J ) |
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| 413 | DO 90, I = 1, J - 1 |
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| 414 | TEMP = TEMP - A( I, J )*X( I ) |
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| 415 | 90 CONTINUE |
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| 416 | IF( NOUNIT ) TEMP = TEMP/A( J, J ) |
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| 417 | X( J ) = TEMP |
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| 418 | 100 CONTINUE |
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| 419 | ELSE |
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| 420 | JX = KX |
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| 421 | DO 120, J = 1, N |
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| 422 | TEMP = X( JX ) |
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| 423 | IX = KX |
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| 424 | DO 110, I = 1, J - 1 |
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| 425 | TEMP = TEMP - A( I, J )*X( IX ) |
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| 426 | IX = IX + INCX |
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| 427 | 110 CONTINUE |
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| 428 | IF( NOUNIT ) TEMP = TEMP/A( J, J ) |
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| 429 | X( JX ) = TEMP |
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| 430 | JX = JX + INCX |
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| 431 | 120 CONTINUE |
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| 432 | END IF |
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| 433 | ELSE |
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| 434 | IF( INCX == 1 )THEN |
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| 435 | DO 140, J = N, 1, -1 |
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| 436 | TEMP = X( J ) |
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| 437 | DO 130, I = N, J + 1, -1 |
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| 438 | TEMP = TEMP - A( I, J )*X( I ) |
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| 439 | 130 CONTINUE |
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| 440 | IF( NOUNIT ) TEMP = TEMP/A( J, J ) |
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| 441 | X( J ) = TEMP |
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| 442 | 140 CONTINUE |
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| 443 | ELSE |
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| 444 | KX = KX + ( N - 1 )*INCX |
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| 445 | JX = KX |
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| 446 | DO 160, J = N, 1, -1 |
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| 447 | TEMP = X( JX ) |
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| 448 | IX = KX |
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| 449 | DO 150, I = N, J + 1, -1 |
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| 450 | TEMP = TEMP - A( I, J )*X( IX ) |
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| 451 | IX = IX - INCX |
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| 452 | 150 CONTINUE |
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| 453 | IF( NOUNIT ) TEMP = TEMP/A( J, J ) |
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| 454 | X( JX ) = TEMP |
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| 455 | JX = JX - INCX |
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| 456 | 160 CONTINUE |
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| 457 | END IF |
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| 458 | END IF |
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| 459 | END IF |
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| 460 | |
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| 461 | END SUBROUTINE DTRSV |
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| 462 | !--------------------------------------------------------- |
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| 463 | SUBROUTINE DGER ( M, N, ALPHA, X, INCX, Y, INCY, A, LDA ) |
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| 464 | !! .. Scalar Arguments .. |
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| 465 | ! DOUBLE PRECISION ALPHA |
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| 466 | REAL (kind=8) :: ALPHA |
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| 467 | INTEGER INCX, INCY, LDA, M, N |
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| 468 | !! .. Array Arguments .. |
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| 469 | ! DOUBLE PRECISION A( LDA, * ), X( * ), Y( * ) |
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| 470 | REAL (kind=8) :: A( LDA, * ), X( * ), Y( * ) |
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| 471 | !! .. |
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| 472 | |
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| 473 | !! Purpose |
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| 474 | !! ======= |
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| 475 | |
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| 476 | !! DGER performs the rank 1 operation |
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| 477 | |
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| 478 | !! A := alpha*x*y' + A, |
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| 479 | |
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| 480 | !! where alpha is a scalar, x is an m element vector, y is an n element |
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| 481 | !! vector and A is an m by n matrix. |
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| 482 | |
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| 483 | !! Parameters |
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| 484 | !! ========== |
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| 485 | |
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| 486 | !! M - INTEGER. |
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| 487 | !! On entry, M specifies the number of rows of the matrix A. |
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| 488 | !! M must be at least zero. |
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| 489 | !! Unchanged on exit. |
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| 490 | |
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| 491 | !! N - INTEGER. |
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| 492 | !! On entry, N specifies the number of columns of the matrix A. |
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| 493 | !! N must be at least zero. |
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| 494 | !! Unchanged on exit. |
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| 495 | |
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| 496 | !! ALPHA - DOUBLE PRECISION. |
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| 497 | !! On entry, ALPHA specifies the scalar alpha. |
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| 498 | !! Unchanged on exit. |
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| 499 | |
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| 500 | !! X - DOUBLE PRECISION array of dimension at least |
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| 501 | !! ( 1 + ( m - 1 )*abs( INCX ) ). |
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| 502 | !! Before entry, the incremented array X must contain the m |
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| 503 | !! element vector x. |
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| 504 | !! Unchanged on exit. |
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| 505 | |
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| 506 | !! INCX - INTEGER. |
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| 507 | !! On entry, INCX specifies the increment for the elements of |
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| 508 | !! X. INCX must not be zero. |
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| 509 | !! Unchanged on exit. |
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| 510 | |
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| 511 | !! Y - DOUBLE PRECISION array of dimension at least |
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| 512 | !! ( 1 + ( n - 1 )*abs( INCY ) ). |
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| 513 | !! Before entry, the incremented array Y must contain the n |
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| 514 | !! element vector y. |
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| 515 | !! Unchanged on exit. |
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| 516 | |
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| 517 | !! INCY - INTEGER. |
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| 518 | !! On entry, INCY specifies the increment for the elements of |
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| 519 | !! Y. INCY must not be zero. |
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| 520 | !! Unchanged on exit. |
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| 521 | |
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| 522 | !! A - DOUBLE PRECISION array of DIMENSION ( LDA, n ). |
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| 523 | !! Before entry, the leading m by n part of the array A must |
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| 524 | !! contain the matrix of coefficients. On exit, A is |
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| 525 | !! overwritten by the updated matrix. |
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| 526 | |
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| 527 | !! LDA - INTEGER. |
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| 528 | !! On entry, LDA specifies the first dimension of A as declared |
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| 529 | !! in the calling (sub) program. LDA must be at least |
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| 530 | !! max( 1, m ). |
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| 531 | !! Unchanged on exit. |
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| 532 | |
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| 533 | |
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| 534 | !! Level 2 Blas routine. |
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| 535 | |
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| 536 | !! -- Written on 22-October-1986. |
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| 537 | !! Jack Dongarra, Argonne National Lab. |
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| 538 | !! Jeremy Du Croz, Nag Central Office. |
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| 539 | !! Sven Hammarling, Nag Central Office. |
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| 540 | !! Richard Hanson, Sandia National Labs. |
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| 541 | |
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| 542 | |
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| 543 | !! .. Parameters .. |
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| 544 | ! DOUBLE PRECISION ZERO |
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| 545 | ! PARAMETER ( ZERO = 0.0D+0 ) |
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| 546 | REAL (kind=8) :: ZERO |
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| 547 | PARAMETER ( ZERO = 0.0 ) |
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| 548 | !! .. Local Scalars .. |
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| 549 | ! DOUBLE PRECISION TEMP |
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| 550 | REAL (kind=8) :: TEMP |
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| 551 | INTEGER I, INFO, IX, J, JY, KX |
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| 552 | !! .. External Subroutines .. |
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| 553 | EXTERNAL XERBLA |
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| 554 | !! .. Intrinsic Functions .. |
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| 555 | INTRINSIC MAX |
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| 556 | !! .. |
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| 557 | !! .. Executable Statements .. |
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| 558 | |
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| 559 | !! Test the input parameters. |
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| 560 | |
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| 561 | INFO = 0 |
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| 562 | IF ( M < 0 )THEN |
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| 563 | INFO = 1 |
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| 564 | ELSE IF( N < 0 )THEN |
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| 565 | INFO = 2 |
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| 566 | ELSE IF( INCX == 0 )THEN |
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| 567 | INFO = 5 |
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| 568 | ELSE IF( INCY == 0 )THEN |
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| 569 | INFO = 7 |
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| 570 | ELSE IF( LDA < MAX( 1, M ) )THEN |
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| 571 | INFO = 9 |
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| 572 | END IF |
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| 573 | IF( INFO /= 0 )THEN |
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| 574 | CALL XERBLA( 'DGER ', INFO ) |
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| 575 | RETURN |
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| 576 | END IF |
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| 577 | |
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| 578 | !! Quick return if possible. |
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| 579 | |
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| 580 | IF( ( M == 0 ).OR.( N == 0 ).OR.( ALPHA == ZERO ) ) & |
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| 581 | RETURN |
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| 582 | |
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| 583 | !! Start the operations. In this version the elements of A are |
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| 584 | !! accessed sequentially with one pass through A. |
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| 585 | |
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| 586 | IF( INCY > 0 )THEN |
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| 587 | JY = 1 |
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| 588 | ELSE |
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| 589 | JY = 1 - ( N - 1 )*INCY |
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| 590 | END IF |
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| 591 | IF( INCX == 1 )THEN |
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| 592 | DO 20, J = 1, N |
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| 593 | IF( Y( JY ) /= ZERO )THEN |
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| 594 | TEMP = ALPHA*Y( JY ) |
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| 595 | DO 10, I = 1, M |
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| 596 | A( I, J ) = A( I, J ) + X( I )*TEMP |
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| 597 | 10 CONTINUE |
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| 598 | END IF |
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| 599 | JY = JY + INCY |
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| 600 | 20 CONTINUE |
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| 601 | ELSE |
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| 602 | IF( INCX > 0 )THEN |
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| 603 | KX = 1 |
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| 604 | ELSE |
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| 605 | KX = 1 - ( M - 1 )*INCX |
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| 606 | END IF |
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| 607 | DO 40, J = 1, N |
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| 608 | IF( Y( JY ) /= ZERO )THEN |
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| 609 | TEMP = ALPHA*Y( JY ) |
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| 610 | IX = KX |
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| 611 | DO 30, I = 1, M |
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| 612 | A( I, J ) = A( I, J ) + X( IX )*TEMP |
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| 613 | IX = IX + INCX |
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| 614 | 30 CONTINUE |
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| 615 | END IF |
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| 616 | JY = JY + INCY |
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| 617 | 40 CONTINUE |
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| 618 | END IF |
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| 619 | |
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| 620 | END SUBROUTINE DGER |
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| 621 | !--------------------------------------------------------- |
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| 622 | SUBROUTINE XERBLA ( SRNAME, INFO ) |
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| 623 | !! .. Scalar Arguments .. |
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| 624 | INTEGER INFO |
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| 625 | CHARACTER (len=6) :: SRNAME |
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| 626 | !! .. |
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| 627 | |
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| 628 | !! Purpose |
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| 629 | !! ======= |
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| 630 | |
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| 631 | !! XERBLA is an error handler for the Level 2 BLAS routines. |
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| 632 | |
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| 633 | !! It is called by the Level 2 BLAS routines if an input parameter is |
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| 634 | !! invalid. |
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| 635 | |
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| 636 | !! Installers should consider modifying the STOP statement in order to |
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| 637 | !! call system-specific exception-handling facilities. |
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| 638 | |
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| 639 | !! Parameters |
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| 640 | !! ========== |
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| 641 | |
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| 642 | !! SRNAME - CHARACTER*6. |
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| 643 | !! On entry, SRNAME specifies the name of the routine which |
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| 644 | !! called XERBLA. |
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| 645 | |
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| 646 | !! INFO - INTEGER. |
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| 647 | !! On entry, INFO specifies the position of the invalid |
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| 648 | !! parameter in the parameter-list of the calling routine. |
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| 649 | |
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| 650 | |
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| 651 | !! Auxiliary routine for Level 2 Blas. |
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| 652 | |
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| 653 | !! Written on 20-July-1986. |
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| 654 | |
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| 655 | !! .. Executable Statements .. |
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| 656 | |
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| 657 | WRITE (*,99999) SRNAME, INFO |
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| 658 | |
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| 659 | STOP |
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| 660 | |
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| 661 | 99999 FORMAT ( ' ** On entry to ', A6, ' parameter number ', I2, & |
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| 662 | ' had an illegal value' ) |
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| 663 | |
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| 664 | END SUBROUTINE XERBLA |
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| 665 | !----------------------------------------------------------- |
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| 666 | FUNCTION lsame( c1, c2 ) |
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| 667 | logical lsame |
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| 668 | CHARACTER (len=*), INTENT(in) :: c1, c2 |
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| 669 | IF( c1 == c2 ) THEN |
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| 670 | lsame=.TRUE. |
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| 671 | ELSE |
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| 672 | lsame=.FALSE. |
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| 673 | ENDIF |
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| 674 | END FUNCTION lsame |
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