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authorjofret2009-04-28 07:17:00 +0000
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- SUBROUTINE DLATRS( UPLO, TRANS, DIAG, NORMIN, N, A, LDA, X, SCALE,
- $ CNORM, INFO )
-*
-* -- LAPACK auxiliary routine (version 3.1) --
-* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd..
-* November 2006
-*
-* .. Scalar Arguments ..
- CHARACTER DIAG, NORMIN, TRANS, UPLO
- INTEGER INFO, LDA, N
- DOUBLE PRECISION SCALE
-* ..
-* .. Array Arguments ..
- DOUBLE PRECISION A( LDA, * ), CNORM( * ), X( * )
-* ..
-*
-* Purpose
-* =======
-*
-* DLATRS solves one of the triangular systems
-*
-* A *x = s*b or A'*x = s*b
-*
-* with scaling to prevent overflow. Here A is an upper or lower
-* triangular matrix, A' denotes the transpose of A, x and b are
-* n-element vectors, and s is a scaling factor, usually less than
-* or equal to 1, chosen so that the components of x will be less than
-* the overflow threshold. If the unscaled problem will not cause
-* overflow, the Level 2 BLAS routine DTRSV is called. If the matrix A
-* is singular (A(j,j) = 0 for some j), then s is set to 0 and a
-* non-trivial solution to A*x = 0 is returned.
-*
-* Arguments
-* =========
-*
-* UPLO (input) CHARACTER*1
-* Specifies whether the matrix A is upper or lower triangular.
-* = 'U': Upper triangular
-* = 'L': Lower triangular
-*
-* TRANS (input) CHARACTER*1
-* Specifies the operation applied to A.
-* = 'N': Solve A * x = s*b (No transpose)
-* = 'T': Solve A'* x = s*b (Transpose)
-* = 'C': Solve A'* x = s*b (Conjugate transpose = Transpose)
-*
-* DIAG (input) CHARACTER*1
-* Specifies whether or not the matrix A is unit triangular.
-* = 'N': Non-unit triangular
-* = 'U': Unit triangular
-*
-* NORMIN (input) CHARACTER*1
-* Specifies whether CNORM has been set or not.
-* = 'Y': CNORM contains the column norms on entry
-* = 'N': CNORM is not set on entry. On exit, the norms will
-* be computed and stored in CNORM.
-*
-* N (input) INTEGER
-* The order of the matrix A. N >= 0.
-*
-* A (input) DOUBLE PRECISION array, dimension (LDA,N)
-* The triangular matrix A. If UPLO = 'U', the leading n by n
-* upper triangular part of the array A contains the upper
-* triangular matrix, and the strictly lower triangular part of
-* A is not referenced. If UPLO = 'L', the leading n by n lower
-* triangular part of the array A contains the lower triangular
-* matrix, and the strictly upper triangular part of A is not
-* referenced. If DIAG = 'U', the diagonal elements of A are
-* also not referenced and are assumed to be 1.
-*
-* LDA (input) INTEGER
-* The leading dimension of the array A. LDA >= max (1,N).
-*
-* X (input/output) DOUBLE PRECISION array, dimension (N)
-* On entry, the right hand side b of the triangular system.
-* On exit, X is overwritten by the solution vector x.
-*
-* SCALE (output) DOUBLE PRECISION
-* The scaling factor s for the triangular system
-* A * x = s*b or A'* x = s*b.
-* If SCALE = 0, the matrix A is singular or badly scaled, and
-* the vector x is an exact or approximate solution to A*x = 0.
-*
-* CNORM (input or output) DOUBLE PRECISION array, dimension (N)
-*
-* If NORMIN = 'Y', CNORM is an input argument and CNORM(j)
-* contains the norm of the off-diagonal part of the j-th column
-* of A. If TRANS = 'N', CNORM(j) must be greater than or equal
-* to the infinity-norm, and if TRANS = 'T' or 'C', CNORM(j)
-* must be greater than or equal to the 1-norm.
-*
-* If NORMIN = 'N', CNORM is an output argument and CNORM(j)
-* returns the 1-norm of the offdiagonal part of the j-th column
-* of A.
-*
-* INFO (output) INTEGER
-* = 0: successful exit
-* < 0: if INFO = -k, the k-th argument had an illegal value
-*
-* Further Details
-* ======= =======
-*
-* A rough bound on x is computed; if that is less than overflow, DTRSV
-* is called, otherwise, specific code is used which checks for possible
-* overflow or divide-by-zero at every operation.
-*
-* A columnwise scheme is used for solving A*x = b. The basic algorithm
-* if A is lower triangular is
-*
-* x[1:n] := b[1:n]
-* for j = 1, ..., n
-* x(j) := x(j) / A(j,j)
-* x[j+1:n] := x[j+1:n] - x(j) * A[j+1:n,j]
-* end
-*
-* Define bounds on the components of x after j iterations of the loop:
-* M(j) = bound on x[1:j]
-* G(j) = bound on x[j+1:n]
-* Initially, let M(0) = 0 and G(0) = max{x(i), i=1,...,n}.
-*
-* Then for iteration j+1 we have
-* M(j+1) <= G(j) / | A(j+1,j+1) |
-* G(j+1) <= G(j) + M(j+1) * | A[j+2:n,j+1] |
-* <= G(j) ( 1 + CNORM(j+1) / | A(j+1,j+1) | )
-*
-* where CNORM(j+1) is greater than or equal to the infinity-norm of
-* column j+1 of A, not counting the diagonal. Hence
-*
-* G(j) <= G(0) product ( 1 + CNORM(i) / | A(i,i) | )
-* 1<=i<=j
-* and
-*
-* |x(j)| <= ( G(0) / |A(j,j)| ) product ( 1 + CNORM(i) / |A(i,i)| )
-* 1<=i< j
-*
-* Since |x(j)| <= M(j), we use the Level 2 BLAS routine DTRSV if the
-* reciprocal of the largest M(j), j=1,..,n, is larger than
-* max(underflow, 1/overflow).
-*
-* The bound on x(j) is also used to determine when a step in the
-* columnwise method can be performed without fear of overflow. If
-* the computed bound is greater than a large constant, x is scaled to
-* prevent overflow, but if the bound overflows, x is set to 0, x(j) to
-* 1, and scale to 0, and a non-trivial solution to A*x = 0 is found.
-*
-* Similarly, a row-wise scheme is used to solve A'*x = b. The basic
-* algorithm for A upper triangular is
-*
-* for j = 1, ..., n
-* x(j) := ( b(j) - A[1:j-1,j]' * x[1:j-1] ) / A(j,j)
-* end
-*
-* We simultaneously compute two bounds
-* G(j) = bound on ( b(i) - A[1:i-1,i]' * x[1:i-1] ), 1<=i<=j
-* M(j) = bound on x(i), 1<=i<=j
-*
-* The initial values are G(0) = 0, M(0) = max{b(i), i=1,..,n}, and we
-* add the constraint G(j) >= G(j-1) and M(j) >= M(j-1) for j >= 1.
-* Then the bound on x(j) is
-*
-* M(j) <= M(j-1) * ( 1 + CNORM(j) ) / | A(j,j) |
-*
-* <= M(0) * product ( ( 1 + CNORM(i) ) / |A(i,i)| )
-* 1<=i<=j
-*
-* and we can safely call DTRSV if 1/M(n) and 1/G(n) are both greater
-* than max(underflow, 1/overflow).
-*
-* =====================================================================
-*
-* .. Parameters ..
- DOUBLE PRECISION ZERO, HALF, ONE
- PARAMETER ( ZERO = 0.0D+0, HALF = 0.5D+0, ONE = 1.0D+0 )
-* ..
-* .. Local Scalars ..
- LOGICAL NOTRAN, NOUNIT, UPPER
- INTEGER I, IMAX, J, JFIRST, JINC, JLAST
- DOUBLE PRECISION BIGNUM, GROW, REC, SMLNUM, SUMJ, TJJ, TJJS,
- $ TMAX, TSCAL, USCAL, XBND, XJ, XMAX
-* ..
-* .. External Functions ..
- LOGICAL LSAME
- INTEGER IDAMAX
- DOUBLE PRECISION DASUM, DDOT, DLAMCH
- EXTERNAL LSAME, IDAMAX, DASUM, DDOT, DLAMCH
-* ..
-* .. External Subroutines ..
- EXTERNAL DAXPY, DSCAL, DTRSV, XERBLA
-* ..
-* .. Intrinsic Functions ..
- INTRINSIC ABS, MAX, MIN
-* ..
-* .. Executable Statements ..
-*
- INFO = 0
- UPPER = LSAME( UPLO, 'U' )
- NOTRAN = LSAME( TRANS, 'N' )
- NOUNIT = LSAME( DIAG, 'N' )
-*
-* Test the input parameters.
-*
- IF( .NOT.UPPER .AND. .NOT.LSAME( UPLO, 'L' ) ) THEN
- INFO = -1
- ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'T' ) .AND. .NOT.
- $ LSAME( TRANS, 'C' ) ) THEN
- INFO = -2
- ELSE IF( .NOT.NOUNIT .AND. .NOT.LSAME( DIAG, 'U' ) ) THEN
- INFO = -3
- ELSE IF( .NOT.LSAME( NORMIN, 'Y' ) .AND. .NOT.
- $ LSAME( NORMIN, 'N' ) ) THEN
- INFO = -4
- ELSE IF( N.LT.0 ) THEN
- INFO = -5
- ELSE IF( LDA.LT.MAX( 1, N ) ) THEN
- INFO = -7
- END IF
- IF( INFO.NE.0 ) THEN
- CALL XERBLA( 'DLATRS', -INFO )
- RETURN
- END IF
-*
-* Quick return if possible
-*
- IF( N.EQ.0 )
- $ RETURN
-*
-* Determine machine dependent parameters to control overflow.
-*
- SMLNUM = DLAMCH( 'Safe minimum' ) / DLAMCH( 'Precision' )
- BIGNUM = ONE / SMLNUM
- SCALE = ONE
-*
- IF( LSAME( NORMIN, 'N' ) ) THEN
-*
-* Compute the 1-norm of each column, not including the diagonal.
-*
- IF( UPPER ) THEN
-*
-* A is upper triangular.
-*
- DO 10 J = 1, N
- CNORM( J ) = DASUM( J-1, A( 1, J ), 1 )
- 10 CONTINUE
- ELSE
-*
-* A is lower triangular.
-*
- DO 20 J = 1, N - 1
- CNORM( J ) = DASUM( N-J, A( J+1, J ), 1 )
- 20 CONTINUE
- CNORM( N ) = ZERO
- END IF
- END IF
-*
-* Scale the column norms by TSCAL if the maximum element in CNORM is
-* greater than BIGNUM.
-*
- IMAX = IDAMAX( N, CNORM, 1 )
- TMAX = CNORM( IMAX )
- IF( TMAX.LE.BIGNUM ) THEN
- TSCAL = ONE
- ELSE
- TSCAL = ONE / ( SMLNUM*TMAX )
- CALL DSCAL( N, TSCAL, CNORM, 1 )
- END IF
-*
-* Compute a bound on the computed solution vector to see if the
-* Level 2 BLAS routine DTRSV can be used.
-*
- J = IDAMAX( N, X, 1 )
- XMAX = ABS( X( J ) )
- XBND = XMAX
- IF( NOTRAN ) THEN
-*
-* Compute the growth in A * x = b.
-*
- IF( UPPER ) THEN
- JFIRST = N
- JLAST = 1
- JINC = -1
- ELSE
- JFIRST = 1
- JLAST = N
- JINC = 1
- END IF
-*
- IF( TSCAL.NE.ONE ) THEN
- GROW = ZERO
- GO TO 50
- END IF
-*
- IF( NOUNIT ) THEN
-*
-* A is non-unit triangular.
-*
-* Compute GROW = 1/G(j) and XBND = 1/M(j).
-* Initially, G(0) = max{x(i), i=1,...,n}.
-*
- GROW = ONE / MAX( XBND, SMLNUM )
- XBND = GROW
- DO 30 J = JFIRST, JLAST, JINC
-*
-* Exit the loop if the growth factor is too small.
-*
- IF( GROW.LE.SMLNUM )
- $ GO TO 50
-*
-* M(j) = G(j-1) / abs(A(j,j))
-*
- TJJ = ABS( A( J, J ) )
- XBND = MIN( XBND, MIN( ONE, TJJ )*GROW )
- IF( TJJ+CNORM( J ).GE.SMLNUM ) THEN
-*
-* G(j) = G(j-1)*( 1 + CNORM(j) / abs(A(j,j)) )
-*
- GROW = GROW*( TJJ / ( TJJ+CNORM( J ) ) )
- ELSE
-*
-* G(j) could overflow, set GROW to 0.
-*
- GROW = ZERO
- END IF
- 30 CONTINUE
- GROW = XBND
- ELSE
-*
-* A is unit triangular.
-*
-* Compute GROW = 1/G(j), where G(0) = max{x(i), i=1,...,n}.
-*
- GROW = MIN( ONE, ONE / MAX( XBND, SMLNUM ) )
- DO 40 J = JFIRST, JLAST, JINC
-*
-* Exit the loop if the growth factor is too small.
-*
- IF( GROW.LE.SMLNUM )
- $ GO TO 50
-*
-* G(j) = G(j-1)*( 1 + CNORM(j) )
-*
- GROW = GROW*( ONE / ( ONE+CNORM( J ) ) )
- 40 CONTINUE
- END IF
- 50 CONTINUE
-*
- ELSE
-*
-* Compute the growth in A' * x = b.
-*
- IF( UPPER ) THEN
- JFIRST = 1
- JLAST = N
- JINC = 1
- ELSE
- JFIRST = N
- JLAST = 1
- JINC = -1
- END IF
-*
- IF( TSCAL.NE.ONE ) THEN
- GROW = ZERO
- GO TO 80
- END IF
-*
- IF( NOUNIT ) THEN
-*
-* A is non-unit triangular.
-*
-* Compute GROW = 1/G(j) and XBND = 1/M(j).
-* Initially, M(0) = max{x(i), i=1,...,n}.
-*
- GROW = ONE / MAX( XBND, SMLNUM )
- XBND = GROW
- DO 60 J = JFIRST, JLAST, JINC
-*
-* Exit the loop if the growth factor is too small.
-*
- IF( GROW.LE.SMLNUM )
- $ GO TO 80
-*
-* G(j) = max( G(j-1), M(j-1)*( 1 + CNORM(j) ) )
-*
- XJ = ONE + CNORM( J )
- GROW = MIN( GROW, XBND / XJ )
-*
-* M(j) = M(j-1)*( 1 + CNORM(j) ) / abs(A(j,j))
-*
- TJJ = ABS( A( J, J ) )
- IF( XJ.GT.TJJ )
- $ XBND = XBND*( TJJ / XJ )
- 60 CONTINUE
- GROW = MIN( GROW, XBND )
- ELSE
-*
-* A is unit triangular.
-*
-* Compute GROW = 1/G(j), where G(0) = max{x(i), i=1,...,n}.
-*
- GROW = MIN( ONE, ONE / MAX( XBND, SMLNUM ) )
- DO 70 J = JFIRST, JLAST, JINC
-*
-* Exit the loop if the growth factor is too small.
-*
- IF( GROW.LE.SMLNUM )
- $ GO TO 80
-*
-* G(j) = ( 1 + CNORM(j) )*G(j-1)
-*
- XJ = ONE + CNORM( J )
- GROW = GROW / XJ
- 70 CONTINUE
- END IF
- 80 CONTINUE
- END IF
-*
- IF( ( GROW*TSCAL ).GT.SMLNUM ) THEN
-*
-* Use the Level 2 BLAS solve if the reciprocal of the bound on
-* elements of X is not too small.
-*
- CALL DTRSV( UPLO, TRANS, DIAG, N, A, LDA, X, 1 )
- ELSE
-*
-* Use a Level 1 BLAS solve, scaling intermediate results.
-*
- IF( XMAX.GT.BIGNUM ) THEN
-*
-* Scale X so that its components are less than or equal to
-* BIGNUM in absolute value.
-*
- SCALE = BIGNUM / XMAX
- CALL DSCAL( N, SCALE, X, 1 )
- XMAX = BIGNUM
- END IF
-*
- IF( NOTRAN ) THEN
-*
-* Solve A * x = b
-*
- DO 110 J = JFIRST, JLAST, JINC
-*
-* Compute x(j) = b(j) / A(j,j), scaling x if necessary.
-*
- XJ = ABS( X( J ) )
- IF( NOUNIT ) THEN
- TJJS = A( J, J )*TSCAL
- ELSE
- TJJS = TSCAL
- IF( TSCAL.EQ.ONE )
- $ GO TO 100
- END IF
- TJJ = ABS( TJJS )
- IF( TJJ.GT.SMLNUM ) THEN
-*
-* abs(A(j,j)) > SMLNUM:
-*
- IF( TJJ.LT.ONE ) THEN
- IF( XJ.GT.TJJ*BIGNUM ) THEN
-*
-* Scale x by 1/b(j).
-*
- REC = ONE / XJ
- CALL DSCAL( N, REC, X, 1 )
- SCALE = SCALE*REC
- XMAX = XMAX*REC
- END IF
- END IF
- X( J ) = X( J ) / TJJS
- XJ = ABS( X( J ) )
- ELSE IF( TJJ.GT.ZERO ) THEN
-*
-* 0 < abs(A(j,j)) <= SMLNUM:
-*
- IF( XJ.GT.TJJ*BIGNUM ) THEN
-*
-* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM
-* to avoid overflow when dividing by A(j,j).
-*
- REC = ( TJJ*BIGNUM ) / XJ
- IF( CNORM( J ).GT.ONE ) THEN
-*
-* Scale by 1/CNORM(j) to avoid overflow when
-* multiplying x(j) times column j.
-*
- REC = REC / CNORM( J )
- END IF
- CALL DSCAL( N, REC, X, 1 )
- SCALE = SCALE*REC
- XMAX = XMAX*REC
- END IF
- X( J ) = X( J ) / TJJS
- XJ = ABS( X( J ) )
- ELSE
-*
-* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and
-* scale = 0, and compute a solution to A*x = 0.
-*
- DO 90 I = 1, N
- X( I ) = ZERO
- 90 CONTINUE
- X( J ) = ONE
- XJ = ONE
- SCALE = ZERO
- XMAX = ZERO
- END IF
- 100 CONTINUE
-*
-* Scale x if necessary to avoid overflow when adding a
-* multiple of column j of A.
-*
- IF( XJ.GT.ONE ) THEN
- REC = ONE / XJ
- IF( CNORM( J ).GT.( BIGNUM-XMAX )*REC ) THEN
-*
-* Scale x by 1/(2*abs(x(j))).
-*
- REC = REC*HALF
- CALL DSCAL( N, REC, X, 1 )
- SCALE = SCALE*REC
- END IF
- ELSE IF( XJ*CNORM( J ).GT.( BIGNUM-XMAX ) ) THEN
-*
-* Scale x by 1/2.
-*
- CALL DSCAL( N, HALF, X, 1 )
- SCALE = SCALE*HALF
- END IF
-*
- IF( UPPER ) THEN
- IF( J.GT.1 ) THEN
-*
-* Compute the update
-* x(1:j-1) := x(1:j-1) - x(j) * A(1:j-1,j)
-*
- CALL DAXPY( J-1, -X( J )*TSCAL, A( 1, J ), 1, X,
- $ 1 )
- I = IDAMAX( J-1, X, 1 )
- XMAX = ABS( X( I ) )
- END IF
- ELSE
- IF( J.LT.N ) THEN
-*
-* Compute the update
-* x(j+1:n) := x(j+1:n) - x(j) * A(j+1:n,j)
-*
- CALL DAXPY( N-J, -X( J )*TSCAL, A( J+1, J ), 1,
- $ X( J+1 ), 1 )
- I = J + IDAMAX( N-J, X( J+1 ), 1 )
- XMAX = ABS( X( I ) )
- END IF
- END IF
- 110 CONTINUE
-*
- ELSE
-*
-* Solve A' * x = b
-*
- DO 160 J = JFIRST, JLAST, JINC
-*
-* Compute x(j) = b(j) - sum A(k,j)*x(k).
-* k<>j
-*
- XJ = ABS( X( J ) )
- USCAL = TSCAL
- REC = ONE / MAX( XMAX, ONE )
- IF( CNORM( J ).GT.( BIGNUM-XJ )*REC ) THEN
-*
-* If x(j) could overflow, scale x by 1/(2*XMAX).
-*
- REC = REC*HALF
- IF( NOUNIT ) THEN
- TJJS = A( J, J )*TSCAL
- ELSE
- TJJS = TSCAL
- END IF
- TJJ = ABS( TJJS )
- IF( TJJ.GT.ONE ) THEN
-*
-* Divide by A(j,j) when scaling x if A(j,j) > 1.
-*
- REC = MIN( ONE, REC*TJJ )
- USCAL = USCAL / TJJS
- END IF
- IF( REC.LT.ONE ) THEN
- CALL DSCAL( N, REC, X, 1 )
- SCALE = SCALE*REC
- XMAX = XMAX*REC
- END IF
- END IF
-*
- SUMJ = ZERO
- IF( USCAL.EQ.ONE ) THEN
-*
-* If the scaling needed for A in the dot product is 1,
-* call DDOT to perform the dot product.
-*
- IF( UPPER ) THEN
- SUMJ = DDOT( J-1, A( 1, J ), 1, X, 1 )
- ELSE IF( J.LT.N ) THEN
- SUMJ = DDOT( N-J, A( J+1, J ), 1, X( J+1 ), 1 )
- END IF
- ELSE
-*
-* Otherwise, use in-line code for the dot product.
-*
- IF( UPPER ) THEN
- DO 120 I = 1, J - 1
- SUMJ = SUMJ + ( A( I, J )*USCAL )*X( I )
- 120 CONTINUE
- ELSE IF( J.LT.N ) THEN
- DO 130 I = J + 1, N
- SUMJ = SUMJ + ( A( I, J )*USCAL )*X( I )
- 130 CONTINUE
- END IF
- END IF
-*
- IF( USCAL.EQ.TSCAL ) THEN
-*
-* Compute x(j) := ( x(j) - sumj ) / A(j,j) if 1/A(j,j)
-* was not used to scale the dotproduct.
-*
- X( J ) = X( J ) - SUMJ
- XJ = ABS( X( J ) )
- IF( NOUNIT ) THEN
- TJJS = A( J, J )*TSCAL
- ELSE
- TJJS = TSCAL
- IF( TSCAL.EQ.ONE )
- $ GO TO 150
- END IF
-*
-* Compute x(j) = x(j) / A(j,j), scaling if necessary.
-*
- TJJ = ABS( TJJS )
- IF( TJJ.GT.SMLNUM ) THEN
-*
-* abs(A(j,j)) > SMLNUM:
-*
- IF( TJJ.LT.ONE ) THEN
- IF( XJ.GT.TJJ*BIGNUM ) THEN
-*
-* Scale X by 1/abs(x(j)).
-*
- REC = ONE / XJ
- CALL DSCAL( N, REC, X, 1 )
- SCALE = SCALE*REC
- XMAX = XMAX*REC
- END IF
- END IF
- X( J ) = X( J ) / TJJS
- ELSE IF( TJJ.GT.ZERO ) THEN
-*
-* 0 < abs(A(j,j)) <= SMLNUM:
-*
- IF( XJ.GT.TJJ*BIGNUM ) THEN
-*
-* Scale x by (1/abs(x(j)))*abs(A(j,j))*BIGNUM.
-*
- REC = ( TJJ*BIGNUM ) / XJ
- CALL DSCAL( N, REC, X, 1 )
- SCALE = SCALE*REC
- XMAX = XMAX*REC
- END IF
- X( J ) = X( J ) / TJJS
- ELSE
-*
-* A(j,j) = 0: Set x(1:n) = 0, x(j) = 1, and
-* scale = 0, and compute a solution to A'*x = 0.
-*
- DO 140 I = 1, N
- X( I ) = ZERO
- 140 CONTINUE
- X( J ) = ONE
- SCALE = ZERO
- XMAX = ZERO
- END IF
- 150 CONTINUE
- ELSE
-*
-* Compute x(j) := x(j) / A(j,j) - sumj if the dot
-* product has already been divided by 1/A(j,j).
-*
- X( J ) = X( J ) / TJJS - SUMJ
- END IF
- XMAX = MAX( XMAX, ABS( X( J ) ) )
- 160 CONTINUE
- END IF
- SCALE = SCALE / TSCAL
- END IF
-*
-* Scale the column norms by 1/TSCAL for return.
-*
- IF( TSCAL.NE.ONE ) THEN
- CALL DSCAL( N, ONE / TSCAL, CNORM, 1 )
- END IF
-*
- RETURN
-*
-* End of DLATRS
-*
- END