--- rpl/lapack/lapack/dgebal.f 2010/08/07 13:18:06 1.5 +++ rpl/lapack/lapack/dgebal.f 2023/08/07 08:38:47 1.21 @@ -1,9 +1,166 @@ +*> \brief \b DGEBAL +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download DGEBAL + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> +*> [TXT] +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE DGEBAL( JOB, N, A, LDA, ILO, IHI, SCALE, INFO ) +* +* .. Scalar Arguments .. +* CHARACTER JOB +* INTEGER IHI, ILO, INFO, LDA, N +* .. +* .. Array Arguments .. +* DOUBLE PRECISION A( LDA, * ), SCALE( * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> DGEBAL balances a general real matrix A. This involves, first, +*> permuting A by a similarity transformation to isolate eigenvalues +*> in the first 1 to ILO-1 and last IHI+1 to N elements on the +*> diagonal; and second, applying a diagonal similarity transformation +*> to rows and columns ILO to IHI to make the rows and columns as +*> close in norm as possible. Both steps are optional. +*> +*> Balancing may reduce the 1-norm of the matrix, and improve the +*> accuracy of the computed eigenvalues and/or eigenvectors. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] JOB +*> \verbatim +*> JOB is CHARACTER*1 +*> Specifies the operations to be performed on A: +*> = 'N': none: simply set ILO = 1, IHI = N, SCALE(I) = 1.0 +*> for i = 1,...,N; +*> = 'P': permute only; +*> = 'S': scale only; +*> = 'B': both permute and scale. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The order of the matrix A. N >= 0. +*> \endverbatim +*> +*> \param[in,out] A +*> \verbatim +*> A is DOUBLE PRECISION array, dimension (LDA,N) +*> On entry, the input matrix A. +*> On exit, A is overwritten by the balanced matrix. +*> If JOB = 'N', A is not referenced. +*> See Further Details. +*> \endverbatim +*> +*> \param[in] LDA +*> \verbatim +*> LDA is INTEGER +*> The leading dimension of the array A. LDA >= max(1,N). +*> \endverbatim +*> +*> \param[out] ILO +*> \verbatim +*> ILO is INTEGER +*> \endverbatim +*> \param[out] IHI +*> \verbatim +*> IHI is INTEGER +*> ILO and IHI are set to integers such that on exit +*> A(i,j) = 0 if i > j and j = 1,...,ILO-1 or I = IHI+1,...,N. +*> If JOB = 'N' or 'S', ILO = 1 and IHI = N. +*> \endverbatim +*> +*> \param[out] SCALE +*> \verbatim +*> SCALE is DOUBLE PRECISION array, dimension (N) +*> Details of the permutations and scaling factors applied to +*> A. If P(j) is the index of the row and column interchanged +*> with row and column j and D(j) is the scaling factor +*> applied to row and column j, then +*> SCALE(j) = P(j) for j = 1,...,ILO-1 +*> = D(j) for j = ILO,...,IHI +*> = P(j) for j = IHI+1,...,N. +*> The order in which the interchanges are made is N to IHI+1, +*> then 1 to ILO-1. +*> \endverbatim +*> +*> \param[out] INFO +*> \verbatim +*> INFO is INTEGER +*> = 0: successful exit. +*> < 0: if INFO = -i, the i-th argument had an illegal value. +*> \endverbatim +* +* Authors: +* ======== +* +*> \author Univ. of Tennessee +*> \author Univ. of California Berkeley +*> \author Univ. of Colorado Denver +*> \author NAG Ltd. +* +*> \ingroup doubleGEcomputational +* +*> \par Further Details: +* ===================== +*> +*> \verbatim +*> +*> The permutations consist of row and column interchanges which put +*> the matrix in the form +*> +*> ( T1 X Y ) +*> P A P = ( 0 B Z ) +*> ( 0 0 T2 ) +*> +*> where T1 and T2 are upper triangular matrices whose eigenvalues lie +*> along the diagonal. The column indices ILO and IHI mark the starting +*> and ending columns of the submatrix B. Balancing consists of applying +*> a diagonal similarity transformation inv(D) * B * D to make the +*> 1-norms of each row of B and its corresponding column nearly equal. +*> The output matrix is +*> +*> ( T1 X*D Y ) +*> ( 0 inv(D)*B*D inv(D)*Z ). +*> ( 0 0 T2 ) +*> +*> Information about the permutations P and the diagonal matrix D is +*> returned in the vector SCALE. +*> +*> This subroutine is based on the EISPACK routine BALANC. +*> +*> Modified by Tzu-Yi Chen, Computer Science Division, University of +*> California at Berkeley, USA +*> \endverbatim +*> +* ===================================================================== SUBROUTINE DGEBAL( JOB, N, A, LDA, ILO, IHI, SCALE, INFO ) * -* -- LAPACK routine (version 3.2.2) -- +* -- LAPACK computational routine -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* June 2010 * * .. Scalar Arguments .. CHARACTER JOB @@ -13,92 +170,6 @@ DOUBLE PRECISION A( LDA, * ), SCALE( * ) * .. * -* Purpose -* ======= -* -* DGEBAL balances a general real matrix A. This involves, first, -* permuting A by a similarity transformation to isolate eigenvalues -* in the first 1 to ILO-1 and last IHI+1 to N elements on the -* diagonal; and second, applying a diagonal similarity transformation -* to rows and columns ILO to IHI to make the rows and columns as -* close in norm as possible. Both steps are optional. -* -* Balancing may reduce the 1-norm of the matrix, and improve the -* accuracy of the computed eigenvalues and/or eigenvectors. -* -* Arguments -* ========= -* -* JOB (input) CHARACTER*1 -* Specifies the operations to be performed on A: -* = 'N': none: simply set ILO = 1, IHI = N, SCALE(I) = 1.0 -* for i = 1,...,N; -* = 'P': permute only; -* = 'S': scale only; -* = 'B': both permute and scale. -* -* N (input) INTEGER -* The order of the matrix A. N >= 0. -* -* A (input/output) DOUBLE PRECISION array, dimension (LDA,N) -* On entry, the input matrix A. -* On exit, A is overwritten by the balanced matrix. -* If JOB = 'N', A is not referenced. -* See Further Details. -* -* LDA (input) INTEGER -* The leading dimension of the array A. LDA >= max(1,N). -* -* ILO (output) INTEGER -* IHI (output) INTEGER -* ILO and IHI are set to integers such that on exit -* A(i,j) = 0 if i > j and j = 1,...,ILO-1 or I = IHI+1,...,N. -* If JOB = 'N' or 'S', ILO = 1 and IHI = N. -* -* SCALE (output) DOUBLE PRECISION array, dimension (N) -* Details of the permutations and scaling factors applied to -* A. If P(j) is the index of the row and column interchanged -* with row and column j and D(j) is the scaling factor -* applied to row and column j, then -* SCALE(j) = P(j) for j = 1,...,ILO-1 -* = D(j) for j = ILO,...,IHI -* = P(j) for j = IHI+1,...,N. -* The order in which the interchanges are made is N to IHI+1, -* then 1 to ILO-1. -* -* INFO (output) INTEGER -* = 0: successful exit. -* < 0: if INFO = -i, the i-th argument had an illegal value. -* -* Further Details -* =============== -* -* The permutations consist of row and column interchanges which put -* the matrix in the form -* -* ( T1 X Y ) -* P A P = ( 0 B Z ) -* ( 0 0 T2 ) -* -* where T1 and T2 are upper triangular matrices whose eigenvalues lie -* along the diagonal. The column indices ILO and IHI mark the starting -* and ending columns of the submatrix B. Balancing consists of applying -* a diagonal similarity transformation inv(D) * B * D to make the -* 1-norms of each row of B and its corresponding column nearly equal. -* The output matrix is -* -* ( T1 X*D Y ) -* ( 0 inv(D)*B*D inv(D)*Z ). -* ( 0 0 T2 ) -* -* Information about the permutations P and the diagonal matrix D is -* returned in the vector SCALE. -* -* This subroutine is based on the EISPACK routine BALANC. -* -* Modified by Tzu-Yi Chen, Computer Science Division, University of -* California at Berkeley, USA -* * ===================================================================== * * .. Parameters .. @@ -118,8 +189,8 @@ * .. External Functions .. LOGICAL DISNAN, LSAME INTEGER IDAMAX - DOUBLE PRECISION DLAMCH - EXTERNAL DISNAN, LSAME, IDAMAX, DLAMCH + DOUBLE PRECISION DLAMCH, DNRM2 + EXTERNAL DISNAN, LSAME, IDAMAX, DLAMCH, DNRM2 * .. * .. External Subroutines .. EXTERNAL DSCAL, DSWAP, XERBLA @@ -127,8 +198,6 @@ * .. Intrinsic Functions .. INTRINSIC ABS, MAX, MIN * .. -* .. Executable Statements .. -* * Test the input parameters * INFO = 0 @@ -238,19 +307,14 @@ SFMAX1 = ONE / SFMIN1 SFMIN2 = SFMIN1*SCLFAC SFMAX2 = ONE / SFMIN2 +* 140 CONTINUE NOCONV = .FALSE. * DO 200 I = K, L - C = ZERO - R = ZERO * - DO 150 J = K, L - IF( J.EQ.I ) - $ GO TO 150 - C = C + ABS( A( J, I ) ) - R = R + ABS( A( I, J ) ) - 150 CONTINUE + C = DNRM2( L-K+1, A( K, I ), 1 ) + R = DNRM2( L-K+1, A( I, K ), LDA ) ICA = IDAMAX( L, A( 1, I ), 1 ) CA = ABS( A( ICA, I ) ) IRA = IDAMAX( N-K+1, A( I, K ), LDA )