diff --git a/lapack-netlib/SRC/cbdsqr.f b/lapack-netlib/SRC/cbdsqr.f index 40706644ee..cf1459ad22 100644 --- a/lapack-netlib/SRC/cbdsqr.f +++ b/lapack-netlib/SRC/cbdsqr.f @@ -204,6 +204,17 @@ *> algorithm through its inner loop. The algorithms stops *> (and so fails to converge) if the number of passes *> through the inner loop exceeds MAXITR*N**2. +*> +*> \endverbatim +* +*> \par Note: +* =========== +*> +*> \verbatim +*> Bug report from Cezary Dendek. +*> On November 3rd 2023, the INTEGER variable MAXIT = MAXITR*N**2 is +*> removed since it can overflow pretty easily (for N larger or equal +*> than 18,919). We instead use MAXITDIVN = MAXITR*N. *> \endverbatim * * Authors: @@ -214,7 +225,7 @@ *> \author Univ. of Colorado Denver *> \author NAG Ltd. * -*> \ingroup complexOTHERcomputational +*> \ingroup bdsqr * * ===================================================================== SUBROUTINE CBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, @@ -255,8 +266,8 @@ SUBROUTINE CBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, * .. * .. Local Scalars .. LOGICAL LOWER, ROTATE - INTEGER I, IDIR, ISUB, ITER, J, LL, LLL, M, MAXIT, NM1, - $ NM12, NM13, OLDLL, OLDM + INTEGER I, IDIR, ISUB, ITER, ITERDIVN, J, LL, LLL, M, + $ MAXITDIVN, NM1, NM12, NM13, OLDLL, OLDM REAL ABSE, ABSS, COSL, COSR, CS, EPS, F, G, H, MU, $ OLDCS, OLDSN, R, SHIFT, SIGMN, SIGMX, SINL, $ SINR, SLL, SMAX, SMIN, SMINOA, @@ -389,20 +400,21 @@ SUBROUTINE CBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, 40 CONTINUE 50 CONTINUE SMINOA = SMINOA / SQRT( REAL( N ) ) - THRESH = MAX( TOL*SMINOA, MAXITR*N*N*UNFL ) + THRESH = MAX( TOL*SMINOA, MAXITR*(N*(N*UNFL)) ) ELSE * * Absolute accuracy desired * - THRESH = MAX( ABS( TOL )*SMAX, MAXITR*N*N*UNFL ) + THRESH = MAX( ABS( TOL )*SMAX, MAXITR*(N*(N*UNFL)) ) END IF * * Prepare for main iteration loop for the singular values * (MAXIT is the maximum number of passes through the inner * loop permitted before nonconvergence signalled.) * - MAXIT = MAXITR*N*N - ITER = 0 + MAXITDIVN = MAXITR*N + ITERDIVN = 0 + ITER = -1 OLDLL = -1 OLDM = -1 * @@ -418,8 +430,12 @@ SUBROUTINE CBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, * IF( M.LE.1 ) $ GO TO 160 - IF( ITER.GT.MAXIT ) - $ GO TO 200 + IF( ITER.GE.N ) THEN + ITER = ITER - N + ITERDIVN = ITERDIVN + 1 + IF( ITERDIVN.GE.MAXITDIVN ) + $ GO TO 200 + END IF * * Find diagonal block of matrix to work on * diff --git a/lapack-netlib/SRC/zbdsqr.f b/lapack-netlib/SRC/zbdsqr.f index faedafc3ca..865bb9dd59 100644 --- a/lapack-netlib/SRC/zbdsqr.f +++ b/lapack-netlib/SRC/zbdsqr.f @@ -204,6 +204,17 @@ *> algorithm through its inner loop. The algorithms stops *> (and so fails to converge) if the number of passes *> through the inner loop exceeds MAXITR*N**2. +*> +*> \endverbatim +* +*> \par Note: +* =========== +*> +*> \verbatim +*> Bug report from Cezary Dendek. +*> On November 3rd 2023, the INTEGER variable MAXIT = MAXITR*N**2 is +*> removed since it can overflow pretty easily (for N larger or equal +*> than 18,919). We instead use MAXITDIVN = MAXITR*N. *> \endverbatim * * Authors: @@ -214,7 +225,7 @@ *> \author Univ. of Colorado Denver *> \author NAG Ltd. * -*> \ingroup complex16OTHERcomputational +*> \ingroup bdsqr * * ===================================================================== SUBROUTINE ZBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, @@ -255,8 +266,8 @@ SUBROUTINE ZBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, * .. * .. Local Scalars .. LOGICAL LOWER, ROTATE - INTEGER I, IDIR, ISUB, ITER, J, LL, LLL, M, MAXIT, NM1, - $ NM12, NM13, OLDLL, OLDM + INTEGER I, IDIR, ISUB, ITER, ITERDIVN, J, LL, LLL, M, + $ MAXITDIVN, NM1, NM12, NM13, OLDLL, OLDM DOUBLE PRECISION ABSE, ABSS, COSL, COSR, CS, EPS, F, G, H, MU, $ OLDCS, OLDSN, R, SHIFT, SIGMN, SIGMX, SINL, $ SINR, SLL, SMAX, SMIN, SMINOA, @@ -389,20 +400,21 @@ SUBROUTINE ZBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, 40 CONTINUE 50 CONTINUE SMINOA = SMINOA / SQRT( DBLE( N ) ) - THRESH = MAX( TOL*SMINOA, MAXITR*N*N*UNFL ) + THRESH = MAX( TOL*SMINOA, MAXITR*(N*(N*UNFL)) ) ELSE * * Absolute accuracy desired * - THRESH = MAX( ABS( TOL )*SMAX, MAXITR*N*N*UNFL ) + THRESH = MAX( ABS( TOL )*SMAX, MAXITR*(N*(N*UNFL)) ) END IF * * Prepare for main iteration loop for the singular values * (MAXIT is the maximum number of passes through the inner * loop permitted before nonconvergence signalled.) * - MAXIT = MAXITR*N*N - ITER = 0 + MAXITDIVN = MAXITR*N + ITERDIVN = 0 + ITER = -1 OLDLL = -1 OLDM = -1 * @@ -418,8 +430,12 @@ SUBROUTINE ZBDSQR( UPLO, N, NCVT, NRU, NCC, D, E, VT, LDVT, U, * IF( M.LE.1 ) $ GO TO 160 - IF( ITER.GT.MAXIT ) - $ GO TO 200 + IF( ITER.GE.N ) THEN + ITER = ITER - N + ITERDIVN = ITERDIVN + 1 + IF( ITERDIVN.GE.MAXITDIVN ) + $ GO TO 200 + END IF * * Find diagonal block of matrix to work on *