--- rpl/lapack/lapack/zgeql2.f 2010/08/06 15:28:52 1.3 +++ rpl/lapack/lapack/zgeql2.f 2023/08/07 08:39:18 1.20 @@ -1,9 +1,129 @@ +*> \brief \b ZGEQL2 computes the QL factorization of a general rectangular matrix using an unblocked algorithm. +* +* =========== DOCUMENTATION =========== +* +* Online html documentation available at +* http://www.netlib.org/lapack/explore-html/ +* +*> \htmlonly +*> Download ZGEQL2 + dependencies +*> +*> [TGZ] +*> +*> [ZIP] +*> +*> [TXT] +*> \endhtmlonly +* +* Definition: +* =========== +* +* SUBROUTINE ZGEQL2( M, N, A, LDA, TAU, WORK, INFO ) +* +* .. Scalar Arguments .. +* INTEGER INFO, LDA, M, N +* .. +* .. Array Arguments .. +* COMPLEX*16 A( LDA, * ), TAU( * ), WORK( * ) +* .. +* +* +*> \par Purpose: +* ============= +*> +*> \verbatim +*> +*> ZGEQL2 computes a QL factorization of a complex m by n matrix A: +*> A = Q * L. +*> \endverbatim +* +* Arguments: +* ========== +* +*> \param[in] M +*> \verbatim +*> M is INTEGER +*> The number of rows of the matrix A. M >= 0. +*> \endverbatim +*> +*> \param[in] N +*> \verbatim +*> N is INTEGER +*> The number of columns of the matrix A. N >= 0. +*> \endverbatim +*> +*> \param[in,out] A +*> \verbatim +*> A is COMPLEX*16 array, dimension (LDA,N) +*> On entry, the m by n matrix A. +*> On exit, if m >= n, the lower triangle of the subarray +*> A(m-n+1:m,1:n) contains the n by n lower triangular matrix L; +*> if m <= n, the elements on and below the (n-m)-th +*> superdiagonal contain the m by n lower trapezoidal matrix L; +*> the remaining elements, with the array TAU, represent the +*> unitary matrix Q as a product of elementary reflectors +*> (see Further Details). +*> \endverbatim +*> +*> \param[in] LDA +*> \verbatim +*> LDA is INTEGER +*> The leading dimension of the array A. LDA >= max(1,M). +*> \endverbatim +*> +*> \param[out] TAU +*> \verbatim +*> TAU is COMPLEX*16 array, dimension (min(M,N)) +*> The scalar factors of the elementary reflectors (see Further +*> Details). +*> \endverbatim +*> +*> \param[out] WORK +*> \verbatim +*> WORK is COMPLEX*16 array, dimension (N) +*> \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 complex16GEcomputational +* +*> \par Further Details: +* ===================== +*> +*> \verbatim +*> +*> The matrix Q is represented as a product of elementary reflectors +*> +*> Q = H(k) . . . H(2) H(1), where k = min(m,n). +*> +*> Each H(i) has the form +*> +*> H(i) = I - tau * v * v**H +*> +*> where tau is a complex scalar, and v is a complex vector with +*> v(m-k+i+1:m) = 0 and v(m-k+i) = 1; v(1:m-k+i-1) is stored on exit in +*> A(1:m-k+i-1,n-k+i), and tau in TAU(i). +*> \endverbatim +*> +* ===================================================================== SUBROUTINE ZGEQL2( M, N, A, LDA, TAU, WORK, INFO ) * -* -- LAPACK routine (version 3.2) -- +* -- LAPACK computational routine -- * -- LAPACK is a software package provided by Univ. of Tennessee, -- * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- -* November 2006 * * .. Scalar Arguments .. INTEGER INFO, LDA, M, N @@ -12,59 +132,6 @@ COMPLEX*16 A( LDA, * ), TAU( * ), WORK( * ) * .. * -* Purpose -* ======= -* -* ZGEQL2 computes a QL factorization of a complex m by n matrix A: -* A = Q * L. -* -* Arguments -* ========= -* -* M (input) INTEGER -* The number of rows of the matrix A. M >= 0. -* -* N (input) INTEGER -* The number of columns of the matrix A. N >= 0. -* -* A (input/output) COMPLEX*16 array, dimension (LDA,N) -* On entry, the m by n matrix A. -* On exit, if m >= n, the lower triangle of the subarray -* A(m-n+1:m,1:n) contains the n by n lower triangular matrix L; -* if m <= n, the elements on and below the (n-m)-th -* superdiagonal contain the m by n lower trapezoidal matrix L; -* the remaining elements, with the array TAU, represent the -* unitary matrix Q as a product of elementary reflectors -* (see Further Details). -* -* LDA (input) INTEGER -* The leading dimension of the array A. LDA >= max(1,M). -* -* TAU (output) COMPLEX*16 array, dimension (min(M,N)) -* The scalar factors of the elementary reflectors (see Further -* Details). -* -* WORK (workspace) COMPLEX*16 array, dimension (N) -* -* INFO (output) INTEGER -* = 0: successful exit -* < 0: if INFO = -i, the i-th argument had an illegal value -* -* Further Details -* =============== -* -* The matrix Q is represented as a product of elementary reflectors -* -* Q = H(k) . . . H(2) H(1), where k = min(m,n). -* -* Each H(i) has the form -* -* H(i) = I - tau * v * v' -* -* where tau is a complex scalar, and v is a complex vector with -* v(m-k+i+1:m) = 0 and v(m-k+i) = 1; v(1:m-k+i-1) is stored on exit in -* A(1:m-k+i-1,n-k+i), and tau in TAU(i). -* * ===================================================================== * * .. Parameters .. @@ -76,7 +143,7 @@ COMPLEX*16 ALPHA * .. * .. External Subroutines .. - EXTERNAL XERBLA, ZLARF, ZLARFP + EXTERNAL XERBLA, ZLARF, ZLARFG * .. * .. Intrinsic Functions .. INTRINSIC DCONJG, MAX, MIN @@ -106,9 +173,9 @@ * A(1:m-k+i-1,n-k+i) * ALPHA = A( M-K+I, N-K+I ) - CALL ZLARFP( M-K+I, ALPHA, A( 1, N-K+I ), 1, TAU( I ) ) + CALL ZLARFG( M-K+I, ALPHA, A( 1, N-K+I ), 1, TAU( I ) ) * -* Apply H(i)' to A(1:m-k+i,1:n-k+i-1) from the left +* Apply H(i)**H to A(1:m-k+i,1:n-k+i-1) from the left * A( M-K+I, N-K+I ) = ONE CALL ZLARF( 'Left', M-K+I, N-K+I-1, A( 1, N-K+I ), 1,