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763 lines
22 KiB
763 lines
22 KiB
*> \brief \b SLARFB |
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* |
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* =========== DOCUMENTATION =========== |
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* |
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* Online html documentation available at |
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* http://www.netlib.org/lapack/explore-html/ |
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* |
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*> \htmlonly |
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*> Download SLARFB + dependencies |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarfb.f"> |
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*> [TGZ]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarfb.f"> |
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*> [ZIP]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarfb.f"> |
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*> [TXT]</a> |
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*> \endhtmlonly |
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* |
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* Definition: |
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* =========== |
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* |
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* SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV, |
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* T, LDT, C, LDC, WORK, LDWORK ) |
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* |
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* .. Scalar Arguments .. |
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* CHARACTER DIRECT, SIDE, STOREV, TRANS |
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* INTEGER K, LDC, LDT, LDV, LDWORK, M, N |
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* .. |
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* .. Array Arguments .. |
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* REAL C( LDC, * ), T( LDT, * ), V( LDV, * ), |
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* $ WORK( LDWORK, * ) |
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* .. |
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* |
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* |
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*> \par Purpose: |
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* ============= |
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*> |
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*> \verbatim |
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*> |
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*> SLARFB applies a real block reflector H or its transpose H**T to a |
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*> real m by n matrix C, from either the left or the right. |
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*> \endverbatim |
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* |
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* Arguments: |
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* ========== |
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* |
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*> \param[in] SIDE |
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*> \verbatim |
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*> SIDE is CHARACTER*1 |
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*> = 'L': apply H or H**T from the Left |
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*> = 'R': apply H or H**T from the Right |
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*> \endverbatim |
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*> |
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*> \param[in] TRANS |
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*> \verbatim |
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*> TRANS is CHARACTER*1 |
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*> = 'N': apply H (No transpose) |
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*> = 'T': apply H**T (Transpose) |
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*> \endverbatim |
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*> |
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*> \param[in] DIRECT |
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*> \verbatim |
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*> DIRECT is CHARACTER*1 |
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*> Indicates how H is formed from a product of elementary |
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*> reflectors |
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*> = 'F': H = H(1) H(2) . . . H(k) (Forward) |
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*> = 'B': H = H(k) . . . H(2) H(1) (Backward) |
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*> \endverbatim |
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*> |
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*> \param[in] STOREV |
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*> \verbatim |
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*> STOREV is CHARACTER*1 |
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*> Indicates how the vectors which define the elementary |
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*> reflectors are stored: |
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*> = 'C': Columnwise |
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*> = 'R': Rowwise |
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*> \endverbatim |
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*> |
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*> \param[in] M |
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*> \verbatim |
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*> M is INTEGER |
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*> The number of rows of the matrix C. |
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*> \endverbatim |
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*> |
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*> \param[in] N |
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*> \verbatim |
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*> N is INTEGER |
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*> The number of columns of the matrix C. |
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*> \endverbatim |
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*> |
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*> \param[in] K |
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*> \verbatim |
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*> K is INTEGER |
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*> The order of the matrix T (= the number of elementary |
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*> reflectors whose product defines the block reflector). |
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*> \endverbatim |
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*> |
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*> \param[in] V |
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*> \verbatim |
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*> V is REAL array, dimension |
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*> (LDV,K) if STOREV = 'C' |
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*> (LDV,M) if STOREV = 'R' and SIDE = 'L' |
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*> (LDV,N) if STOREV = 'R' and SIDE = 'R' |
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*> The matrix V. See Further Details. |
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*> \endverbatim |
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*> |
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*> \param[in] LDV |
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*> \verbatim |
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*> LDV is INTEGER |
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*> The leading dimension of the array V. |
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*> If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M); |
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*> if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N); |
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*> if STOREV = 'R', LDV >= K. |
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*> \endverbatim |
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*> |
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*> \param[in] T |
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*> \verbatim |
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*> T is REAL array, dimension (LDT,K) |
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*> The triangular k by k matrix T in the representation of the |
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*> block reflector. |
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*> \endverbatim |
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*> |
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*> \param[in] LDT |
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*> \verbatim |
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*> LDT is INTEGER |
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*> The leading dimension of the array T. LDT >= K. |
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*> \endverbatim |
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*> |
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*> \param[in,out] C |
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*> \verbatim |
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*> C is REAL array, dimension (LDC,N) |
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*> On entry, the m by n matrix C. |
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*> On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T. |
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*> \endverbatim |
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*> |
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*> \param[in] LDC |
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*> \verbatim |
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*> LDC is INTEGER |
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*> The leading dimension of the array C. LDC >= max(1,M). |
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*> \endverbatim |
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*> |
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*> \param[out] WORK |
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*> \verbatim |
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*> WORK is REAL array, dimension (LDWORK,K) |
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*> \endverbatim |
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*> |
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*> \param[in] LDWORK |
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*> \verbatim |
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*> LDWORK is INTEGER |
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*> The leading dimension of the array WORK. |
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*> If SIDE = 'L', LDWORK >= max(1,N); |
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*> if SIDE = 'R', LDWORK >= max(1,M). |
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*> \endverbatim |
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* |
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* Authors: |
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* ======== |
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* |
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*> \author Univ. of Tennessee |
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*> \author Univ. of California Berkeley |
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*> \author Univ. of Colorado Denver |
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*> \author NAG Ltd. |
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* |
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*> \date November 2011 |
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* |
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*> \ingroup realOTHERauxiliary |
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* |
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*> \par Further Details: |
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* ===================== |
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*> |
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*> \verbatim |
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*> |
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*> The shape of the matrix V and the storage of the vectors which define |
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*> the H(i) is best illustrated by the following example with n = 5 and |
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*> k = 3. The elements equal to 1 are not stored; the corresponding |
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*> array elements are modified but restored on exit. The rest of the |
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*> array is not used. |
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*> |
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*> DIRECT = 'F' and STOREV = 'C': DIRECT = 'F' and STOREV = 'R': |
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*> |
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*> V = ( 1 ) V = ( 1 v1 v1 v1 v1 ) |
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*> ( v1 1 ) ( 1 v2 v2 v2 ) |
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*> ( v1 v2 1 ) ( 1 v3 v3 ) |
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*> ( v1 v2 v3 ) |
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*> ( v1 v2 v3 ) |
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*> |
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*> DIRECT = 'B' and STOREV = 'C': DIRECT = 'B' and STOREV = 'R': |
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*> |
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*> V = ( v1 v2 v3 ) V = ( v1 v1 1 ) |
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*> ( v1 v2 v3 ) ( v2 v2 v2 1 ) |
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*> ( 1 v2 v3 ) ( v3 v3 v3 v3 1 ) |
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*> ( 1 v3 ) |
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*> ( 1 ) |
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*> \endverbatim |
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*> |
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* ===================================================================== |
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SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV, |
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$ T, LDT, C, LDC, WORK, LDWORK ) |
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* |
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* -- LAPACK auxiliary routine (version 3.4.0) -- |
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* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
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* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
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* November 2011 |
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* |
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* .. Scalar Arguments .. |
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CHARACTER DIRECT, SIDE, STOREV, TRANS |
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INTEGER K, LDC, LDT, LDV, LDWORK, M, N |
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* .. |
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* .. Array Arguments .. |
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REAL C( LDC, * ), T( LDT, * ), V( LDV, * ), |
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$ WORK( LDWORK, * ) |
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* .. |
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* |
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* ===================================================================== |
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* |
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* .. Parameters .. |
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REAL ONE |
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PARAMETER ( ONE = 1.0E+0 ) |
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* .. |
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* .. Local Scalars .. |
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CHARACTER TRANST |
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INTEGER I, J, LASTV, LASTC |
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* .. |
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* .. External Functions .. |
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LOGICAL LSAME |
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INTEGER ILASLR, ILASLC |
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EXTERNAL LSAME, ILASLR, ILASLC |
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* .. |
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* .. External Subroutines .. |
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EXTERNAL SCOPY, SGEMM, STRMM |
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* .. |
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* .. Executable Statements .. |
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* |
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* Quick return if possible |
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* |
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IF( M.LE.0 .OR. N.LE.0 ) |
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$ RETURN |
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* |
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IF( LSAME( TRANS, 'N' ) ) THEN |
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TRANST = 'T' |
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ELSE |
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TRANST = 'N' |
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END IF |
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* |
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IF( LSAME( STOREV, 'C' ) ) THEN |
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* |
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IF( LSAME( DIRECT, 'F' ) ) THEN |
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* |
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* Let V = ( V1 ) (first K rows) |
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* ( V2 ) |
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* where V1 is unit lower triangular. |
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* |
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IF( LSAME( SIDE, 'L' ) ) THEN |
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* |
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* Form H * C or H**T * C where C = ( C1 ) |
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* ( C2 ) |
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* |
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LASTV = MAX( K, ILASLR( M, K, V, LDV ) ) |
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LASTC = ILASLC( LASTV, N, C, LDC ) |
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* |
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* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK) |
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* |
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* W := C1**T |
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* |
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DO 10 J = 1, K |
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CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 ) |
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10 CONTINUE |
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* |
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* W := W * V1 |
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* |
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CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
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$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
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IF( LASTV.GT.K ) THEN |
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* |
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* W := W + C2**T *V2 |
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* |
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CALL SGEMM( 'Transpose', 'No transpose', |
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$ LASTC, K, LASTV-K, |
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$ ONE, C( K+1, 1 ), LDC, V( K+1, 1 ), LDV, |
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$ ONE, WORK, LDWORK ) |
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END IF |
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* |
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* W := W * T**T or W * T |
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* |
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CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit', |
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$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
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* |
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* C := C - V * W**T |
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* |
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IF( LASTV.GT.K ) THEN |
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* |
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* C2 := C2 - V2 * W**T |
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* |
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CALL SGEMM( 'No transpose', 'Transpose', |
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$ LASTV-K, LASTC, K, |
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$ -ONE, V( K+1, 1 ), LDV, WORK, LDWORK, ONE, |
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$ C( K+1, 1 ), LDC ) |
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END IF |
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* |
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* W := W * V1**T |
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* |
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CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit', |
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$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
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* |
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* C1 := C1 - W**T |
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* |
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DO 30 J = 1, K |
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DO 20 I = 1, LASTC |
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C( J, I ) = C( J, I ) - WORK( I, J ) |
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20 CONTINUE |
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30 CONTINUE |
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* |
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ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
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* |
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* Form C * H or C * H**T where C = ( C1 C2 ) |
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* |
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LASTV = MAX( K, ILASLR( N, K, V, LDV ) ) |
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LASTC = ILASLR( M, LASTV, C, LDC ) |
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* |
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* W := C * V = (C1*V1 + C2*V2) (stored in WORK) |
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* |
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* W := C1 |
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* |
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DO 40 J = 1, K |
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CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 ) |
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40 CONTINUE |
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* |
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* W := W * V1 |
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* |
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CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
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$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
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IF( LASTV.GT.K ) THEN |
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* |
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* W := W + C2 * V2 |
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* |
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CALL SGEMM( 'No transpose', 'No transpose', |
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$ LASTC, K, LASTV-K, |
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$ ONE, C( 1, K+1 ), LDC, V( K+1, 1 ), LDV, |
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$ ONE, WORK, LDWORK ) |
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END IF |
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* |
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* W := W * T or W * T**T |
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* |
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CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit', |
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$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
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* |
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* C := C - W * V**T |
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* |
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IF( LASTV.GT.K ) THEN |
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* |
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* C2 := C2 - W * V2**T |
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* |
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CALL SGEMM( 'No transpose', 'Transpose', |
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$ LASTC, LASTV-K, K, |
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$ -ONE, WORK, LDWORK, V( K+1, 1 ), LDV, ONE, |
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$ C( 1, K+1 ), LDC ) |
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END IF |
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* |
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* W := W * V1**T |
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* |
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CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit', |
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$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
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* |
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* C1 := C1 - W |
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* |
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DO 60 J = 1, K |
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DO 50 I = 1, LASTC |
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C( I, J ) = C( I, J ) - WORK( I, J ) |
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50 CONTINUE |
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60 CONTINUE |
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END IF |
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* |
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ELSE |
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* |
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* Let V = ( V1 ) |
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* ( V2 ) (last K rows) |
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* where V2 is unit upper triangular. |
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* |
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IF( LSAME( SIDE, 'L' ) ) THEN |
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* |
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* Form H * C or H**T * C where C = ( C1 ) |
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* ( C2 ) |
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* |
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LASTV = MAX( K, ILASLR( M, K, V, LDV ) ) |
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LASTC = ILASLC( LASTV, N, C, LDC ) |
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* |
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* W := C**T * V = (C1**T * V1 + C2**T * V2) (stored in WORK) |
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* |
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* W := C2**T |
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* |
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DO 70 J = 1, K |
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CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC, |
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$ WORK( 1, J ), 1 ) |
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70 CONTINUE |
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* |
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* W := W * V2 |
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* |
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CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
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$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
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$ WORK, LDWORK ) |
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IF( LASTV.GT.K ) THEN |
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* |
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* W := W + C1**T*V1 |
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* |
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CALL SGEMM( 'Transpose', 'No transpose', |
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$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, |
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$ ONE, WORK, LDWORK ) |
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END IF |
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* |
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* W := W * T**T or W * T |
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* |
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CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit', |
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$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
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* |
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* C := C - V * W**T |
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* |
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IF( LASTV.GT.K ) THEN |
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* |
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* C1 := C1 - V1 * W**T |
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* |
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CALL SGEMM( 'No transpose', 'Transpose', |
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$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK, |
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$ ONE, C, LDC ) |
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END IF |
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* |
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* W := W * V2**T |
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* |
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CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', |
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$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
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$ WORK, LDWORK ) |
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* |
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* C2 := C2 - W**T |
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* |
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DO 90 J = 1, K |
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DO 80 I = 1, LASTC |
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C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J) |
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80 CONTINUE |
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90 CONTINUE |
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* |
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ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
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* |
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* Form C * H or C * H**T where C = ( C1 C2 ) |
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* |
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LASTV = MAX( K, ILASLR( N, K, V, LDV ) ) |
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LASTC = ILASLR( M, LASTV, C, LDC ) |
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* |
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* W := C * V = (C1*V1 + C2*V2) (stored in WORK) |
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* |
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* W := C2 |
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* |
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DO 100 J = 1, K |
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CALL SCOPY( LASTC, C( 1, N-K+J ), 1, WORK( 1, J ), 1 ) |
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100 CONTINUE |
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* |
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* W := W * V2 |
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* |
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CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
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$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
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$ WORK, LDWORK ) |
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IF( LASTV.GT.K ) THEN |
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* |
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* W := W + C1 * V1 |
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* |
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CALL SGEMM( 'No transpose', 'No transpose', |
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$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, |
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$ ONE, WORK, LDWORK ) |
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END IF |
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* |
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* W := W * T or W * T**T |
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* |
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CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit', |
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$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
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* |
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* C := C - W * V**T |
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* |
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IF( LASTV.GT.K ) THEN |
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* |
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* C1 := C1 - W * V1**T |
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* |
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CALL SGEMM( 'No transpose', 'Transpose', |
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$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV, |
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$ ONE, C, LDC ) |
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END IF |
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* |
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* W := W * V2**T |
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* |
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CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', |
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$ LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV, |
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$ WORK, LDWORK ) |
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* |
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* C2 := C2 - W |
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* |
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DO 120 J = 1, K |
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DO 110 I = 1, LASTC |
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C( I, LASTV-K+J ) = C( I, LASTV-K+J ) - WORK(I, J) |
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110 CONTINUE |
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120 CONTINUE |
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END IF |
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END IF |
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* |
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ELSE IF( LSAME( STOREV, 'R' ) ) THEN |
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* |
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IF( LSAME( DIRECT, 'F' ) ) THEN |
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* |
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* Let V = ( V1 V2 ) (V1: first K columns) |
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* where V1 is unit upper triangular. |
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* |
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IF( LSAME( SIDE, 'L' ) ) THEN |
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* |
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* Form H * C or H**T * C where C = ( C1 ) |
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* ( C2 ) |
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* |
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LASTV = MAX( K, ILASLC( K, M, V, LDV ) ) |
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LASTC = ILASLC( LASTV, N, C, LDC ) |
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* |
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* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK) |
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* |
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* W := C1**T |
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* |
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DO 130 J = 1, K |
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CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 ) |
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130 CONTINUE |
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* |
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* W := W * V1**T |
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* |
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CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', |
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$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
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IF( LASTV.GT.K ) THEN |
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* |
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* W := W + C2**T*V2**T |
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* |
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CALL SGEMM( 'Transpose', 'Transpose', |
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$ LASTC, K, LASTV-K, |
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$ ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV, |
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$ ONE, WORK, LDWORK ) |
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END IF |
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* |
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* W := W * T**T or W * T |
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* |
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CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit', |
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$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
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* |
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* C := C - V**T * W**T |
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* |
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IF( LASTV.GT.K ) THEN |
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* |
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* C2 := C2 - V2**T * W**T |
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* |
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CALL SGEMM( 'Transpose', 'Transpose', |
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$ LASTV-K, LASTC, K, |
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$ -ONE, V( 1, K+1 ), LDV, WORK, LDWORK, |
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$ ONE, C( K+1, 1 ), LDC ) |
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END IF |
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* |
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* W := W * V1 |
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* |
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CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
|
$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
|
* |
|
* C1 := C1 - W**T |
|
* |
|
DO 150 J = 1, K |
|
DO 140 I = 1, LASTC |
|
C( J, I ) = C( J, I ) - WORK( I, J ) |
|
140 CONTINUE |
|
150 CONTINUE |
|
* |
|
ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
|
* |
|
* Form C * H or C * H**T where C = ( C1 C2 ) |
|
* |
|
LASTV = MAX( K, ILASLC( K, N, V, LDV ) ) |
|
LASTC = ILASLR( M, LASTV, C, LDC ) |
|
* |
|
* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK) |
|
* |
|
* W := C1 |
|
* |
|
DO 160 J = 1, K |
|
CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 ) |
|
160 CONTINUE |
|
* |
|
* W := W * V1**T |
|
* |
|
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', |
|
$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
|
IF( LASTV.GT.K ) THEN |
|
* |
|
* W := W + C2 * V2**T |
|
* |
|
CALL SGEMM( 'No transpose', 'Transpose', |
|
$ LASTC, K, LASTV-K, |
|
$ ONE, C( 1, K+1 ), LDC, V( 1, K+1 ), LDV, |
|
$ ONE, WORK, LDWORK ) |
|
END IF |
|
* |
|
* W := W * T or W * T**T |
|
* |
|
CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit', |
|
$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
|
* |
|
* C := C - W * V |
|
* |
|
IF( LASTV.GT.K ) THEN |
|
* |
|
* C2 := C2 - W * V2 |
|
* |
|
CALL SGEMM( 'No transpose', 'No transpose', |
|
$ LASTC, LASTV-K, K, |
|
$ -ONE, WORK, LDWORK, V( 1, K+1 ), LDV, |
|
$ ONE, C( 1, K+1 ), LDC ) |
|
END IF |
|
* |
|
* W := W * V1 |
|
* |
|
CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit', |
|
$ LASTC, K, ONE, V, LDV, WORK, LDWORK ) |
|
* |
|
* C1 := C1 - W |
|
* |
|
DO 180 J = 1, K |
|
DO 170 I = 1, LASTC |
|
C( I, J ) = C( I, J ) - WORK( I, J ) |
|
170 CONTINUE |
|
180 CONTINUE |
|
* |
|
END IF |
|
* |
|
ELSE |
|
* |
|
* Let V = ( V1 V2 ) (V2: last K columns) |
|
* where V2 is unit lower triangular. |
|
* |
|
IF( LSAME( SIDE, 'L' ) ) THEN |
|
* |
|
* Form H * C or H**T * C where C = ( C1 ) |
|
* ( C2 ) |
|
* |
|
LASTV = MAX( K, ILASLC( K, M, V, LDV ) ) |
|
LASTC = ILASLC( LASTV, N, C, LDC ) |
|
* |
|
* W := C**T * V**T = (C1**T * V1**T + C2**T * V2**T) (stored in WORK) |
|
* |
|
* W := C2**T |
|
* |
|
DO 190 J = 1, K |
|
CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC, |
|
$ WORK( 1, J ), 1 ) |
|
190 CONTINUE |
|
* |
|
* W := W * V2**T |
|
* |
|
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit', |
|
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
|
$ WORK, LDWORK ) |
|
IF( LASTV.GT.K ) THEN |
|
* |
|
* W := W + C1**T * V1**T |
|
* |
|
CALL SGEMM( 'Transpose', 'Transpose', |
|
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, |
|
$ ONE, WORK, LDWORK ) |
|
END IF |
|
* |
|
* W := W * T**T or W * T |
|
* |
|
CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit', |
|
$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
|
* |
|
* C := C - V**T * W**T |
|
* |
|
IF( LASTV.GT.K ) THEN |
|
* |
|
* C1 := C1 - V1**T * W**T |
|
* |
|
CALL SGEMM( 'Transpose', 'Transpose', |
|
$ LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK, |
|
$ ONE, C, LDC ) |
|
END IF |
|
* |
|
* W := W * V2 |
|
* |
|
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
|
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
|
$ WORK, LDWORK ) |
|
* |
|
* C2 := C2 - W**T |
|
* |
|
DO 210 J = 1, K |
|
DO 200 I = 1, LASTC |
|
C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J) |
|
200 CONTINUE |
|
210 CONTINUE |
|
* |
|
ELSE IF( LSAME( SIDE, 'R' ) ) THEN |
|
* |
|
* Form C * H or C * H**T where C = ( C1 C2 ) |
|
* |
|
LASTV = MAX( K, ILASLC( K, N, V, LDV ) ) |
|
LASTC = ILASLR( M, LASTV, C, LDC ) |
|
* |
|
* W := C * V**T = (C1*V1**T + C2*V2**T) (stored in WORK) |
|
* |
|
* W := C2 |
|
* |
|
DO 220 J = 1, K |
|
CALL SCOPY( LASTC, C( 1, LASTV-K+J ), 1, |
|
$ WORK( 1, J ), 1 ) |
|
220 CONTINUE |
|
* |
|
* W := W * V2**T |
|
* |
|
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit', |
|
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
|
$ WORK, LDWORK ) |
|
IF( LASTV.GT.K ) THEN |
|
* |
|
* W := W + C1 * V1**T |
|
* |
|
CALL SGEMM( 'No transpose', 'Transpose', |
|
$ LASTC, K, LASTV-K, ONE, C, LDC, V, LDV, |
|
$ ONE, WORK, LDWORK ) |
|
END IF |
|
* |
|
* W := W * T or W * T**T |
|
* |
|
CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit', |
|
$ LASTC, K, ONE, T, LDT, WORK, LDWORK ) |
|
* |
|
* C := C - W * V |
|
* |
|
IF( LASTV.GT.K ) THEN |
|
* |
|
* C1 := C1 - W * V1 |
|
* |
|
CALL SGEMM( 'No transpose', 'No transpose', |
|
$ LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV, |
|
$ ONE, C, LDC ) |
|
END IF |
|
* |
|
* W := W * V2 |
|
* |
|
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit', |
|
$ LASTC, K, ONE, V( 1, LASTV-K+1 ), LDV, |
|
$ WORK, LDWORK ) |
|
* |
|
* C1 := C1 - W |
|
* |
|
DO 240 J = 1, K |
|
DO 230 I = 1, LASTC |
|
C( I, LASTV-K+J ) = C( I, LASTV-K+J ) |
|
$ - WORK( I, J ) |
|
230 CONTINUE |
|
240 CONTINUE |
|
* |
|
END IF |
|
* |
|
END IF |
|
END IF |
|
* |
|
RETURN |
|
* |
|
* End of SLARFB |
|
* |
|
END
|
|
|