Add support for Sparse QR factorization

1 files changed, 763 insertions, 0 deletions

diff --git a/lapack/slarfb.f b/lapack/slarfb.f
new file mode 100644
index 000000000..eb95990b3
--- /dev/null
+++ b/lapack/slarfb.f
@@ -0,0 +1,763 @@
+*> \brief \b SLARFB
+*
+*  =========== DOCUMENTATION ===========
+*
+* Online html documentation available at 
+*            http://www.netlib.org/lapack/explore-html/ 
+*
+*> \htmlonly
+*> Download SLARFB + dependencies 
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/slarfb.f"> 
+*> [TGZ]</a> 
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/slarfb.f"> 
+*> [ZIP]</a> 
+*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/slarfb.f"> 
+*> [TXT]</a>
+*> \endhtmlonly 
+*
+*  Definition:
+*  ===========
+*
+*       SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
+*                          T, LDT, C, LDC, WORK, LDWORK )
+* 
+*       .. Scalar Arguments ..
+*       CHARACTER          DIRECT, SIDE, STOREV, TRANS
+*       INTEGER            K, LDC, LDT, LDV, LDWORK, M, N
+*       ..
+*       .. Array Arguments ..
+*       REAL               C( LDC, * ), T( LDT, * ), V( LDV, * ),
+*      $                   WORK( LDWORK, * )
+*       ..
+*  
+*
+*> \par Purpose:
+*  =============
+*>
+*> \verbatim
+*>
+*> SLARFB applies a real block reflector H or its transpose H**T to a
+*> real m by n matrix C, from either the left or the right.
+*> \endverbatim
+*
+*  Arguments:
+*  ==========
+*
+*> \param[in] SIDE
+*> \verbatim
+*>          SIDE is CHARACTER*1
+*>          = 'L': apply H or H**T from the Left
+*>          = 'R': apply H or H**T from the Right
+*> \endverbatim
+*>
+*> \param[in] TRANS
+*> \verbatim
+*>          TRANS is CHARACTER*1
+*>          = 'N': apply H (No transpose)
+*>          = 'T': apply H**T (Transpose)
+*> \endverbatim
+*>
+*> \param[in] DIRECT
+*> \verbatim
+*>          DIRECT is CHARACTER*1
+*>          Indicates how H is formed from a product of elementary
+*>          reflectors
+*>          = 'F': H = H(1) H(2) . . . H(k) (Forward)
+*>          = 'B': H = H(k) . . . H(2) H(1) (Backward)
+*> \endverbatim
+*>
+*> \param[in] STOREV
+*> \verbatim
+*>          STOREV is CHARACTER*1
+*>          Indicates how the vectors which define the elementary
+*>          reflectors are stored:
+*>          = 'C': Columnwise
+*>          = 'R': Rowwise
+*> \endverbatim
+*>
+*> \param[in] M
+*> \verbatim
+*>          M is INTEGER
+*>          The number of rows of the matrix C.
+*> \endverbatim
+*>
+*> \param[in] N
+*> \verbatim
+*>          N is INTEGER
+*>          The number of columns of the matrix C.
+*> \endverbatim
+*>
+*> \param[in] K
+*> \verbatim
+*>          K is INTEGER
+*>          The order of the matrix T (= the number of elementary
+*>          reflectors whose product defines the block reflector).
+*> \endverbatim
+*>
+*> \param[in] V
+*> \verbatim
+*>          V is REAL array, dimension
+*>                                (LDV,K) if STOREV = 'C'
+*>                                (LDV,M) if STOREV = 'R' and SIDE = 'L'
+*>                                (LDV,N) if STOREV = 'R' and SIDE = 'R'
+*>          The matrix V. See Further Details.
+*> \endverbatim
+*>
+*> \param[in] LDV
+*> \verbatim
+*>          LDV is INTEGER
+*>          The leading dimension of the array V.
+*>          If STOREV = 'C' and SIDE = 'L', LDV >= max(1,M);
+*>          if STOREV = 'C' and SIDE = 'R', LDV >= max(1,N);
+*>          if STOREV = 'R', LDV >= K.
+*> \endverbatim
+*>
+*> \param[in] T
+*> \verbatim
+*>          T is REAL array, dimension (LDT,K)
+*>          The triangular k by k matrix T in the representation of the
+*>          block reflector.
+*> \endverbatim
+*>
+*> \param[in] LDT
+*> \verbatim
+*>          LDT is INTEGER
+*>          The leading dimension of the array T. LDT >= K.
+*> \endverbatim
+*>
+*> \param[in,out] C
+*> \verbatim
+*>          C is REAL array, dimension (LDC,N)
+*>          On entry, the m by n matrix C.
+*>          On exit, C is overwritten by H*C or H**T*C or C*H or C*H**T.
+*> \endverbatim
+*>
+*> \param[in] LDC
+*> \verbatim
+*>          LDC is INTEGER
+*>          The leading dimension of the array C. LDC >= max(1,M).
+*> \endverbatim
+*>
+*> \param[out] WORK
+*> \verbatim
+*>          WORK is REAL array, dimension (LDWORK,K)
+*> \endverbatim
+*>
+*> \param[in] LDWORK
+*> \verbatim
+*>          LDWORK is INTEGER
+*>          The leading dimension of the array WORK.
+*>          If SIDE = 'L', LDWORK >= max(1,N);
+*>          if SIDE = 'R', LDWORK >= max(1,M).
+*> \endverbatim
+*
+*  Authors:
+*  ========
+*
+*> \author Univ. of Tennessee 
+*> \author Univ. of California Berkeley 
+*> \author Univ. of Colorado Denver 
+*> \author NAG Ltd. 
+*
+*> \date November 2011
+*
+*> \ingroup realOTHERauxiliary
+*
+*> \par Further Details:
+*  =====================
+*>
+*> \verbatim
+*>
+*>  The shape of the matrix V and the storage of the vectors which define
+*>  the H(i) is best illustrated by the following example with n = 5 and
+*>  k = 3. The elements equal to 1 are not stored; the corresponding
+*>  array elements are modified but restored on exit. The rest of the
+*>  array is not used.
+*>
+*>  DIRECT = 'F' and STOREV = 'C':         DIRECT = 'F' and STOREV = 'R':
+*>
+*>               V = (  1       )                 V = (  1 v1 v1 v1 v1 )
+*>                   ( v1  1    )                     (     1 v2 v2 v2 )
+*>                   ( v1 v2  1 )                     (        1 v3 v3 )
+*>                   ( v1 v2 v3 )
+*>                   ( v1 v2 v3 )
+*>
+*>  DIRECT = 'B' and STOREV = 'C':         DIRECT = 'B' and STOREV = 'R':
+*>
+*>               V = ( v1 v2 v3 )                 V = ( v1 v1  1       )
+*>                   ( v1 v2 v3 )                     ( v2 v2 v2  1    )
+*>                   (  1 v2 v3 )                     ( v3 v3 v3 v3  1 )
+*>                   (     1 v3 )
+*>                   (        1 )
+*> \endverbatim
+*>
+*  =====================================================================
+      SUBROUTINE SLARFB( SIDE, TRANS, DIRECT, STOREV, M, N, K, V, LDV,
+     $                   T, LDT, C, LDC, WORK, LDWORK )
+*
+*  -- LAPACK auxiliary routine (version 3.4.0) --
+*  -- LAPACK is a software package provided by Univ. of Tennessee,    --
+*  -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
+*     November 2011
+*
+*     .. Scalar Arguments ..
+      CHARACTER          DIRECT, SIDE, STOREV, TRANS
+      INTEGER            K, LDC, LDT, LDV, LDWORK, M, N
+*     ..
+*     .. Array Arguments ..
+      REAL               C( LDC, * ), T( LDT, * ), V( LDV, * ),
+     $                   WORK( LDWORK, * )
+*     ..
+*
+*  =====================================================================
+*
+*     .. Parameters ..
+      REAL               ONE
+      PARAMETER          ( ONE = 1.0E+0 )
+*     ..
+*     .. Local Scalars ..
+      CHARACTER          TRANST
+      INTEGER            I, J, LASTV, LASTC
+*     ..
+*     .. External Functions ..
+      LOGICAL            LSAME
+      INTEGER            ILASLR, ILASLC
+      EXTERNAL           LSAME, ILASLR, ILASLC
+*     ..
+*     .. External Subroutines ..
+      EXTERNAL           SCOPY, SGEMM, STRMM
+*     ..
+*     .. Executable Statements ..
+*
+*     Quick return if possible
+*
+      IF( M.LE.0 .OR. N.LE.0 )
+     $   RETURN
+*
+      IF( LSAME( TRANS, 'N' ) ) THEN
+         TRANST = 'T'
+      ELSE
+         TRANST = 'N'
+      END IF
+*
+      IF( LSAME( STOREV, 'C' ) ) THEN
+*
+         IF( LSAME( DIRECT, 'F' ) ) THEN
+*
+*           Let  V =  ( V1 )    (first K rows)
+*                     ( V2 )
+*           where  V1  is unit lower triangular.
+*
+            IF( LSAME( SIDE, 'L' ) ) THEN
+*
+*              Form  H * C  or  H**T * C  where  C = ( C1 )
+*                                                    ( C2 )
+*
+               LASTV = MAX( K, ILASLR( M, K, V, LDV ) )
+               LASTC = ILASLC( LASTV, N, C, LDC )
+*
+*              W := C**T * V  =  (C1**T * V1 + C2**T * V2)  (stored in WORK)
+*
+*              W := C1**T
+*
+               DO 10 J = 1, K
+                  CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
+   10          CONTINUE
+*
+*              W := W * V1
+*
+               CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
+     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
+               IF( LASTV.GT.K ) THEN
+*
+*                 W := W + C2**T *V2
+*
+                  CALL SGEMM( 'Transpose', 'No transpose',
+     $                 LASTC, K, LASTV-K,
+     $                 ONE, C( K+1, 1 ), LDC, V( K+1, 1 ), LDV,
+     $                 ONE, WORK, LDWORK )
+               END IF
+*
+*              W := W * T**T  or  W * T
+*
+               CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit',
+     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
+*
+*              C := C - V * W**T
+*
+               IF( LASTV.GT.K ) THEN
+*
+*                 C2 := C2 - V2 * W**T
+*
+                  CALL SGEMM( 'No transpose', 'Transpose',
+     $                 LASTV-K, LASTC, K,
+     $                 -ONE, V( K+1, 1 ), LDV, WORK, LDWORK, ONE,
+     $                 C( K+1, 1 ), LDC )
+               END IF
+*
+*              W := W * V1**T
+*
+               CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
+     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
+*
+*              C1 := C1 - W**T
+*
+               DO 30 J = 1, K
+                  DO 20 I = 1, LASTC
+                     C( J, I ) = C( J, I ) - WORK( I, J )
+   20             CONTINUE
+   30          CONTINUE
+*
+            ELSE IF( LSAME( SIDE, 'R' ) ) THEN
+*
+*              Form  C * H  or  C * H**T  where  C = ( C1  C2 )
+*
+               LASTV = MAX( K, ILASLR( N, K, V, LDV ) )
+               LASTC = ILASLR( M, LASTV, C, LDC )
+*
+*              W := C * V  =  (C1*V1 + C2*V2)  (stored in WORK)
+*
+*              W := C1
+*
+               DO 40 J = 1, K
+                  CALL SCOPY( LASTC, C( 1, J ), 1, WORK( 1, J ), 1 )
+   40          CONTINUE
+*
+*              W := W * V1
+*
+               CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit',
+     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
+               IF( LASTV.GT.K ) THEN
+*
+*                 W := W + C2 * V2
+*
+                  CALL SGEMM( 'No transpose', 'No transpose',
+     $                 LASTC, K, LASTV-K,
+     $                 ONE, C( 1, K+1 ), LDC, V( K+1, 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**T
+*
+               IF( LASTV.GT.K ) THEN
+*
+*                 C2 := C2 - W * V2**T
+*
+                  CALL SGEMM( 'No transpose', 'Transpose',
+     $                 LASTC, LASTV-K, K,
+     $                 -ONE, WORK, LDWORK, V( K+1, 1 ), LDV, ONE,
+     $                 C( 1, K+1 ), LDC )
+               END IF
+*
+*              W := W * V1**T
+*
+               CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit',
+     $              LASTC, K, ONE, V, LDV, WORK, LDWORK )
+*
+*              C1 := C1 - W
+*
+               DO 60 J = 1, K
+                  DO 50 I = 1, LASTC
+                     C( I, J ) = C( I, J ) - WORK( I, J )
+   50             CONTINUE
+   60          CONTINUE
+            END IF
+*
+         ELSE
+*
+*           Let  V =  ( V1 )
+*                     ( V2 )    (last K rows)
+*           where  V2  is unit upper triangular.
+*
+            IF( LSAME( SIDE, 'L' ) ) THEN
+*
+*              Form  H * C  or  H**T * C  where  C = ( C1 )
+*                                                    ( C2 )
+*
+               LASTV = MAX( K, ILASLR( M, K, V, LDV ) )
+               LASTC = ILASLC( LASTV, N, C, LDC )
+*
+*              W := C**T * V  =  (C1**T * V1 + C2**T * V2)  (stored in WORK)
+*
+*              W := C2**T
+*
+               DO 70 J = 1, K
+                  CALL SCOPY( LASTC, C( LASTV-K+J, 1 ), LDC,
+     $                 WORK( 1, J ), 1 )
+   70          CONTINUE
+*
+*              W := W * V2
+*
+               CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
+     $              LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
+     $              WORK, LDWORK )
+               IF( LASTV.GT.K ) THEN
+*
+*                 W := W + C1**T*V1
+*
+                  CALL SGEMM( 'Transpose', 'No 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 * W**T
+*
+               IF( LASTV.GT.K ) THEN
+*
+*                 C1 := C1 - V1 * W**T
+*
+                  CALL SGEMM( 'No transpose', 'Transpose',
+     $                 LASTV-K, LASTC, K, -ONE, V, LDV, WORK, LDWORK,
+     $                 ONE, C, LDC )
+               END IF
+*
+*              W := W * V2**T
+*
+               CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
+     $              LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
+     $              WORK, LDWORK )
+*
+*              C2 := C2 - W**T
+*
+               DO 90 J = 1, K
+                  DO 80 I = 1, LASTC
+                     C( LASTV-K+J, I ) = C( LASTV-K+J, I ) - WORK(I, J)
+   80             CONTINUE
+   90          CONTINUE
+*
+            ELSE IF( LSAME( SIDE, 'R' ) ) THEN
+*
+*              Form  C * H  or  C * H**T  where  C = ( C1  C2 )
+*
+               LASTV = MAX( K, ILASLR( N, K, V, LDV ) )
+               LASTC = ILASLR( M, LASTV, C, LDC )
+*
+*              W := C * V  =  (C1*V1 + C2*V2)  (stored in WORK)
+*
+*              W := C2
+*
+               DO 100 J = 1, K
+                  CALL SCOPY( LASTC, C( 1, N-K+J ), 1, WORK( 1, J ), 1 )
+  100          CONTINUE
+*
+*              W := W * V2
+*
+               CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit',
+     $              LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
+     $              WORK, LDWORK )
+               IF( LASTV.GT.K ) THEN
+*
+*                 W := W + C1 * V1
+*
+                  CALL SGEMM( 'No transpose', 'No 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**T
+*
+               IF( LASTV.GT.K ) THEN
+*
+*                 C1 := C1 - W * V1**T
+*
+                  CALL SGEMM( 'No transpose', 'Transpose',
+     $                 LASTC, LASTV-K, K, -ONE, WORK, LDWORK, V, LDV,
+     $                 ONE, C, LDC )
+               END IF
+*
+*              W := W * V2**T
+*
+               CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit',
+     $              LASTC, K, ONE, V( LASTV-K+1, 1 ), LDV,
+     $              WORK, LDWORK )
+*
+*              C2 := C2 - W
+*
+               DO 120 J = 1, K
+                  DO 110 I = 1, LASTC
+                     C( I, LASTV-K+J ) = C( I, LASTV-K+J ) - WORK(I, J)
+  110             CONTINUE
+  120          CONTINUE
+            END IF
+         END IF
+*
+      ELSE IF( LSAME( STOREV, 'R' ) ) THEN
+*
+         IF( LSAME( DIRECT, 'F' ) ) THEN
+*
+*           Let  V =  ( V1  V2 )    (V1: first K columns)
+*           where  V1  is unit upper 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 := C1**T
+*
+               DO 130 J = 1, K
+                  CALL SCOPY( LASTC, C( J, 1 ), LDC, WORK( 1, J ), 1 )
+  130          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**T*V2**T
+*
+                  CALL SGEMM( 'Transpose', 'Transpose',
+     $                 LASTC, K, LASTV-K,
+     $                 ONE, C( K+1, 1 ), LDC, V( 1, K+1 ), LDV,
+     $                 ONE, WORK, LDWORK )
+               END IF
+*
+*              W := W * T**T  or  W * T
+*
+               CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit',
+     $              LASTC, K, ONE, T, LDT, WORK, LDWORK )
+*
+*              C := C - V**T * W**T
+*
+               IF( LASTV.GT.K ) THEN
+*
+*                 C2 := C2 - V2**T * W**T
+*
+                  CALL SGEMM( 'Transpose', 'Transpose',
+     $                 LASTV-K, LASTC, K,
+     $                 -ONE, V( 1, K+1 ), LDV, WORK, LDWORK,
+     $                 ONE, C( K+1, 1 ), LDC )
+               END IF
+*
+*              W := W * V1
+*
+               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