📄 slarfb.f
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*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H' where C = ( C1 C2 )
*
* W := C * V = (C1*V1 + C2*V2) (stored in WORK)
*
* W := C2
*
DO 100 J = 1, K
CALL SCOPY( M, C( 1, N-K+J ), 1, WORK( 1, J ), 1 )
100 CONTINUE
*
* W := W * V2
*
CALL STRMM( 'Right', 'Upper', 'No transpose', 'Unit', M,
$ K, ONE, V( N-K+1, 1 ), LDV, WORK, LDWORK )
IF( N.GT.K ) THEN
*
* W := W + C1 * V1
*
CALL SGEMM( 'No transpose', 'No transpose', M, K, N-K,
$ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T'
*
CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit', M, K,
$ ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V'
*
IF( N.GT.K ) THEN
*
* C1 := C1 - W * V1'
*
CALL SGEMM( 'No transpose', 'Transpose', M, N-K, K,
$ -ONE, WORK, LDWORK, V, LDV, ONE, C, LDC )
END IF
*
* W := W * V2'
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', M, K,
$ ONE, V( N-K+1, 1 ), LDV, WORK, LDWORK )
*
* C2 := C2 - W
*
DO 120 J = 1, K
DO 110 I = 1, M
C( I, N-K+J ) = C( I, N-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' * C where C = ( C1 )
* ( C2 )
*
* W := C' * V' = (C1'*V1' + C2'*V2') (stored in WORK)
*
* W := C1'
*
DO 130 J = 1, K
CALL SCOPY( N, C( J, 1 ), LDC, WORK( 1, J ), 1 )
130 CONTINUE
*
* W := W * V1'
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', N, K,
$ ONE, V, LDV, WORK, LDWORK )
IF( M.GT.K ) THEN
*
* W := W + C2'*V2'
*
CALL SGEMM( 'Transpose', 'Transpose', N, K, M-K, ONE,
$ C( K+1, 1 ), LDC, V( 1, K+1 ), LDV, ONE,
$ WORK, LDWORK )
END IF
*
* W := W * T' or W * T
*
CALL STRMM( 'Right', 'Upper', TRANST, 'Non-unit', N, K,
$ ONE, T, LDT, WORK, LDWORK )
*
* C := C - V' * W'
*
IF( M.GT.K ) THEN
*
* C2 := C2 - V2' * W'
*
CALL SGEMM( 'Transpose', 'Transpose', M-K, N, 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', N,
$ K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W'
*
DO 150 J = 1, K
DO 140 I = 1, N
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' where C = ( C1 C2 )
*
* W := C * V' = (C1*V1' + C2*V2') (stored in WORK)
*
* W := C1
*
DO 160 J = 1, K
CALL SCOPY( M, C( 1, J ), 1, WORK( 1, J ), 1 )
160 CONTINUE
*
* W := W * V1'
*
CALL STRMM( 'Right', 'Upper', 'Transpose', 'Unit', M, K,
$ ONE, V, LDV, WORK, LDWORK )
IF( N.GT.K ) THEN
*
* W := W + C2 * V2'
*
CALL SGEMM( 'No transpose', 'Transpose', M, K, N-K,
$ ONE, C( 1, K+1 ), LDC, V( 1, K+1 ), LDV,
$ ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T'
*
CALL STRMM( 'Right', 'Upper', TRANS, 'Non-unit', M, K,
$ ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( N.GT.K ) THEN
*
* C2 := C2 - W * V2
*
CALL SGEMM( 'No transpose', 'No transpose', M, N-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', M,
$ K, ONE, V, LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 180 J = 1, K
DO 170 I = 1, M
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' * C where C = ( C1 )
* ( C2 )
*
* W := C' * V' = (C1'*V1' + C2'*V2') (stored in WORK)
*
* W := C2'
*
DO 190 J = 1, K
CALL SCOPY( N, C( M-K+J, 1 ), LDC, WORK( 1, J ), 1 )
190 CONTINUE
*
* W := W * V2'
*
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit', N, K,
$ ONE, V( 1, M-K+1 ), LDV, WORK, LDWORK )
IF( M.GT.K ) THEN
*
* W := W + C1'*V1'
*
CALL SGEMM( 'Transpose', 'Transpose', N, K, M-K, ONE,
$ C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T' or W * T
*
CALL STRMM( 'Right', 'Lower', TRANST, 'Non-unit', N, K,
$ ONE, T, LDT, WORK, LDWORK )
*
* C := C - V' * W'
*
IF( M.GT.K ) THEN
*
* C1 := C1 - V1' * W'
*
CALL SGEMM( 'Transpose', 'Transpose', M-K, N, K, -ONE,
$ V, LDV, WORK, LDWORK, ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit', N,
$ K, ONE, V( 1, M-K+1 ), LDV, WORK, LDWORK )
*
* C2 := C2 - W'
*
DO 210 J = 1, K
DO 200 I = 1, N
C( M-K+J, I ) = C( M-K+J, I ) - WORK( I, J )
200 CONTINUE
210 CONTINUE
*
ELSE IF( LSAME( SIDE, 'R' ) ) THEN
*
* Form C * H or C * H' where C = ( C1 C2 )
*
* W := C * V' = (C1*V1' + C2*V2') (stored in WORK)
*
* W := C2
*
DO 220 J = 1, K
CALL SCOPY( M, C( 1, N-K+J ), 1, WORK( 1, J ), 1 )
220 CONTINUE
*
* W := W * V2'
*
CALL STRMM( 'Right', 'Lower', 'Transpose', 'Unit', M, K,
$ ONE, V( 1, N-K+1 ), LDV, WORK, LDWORK )
IF( N.GT.K ) THEN
*
* W := W + C1 * V1'
*
CALL SGEMM( 'No transpose', 'Transpose', M, K, N-K,
$ ONE, C, LDC, V, LDV, ONE, WORK, LDWORK )
END IF
*
* W := W * T or W * T'
*
CALL STRMM( 'Right', 'Lower', TRANS, 'Non-unit', M, K,
$ ONE, T, LDT, WORK, LDWORK )
*
* C := C - W * V
*
IF( N.GT.K ) THEN
*
* C1 := C1 - W * V1
*
CALL SGEMM( 'No transpose', 'No transpose', M, N-K, K,
$ -ONE, WORK, LDWORK, V, LDV, ONE, C, LDC )
END IF
*
* W := W * V2
*
CALL STRMM( 'Right', 'Lower', 'No transpose', 'Unit', M,
$ K, ONE, V( 1, N-K+1 ), LDV, WORK, LDWORK )
*
* C1 := C1 - W
*
DO 240 J = 1, K
DO 230 I = 1, M
C( I, N-K+J ) = C( I, N-K+J ) - WORK( I, J )
230 CONTINUE
240 CONTINUE
*
END IF
*
END IF
END IF
*
RETURN
*
* End of SLARFB
*
END
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