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Mise à jour de lapack vers la version 3.3.0.
1: SUBROUTINE DLARZB( SIDE, TRANS, DIRECT, STOREV, M, N, K, L, V, 2: $ LDV, T, LDT, C, LDC, WORK, LDWORK ) 3: * 4: * -- LAPACK routine (version 3.2) -- 5: * -- LAPACK is a software package provided by Univ. of Tennessee, -- 6: * -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- 7: * November 2006 8: * 9: * .. Scalar Arguments .. 10: CHARACTER DIRECT, SIDE, STOREV, TRANS 11: INTEGER K, L, LDC, LDT, LDV, LDWORK, M, N 12: * .. 13: * .. Array Arguments .. 14: DOUBLE PRECISION C( LDC, * ), T( LDT, * ), V( LDV, * ), 15: $ WORK( LDWORK, * ) 16: * .. 17: * 18: * Purpose 19: * ======= 20: * 21: * DLARZB applies a real block reflector H or its transpose H**T to 22: * a real distributed M-by-N C from the left or the right. 23: * 24: * Currently, only STOREV = 'R' and DIRECT = 'B' are supported. 25: * 26: * Arguments 27: * ========= 28: * 29: * SIDE (input) CHARACTER*1 30: * = 'L': apply H or H' from the Left 31: * = 'R': apply H or H' from the Right 32: * 33: * TRANS (input) CHARACTER*1 34: * = 'N': apply H (No transpose) 35: * = 'C': apply H' (Transpose) 36: * 37: * DIRECT (input) CHARACTER*1 38: * Indicates how H is formed from a product of elementary 39: * reflectors 40: * = 'F': H = H(1) H(2) . . . H(k) (Forward, not supported yet) 41: * = 'B': H = H(k) . . . H(2) H(1) (Backward) 42: * 43: * STOREV (input) CHARACTER*1 44: * Indicates how the vectors which define the elementary 45: * reflectors are stored: 46: * = 'C': Columnwise (not supported yet) 47: * = 'R': Rowwise 48: * 49: * M (input) INTEGER 50: * The number of rows of the matrix C. 51: * 52: * N (input) INTEGER 53: * The number of columns of the matrix C. 54: * 55: * K (input) INTEGER 56: * The order of the matrix T (= the number of elementary 57: * reflectors whose product defines the block reflector). 58: * 59: * L (input) INTEGER 60: * The number of columns of the matrix V containing the 61: * meaningful part of the Householder reflectors. 62: * If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0. 63: * 64: * V (input) DOUBLE PRECISION array, dimension (LDV,NV). 65: * If STOREV = 'C', NV = K; if STOREV = 'R', NV = L. 66: * 67: * LDV (input) INTEGER 68: * The leading dimension of the array V. 69: * If STOREV = 'C', LDV >= L; if STOREV = 'R', LDV >= K. 70: * 71: * T (input) DOUBLE PRECISION array, dimension (LDT,K) 72: * The triangular K-by-K matrix T in the representation of the 73: * block reflector. 74: * 75: * LDT (input) INTEGER 76: * The leading dimension of the array T. LDT >= K. 77: * 78: * C (input/output) DOUBLE PRECISION array, dimension (LDC,N) 79: * On entry, the M-by-N matrix C. 80: * On exit, C is overwritten by H*C or H'*C or C*H or C*H'. 81: * 82: * LDC (input) INTEGER 83: * The leading dimension of the array C. LDC >= max(1,M). 84: * 85: * WORK (workspace) DOUBLE PRECISION array, dimension (LDWORK,K) 86: * 87: * LDWORK (input) INTEGER 88: * The leading dimension of the array WORK. 89: * If SIDE = 'L', LDWORK >= max(1,N); 90: * if SIDE = 'R', LDWORK >= max(1,M). 91: * 92: * Further Details 93: * =============== 94: * 95: * Based on contributions by 96: * A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA 97: * 98: * ===================================================================== 99: * 100: * .. Parameters .. 101: DOUBLE PRECISION ONE 102: PARAMETER ( ONE = 1.0D+0 ) 103: * .. 104: * .. Local Scalars .. 105: CHARACTER TRANST 106: INTEGER I, INFO, J 107: * .. 108: * .. External Functions .. 109: LOGICAL LSAME 110: EXTERNAL LSAME 111: * .. 112: * .. External Subroutines .. 113: EXTERNAL DCOPY, DGEMM, DTRMM, XERBLA 114: * .. 115: * .. Executable Statements .. 116: * 117: * Quick return if possible 118: * 119: IF( M.LE.0 .OR. N.LE.0 ) 120: $ RETURN 121: * 122: * Check for currently supported options 123: * 124: INFO = 0 125: IF( .NOT.LSAME( DIRECT, 'B' ) ) THEN 126: INFO = -3 127: ELSE IF( .NOT.LSAME( STOREV, 'R' ) ) THEN 128: INFO = -4 129: END IF 130: IF( INFO.NE.0 ) THEN 131: CALL XERBLA( 'DLARZB', -INFO ) 132: RETURN 133: END IF 134: * 135: IF( LSAME( TRANS, 'N' ) ) THEN 136: TRANST = 'T' 137: ELSE 138: TRANST = 'N' 139: END IF 140: * 141: IF( LSAME( SIDE, 'L' ) ) THEN 142: * 143: * Form H * C or H' * C 144: * 145: * W( 1:n, 1:k ) = C( 1:k, 1:n )' 146: * 147: DO 10 J = 1, K 148: CALL DCOPY( N, C( J, 1 ), LDC, WORK( 1, J ), 1 ) 149: 10 CONTINUE 150: * 151: * W( 1:n, 1:k ) = W( 1:n, 1:k ) + ... 152: * C( m-l+1:m, 1:n )' * V( 1:k, 1:l )' 153: * 154: IF( L.GT.0 ) 155: $ CALL DGEMM( 'Transpose', 'Transpose', N, K, L, ONE, 156: $ C( M-L+1, 1 ), LDC, V, LDV, ONE, WORK, LDWORK ) 157: * 158: * W( 1:n, 1:k ) = W( 1:n, 1:k ) * T' or W( 1:m, 1:k ) * T 159: * 160: CALL DTRMM( 'Right', 'Lower', TRANST, 'Non-unit', N, K, ONE, T, 161: $ LDT, WORK, LDWORK ) 162: * 163: * C( 1:k, 1:n ) = C( 1:k, 1:n ) - W( 1:n, 1:k )' 164: * 165: DO 30 J = 1, N 166: DO 20 I = 1, K 167: C( I, J ) = C( I, J ) - WORK( J, I ) 168: 20 CONTINUE 169: 30 CONTINUE 170: * 171: * C( m-l+1:m, 1:n ) = C( m-l+1:m, 1:n ) - ... 172: * V( 1:k, 1:l )' * W( 1:n, 1:k )' 173: * 174: IF( L.GT.0 ) 175: $ CALL DGEMM( 'Transpose', 'Transpose', L, N, K, -ONE, V, LDV, 176: $ WORK, LDWORK, ONE, C( M-L+1, 1 ), LDC ) 177: * 178: ELSE IF( LSAME( SIDE, 'R' ) ) THEN 179: * 180: * Form C * H or C * H' 181: * 182: * W( 1:m, 1:k ) = C( 1:m, 1:k ) 183: * 184: DO 40 J = 1, K 185: CALL DCOPY( M, C( 1, J ), 1, WORK( 1, J ), 1 ) 186: 40 CONTINUE 187: * 188: * W( 1:m, 1:k ) = W( 1:m, 1:k ) + ... 189: * C( 1:m, n-l+1:n ) * V( 1:k, 1:l )' 190: * 191: IF( L.GT.0 ) 192: $ CALL DGEMM( 'No transpose', 'Transpose', M, K, L, ONE, 193: $ C( 1, N-L+1 ), LDC, V, LDV, ONE, WORK, LDWORK ) 194: * 195: * W( 1:m, 1:k ) = W( 1:m, 1:k ) * T or W( 1:m, 1:k ) * T' 196: * 197: CALL DTRMM( 'Right', 'Lower', TRANS, 'Non-unit', M, K, ONE, T, 198: $ LDT, WORK, LDWORK ) 199: * 200: * C( 1:m, 1:k ) = C( 1:m, 1:k ) - W( 1:m, 1:k ) 201: * 202: DO 60 J = 1, K 203: DO 50 I = 1, M 204: C( I, J ) = C( I, J ) - WORK( I, J ) 205: 50 CONTINUE 206: 60 CONTINUE 207: * 208: * C( 1:m, n-l+1:n ) = C( 1:m, n-l+1:n ) - ... 209: * W( 1:m, 1:k ) * V( 1:k, 1:l ) 210: * 211: IF( L.GT.0 ) 212: $ CALL DGEMM( 'No transpose', 'No transpose', M, L, K, -ONE, 213: $ WORK, LDWORK, V, LDV, ONE, C( 1, N-L+1 ), LDC ) 214: * 215: END IF 216: * 217: RETURN 218: * 219: * End of DLARZB 220: * 221: END