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Diffstat (limited to 'src/fortran/lapack/zunmrz.f')
| -rw-r--r-- | src/fortran/lapack/zunmrz.f | 296 |
1 files changed, 296 insertions, 0 deletions
diff --git a/src/fortran/lapack/zunmrz.f b/src/fortran/lapack/zunmrz.f new file mode 100644 index 0000000..c763705 --- /dev/null +++ b/src/fortran/lapack/zunmrz.f @@ -0,0 +1,296 @@ + SUBROUTINE ZUNMRZ( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, + $ WORK, LWORK, INFO ) +* +* -- LAPACK routine (version 3.1) -- +* Univ. of Tennessee, Univ. of California Berkeley and NAG Ltd.. +* November 2006 +* +* .. Scalar Arguments .. + CHARACTER SIDE, TRANS + INTEGER INFO, K, L, LDA, LDC, LWORK, M, N +* .. +* .. Array Arguments .. + COMPLEX*16 A( LDA, * ), C( LDC, * ), TAU( * ), WORK( * ) +* .. +* +* Purpose +* ======= +* +* ZUNMRZ overwrites the general complex M-by-N matrix C with +* +* SIDE = 'L' SIDE = 'R' +* TRANS = 'N': Q * C C * Q +* TRANS = 'C': Q**H * C C * Q**H +* +* where Q is a complex unitary matrix defined as the product of k +* elementary reflectors +* +* Q = H(1) H(2) . . . H(k) +* +* as returned by ZTZRZF. Q is of order M if SIDE = 'L' and of order N +* if SIDE = 'R'. +* +* Arguments +* ========= +* +* SIDE (input) CHARACTER*1 +* = 'L': apply Q or Q**H from the Left; +* = 'R': apply Q or Q**H from the Right. +* +* TRANS (input) CHARACTER*1 +* = 'N': No transpose, apply Q; +* = 'C': Conjugate transpose, apply Q**H. +* +* M (input) INTEGER +* The number of rows of the matrix C. M >= 0. +* +* N (input) INTEGER +* The number of columns of the matrix C. N >= 0. +* +* K (input) INTEGER +* The number of elementary reflectors whose product defines +* the matrix Q. +* If SIDE = 'L', M >= K >= 0; +* if SIDE = 'R', N >= K >= 0. +* +* L (input) INTEGER +* The number of columns of the matrix A containing +* the meaningful part of the Householder reflectors. +* If SIDE = 'L', M >= L >= 0, if SIDE = 'R', N >= L >= 0. +* +* A (input) COMPLEX*16 array, dimension +* (LDA,M) if SIDE = 'L', +* (LDA,N) if SIDE = 'R' +* The i-th row must contain the vector which defines the +* elementary reflector H(i), for i = 1,2,...,k, as returned by +* ZTZRZF in the last k rows of its array argument A. +* A is modified by the routine but restored on exit. +* +* LDA (input) INTEGER +* The leading dimension of the array A. LDA >= max(1,K). +* +* TAU (input) COMPLEX*16 array, dimension (K) +* TAU(i) must contain the scalar factor of the elementary +* reflector H(i), as returned by ZTZRZF. +* +* C (input/output) COMPLEX*16 array, dimension (LDC,N) +* On entry, the M-by-N matrix C. +* On exit, C is overwritten by Q*C or Q**H*C or C*Q**H or C*Q. +* +* LDC (input) INTEGER +* The leading dimension of the array C. LDC >= max(1,M). +* +* WORK (workspace/output) COMPLEX*16 array, dimension (MAX(1,LWORK)) +* On exit, if INFO = 0, WORK(1) returns the optimal LWORK. +* +* LWORK (input) INTEGER +* The dimension of the array WORK. +* If SIDE = 'L', LWORK >= max(1,N); +* if SIDE = 'R', LWORK >= max(1,M). +* For optimum performance LWORK >= N*NB if SIDE = 'L', and +* LWORK >= M*NB if SIDE = 'R', where NB is the optimal +* blocksize. +* +* If LWORK = -1, then a workspace query is assumed; the routine +* only calculates the optimal size of the WORK array, returns +* this value as the first entry of the WORK array, and no error +* message related to LWORK is issued by XERBLA. +* +* INFO (output) INTEGER +* = 0: successful exit +* < 0: if INFO = -i, the i-th argument had an illegal value +* +* Further Details +* =============== +* +* Based on contributions by +* A. Petitet, Computer Science Dept., Univ. of Tenn., Knoxville, USA +* +* ===================================================================== +* +* .. Parameters .. + INTEGER NBMAX, LDT + PARAMETER ( NBMAX = 64, LDT = NBMAX+1 ) +* .. +* .. Local Scalars .. + LOGICAL LEFT, LQUERY, NOTRAN + CHARACTER TRANST + INTEGER I, I1, I2, I3, IB, IC, IINFO, IWS, JA, JC, + $ LDWORK, LWKOPT, MI, NB, NBMIN, NI, NQ, NW +* .. +* .. Local Arrays .. + COMPLEX*16 T( LDT, NBMAX ) +* .. +* .. External Functions .. + LOGICAL LSAME + INTEGER ILAENV + EXTERNAL LSAME, ILAENV +* .. +* .. External Subroutines .. + EXTERNAL XERBLA, ZLARZB, ZLARZT, ZUNMR3 +* .. +* .. Intrinsic Functions .. + INTRINSIC MAX, MIN +* .. +* .. Executable Statements .. +* +* Test the input arguments +* + INFO = 0 + LEFT = LSAME( SIDE, 'L' ) + NOTRAN = LSAME( TRANS, 'N' ) + LQUERY = ( LWORK.EQ.-1 ) +* +* NQ is the order of Q and NW is the minimum dimension of WORK +* + IF( LEFT ) THEN + NQ = M + NW = MAX( 1, N ) + ELSE + NQ = N + NW = MAX( 1, M ) + END IF + IF( .NOT.LEFT .AND. .NOT.LSAME( SIDE, 'R' ) ) THEN + INFO = -1 + ELSE IF( .NOT.NOTRAN .AND. .NOT.LSAME( TRANS, 'C' ) ) THEN + INFO = -2 + ELSE IF( M.LT.0 ) THEN + INFO = -3 + ELSE IF( N.LT.0 ) THEN + INFO = -4 + ELSE IF( K.LT.0 .OR. K.GT.NQ ) THEN + INFO = -5 + ELSE IF( L.LT.0 .OR. ( LEFT .AND. ( L.GT.M ) ) .OR. + $ ( .NOT.LEFT .AND. ( L.GT.N ) ) ) THEN + INFO = -6 + ELSE IF( LDA.LT.MAX( 1, K ) ) THEN + INFO = -8 + ELSE IF( LDC.LT.MAX( 1, M ) ) THEN + INFO = -11 + END IF +* + IF( INFO.EQ.0 ) THEN + IF( M.EQ.0 .OR. N.EQ.0 ) THEN + LWKOPT = 1 +* +* Determine the block size. NB may be at most NBMAX, where +* NBMAX is used to define the local array T. +* + NB = MIN( NBMAX, ILAENV( 1, 'ZUNMRQ', SIDE // TRANS, M, N, + $ K, -1 ) ) + LWKOPT = NW*NB + END IF + WORK( 1 ) = LWKOPT +* + IF( LWORK.LT.MAX( 1, NW ) .AND. .NOT.LQUERY ) THEN + INFO = -13 + END IF + END IF +* + IF( INFO.NE.0 ) THEN + CALL XERBLA( 'ZUNMRZ', -INFO ) + RETURN + ELSE IF( LQUERY ) THEN + RETURN + END IF +* +* Quick return if possible +* + IF( M.EQ.0 .OR. N.EQ.0 ) THEN + RETURN + END IF +* +* Determine the block size. NB may be at most NBMAX, where NBMAX +* is used to define the local array T. +* + NB = MIN( NBMAX, ILAENV( 1, 'ZUNMRQ', SIDE // TRANS, M, N, K, + $ -1 ) ) + NBMIN = 2 + LDWORK = NW + IF( NB.GT.1 .AND. NB.LT.K ) THEN + IWS = NW*NB + IF( LWORK.LT.IWS ) THEN + NB = LWORK / LDWORK + NBMIN = MAX( 2, ILAENV( 2, 'ZUNMRQ', SIDE // TRANS, M, N, K, + $ -1 ) ) + END IF + ELSE + IWS = NW + END IF +* + IF( NB.LT.NBMIN .OR. NB.GE.K ) THEN +* +* Use unblocked code +* + CALL ZUNMR3( SIDE, TRANS, M, N, K, L, A, LDA, TAU, C, LDC, + $ WORK, IINFO ) + ELSE +* +* Use blocked code +* + IF( ( LEFT .AND. .NOT.NOTRAN ) .OR. + $ ( .NOT.LEFT .AND. NOTRAN ) ) THEN + I1 = 1 + I2 = K + I3 = NB + ELSE + I1 = ( ( K-1 ) / NB )*NB + 1 + I2 = 1 + I3 = -NB + END IF +* + IF( LEFT ) THEN + NI = N + JC = 1 + JA = M - L + 1 + ELSE + MI = M + IC = 1 + JA = N - L + 1 + END IF +* + IF( NOTRAN ) THEN + TRANST = 'C' + ELSE + TRANST = 'N' + END IF +* + DO 10 I = I1, I2, I3 + IB = MIN( NB, K-I+1 ) +* +* Form the triangular factor of the block reflector +* H = H(i+ib-1) . . . H(i+1) H(i) +* + CALL ZLARZT( 'Backward', 'Rowwise', L, IB, A( I, JA ), LDA, + $ TAU( I ), T, LDT ) +* + IF( LEFT ) THEN +* +* H or H' is applied to C(i:m,1:n) +* + MI = M - I + 1 + IC = I + ELSE +* +* H or H' is applied to C(1:m,i:n) +* + NI = N - I + 1 + JC = I + END IF +* +* Apply H or H' +* + CALL ZLARZB( SIDE, TRANST, 'Backward', 'Rowwise', MI, NI, + $ IB, L, A( I, JA ), LDA, T, LDT, C( IC, JC ), + $ LDC, WORK, LDWORK ) + 10 CONTINUE +* + END IF +* + WORK( 1 ) = LWKOPT +* + RETURN +* +* End of ZUNMRZ +* + END |