LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
recursive subroutine  zuncsd (JOBU1, JOBU2, JOBV1T, JOBV2T, TRANS, SIGNS, M, P, Q, X11, LDX11, X12, LDX12, X21, LDX21, X22, LDX22, THETA, U1, LDU1, U2, LDU2, V1T, LDV1T, V2T, LDV2T, WORK, LWORK, RWORK, LRWORK, IWORK, INFO) 
ZUNCSD 
recursive subroutine zuncsd  (  character  JOBU1, 
character  JOBU2,  
character  JOBV1T,  
character  JOBV2T,  
character  TRANS,  
character  SIGNS,  
integer  M,  
integer  P,  
integer  Q,  
complex*16, dimension( ldx11, * )  X11,  
integer  LDX11,  
complex*16, dimension( ldx12, * )  X12,  
integer  LDX12,  
complex*16, dimension( ldx21, * )  X21,  
integer  LDX21,  
complex*16, dimension( ldx22, * )  X22,  
integer  LDX22,  
double precision, dimension( * )  THETA,  
complex*16, dimension( ldu1, * )  U1,  
integer  LDU1,  
complex*16, dimension( ldu2, * )  U2,  
integer  LDU2,  
complex*16, dimension( ldv1t, * )  V1T,  
integer  LDV1T,  
complex*16, dimension( ldv2t, * )  V2T,  
integer  LDV2T,  
complex*16, dimension( * )  WORK,  
integer  LWORK,  
double precision, dimension( * )  RWORK,  
integer  LRWORK,  
integer, dimension( * )  IWORK,  
integer  INFO  
) 
ZUNCSD
Download ZUNCSD + dependencies [TGZ] [ZIP] [TXT]ZUNCSD computes the CS decomposition of an MbyM partitioned unitary matrix X: [ I 0 0  0 0 0 ] [ 0 C 0  0 S 0 ] [ X11  X12 ] [ U1  ] [ 0 0 0  0 0 I ] [ V1  ]**H X = [] = [] [] [] . [ X21  X22 ] [  U2 ] [ 0 0 0  I 0 0 ] [  V2 ] [ 0 S 0  0 C 0 ] [ 0 0 I  0 0 0 ] X11 is PbyQ. The unitary matrices U1, U2, V1, and V2 are PbyP, (MP)by(MP), QbyQ, and (MQ)by(MQ), respectively. C and S are RbyR nonnegative diagonal matrices satisfying C^2 + S^2 = I, in which R = MIN(P,MP,Q,MQ).
[in]  JOBU1  JOBU1 is CHARACTER = 'Y': U1 is computed; otherwise: U1 is not computed. 
[in]  JOBU2  JOBU2 is CHARACTER = 'Y': U2 is computed; otherwise: U2 is not computed. 
[in]  JOBV1T  JOBV1T is CHARACTER = 'Y': V1T is computed; otherwise: V1T is not computed. 
[in]  JOBV2T  JOBV2T is CHARACTER = 'Y': V2T is computed; otherwise: V2T is not computed. 
[in]  TRANS  TRANS is CHARACTER = 'T': X, U1, U2, V1T, and V2T are stored in rowmajor order; otherwise: X, U1, U2, V1T, and V2T are stored in column major order. 
[in]  SIGNS  SIGNS is CHARACTER = 'O': The lowerleft block is made nonpositive (the "other" convention); otherwise: The upperright block is made nonpositive (the "default" convention). 
[in]  M  M is INTEGER The number of rows and columns in X. 
[in]  P  P is INTEGER The number of rows in X11 and X12. 0 <= P <= M. 
[in]  Q  Q is INTEGER The number of columns in X11 and X21. 0 <= Q <= M. 
[in,out]  X11  X11 is COMPLEX*16 array, dimension (LDX11,Q) On entry, part of the unitary matrix whose CSD is desired. 
[in]  LDX11  LDX11 is INTEGER The leading dimension of X11. LDX11 >= MAX(1,P). 
[in,out]  X12  X12 is COMPLEX*16 array, dimension (LDX12,MQ) On entry, part of the unitary matrix whose CSD is desired. 
[in]  LDX12  LDX12 is INTEGER The leading dimension of X12. LDX12 >= MAX(1,P). 
[in,out]  X21  X21 is COMPLEX*16 array, dimension (LDX21,Q) On entry, part of the unitary matrix whose CSD is desired. 
[in]  LDX21  LDX21 is INTEGER The leading dimension of X11. LDX21 >= MAX(1,MP). 
[in,out]  X22  X22 is COMPLEX*16 array, dimension (LDX22,MQ) On entry, part of the unitary matrix whose CSD is desired. 
[in]  LDX22  LDX22 is INTEGER The leading dimension of X11. LDX22 >= MAX(1,MP). 
[out]  THETA  THETA is DOUBLE PRECISION array, dimension (R), in which R = MIN(P,MP,Q,MQ). C = DIAG( COS(THETA(1)), ... , COS(THETA(R)) ) and S = DIAG( SIN(THETA(1)), ... , SIN(THETA(R)) ). 
[out]  U1  U1 is COMPLEX*16 array, dimension (P) If JOBU1 = 'Y', U1 contains the PbyP unitary matrix U1. 
[in]  LDU1  LDU1 is INTEGER The leading dimension of U1. If JOBU1 = 'Y', LDU1 >= MAX(1,P). 
[out]  U2  U2 is COMPLEX*16 array, dimension (MP) If JOBU2 = 'Y', U2 contains the (MP)by(MP) unitary matrix U2. 
[in]  LDU2  LDU2 is INTEGER The leading dimension of U2. If JOBU2 = 'Y', LDU2 >= MAX(1,MP). 
[out]  V1T  V1T is COMPLEX*16 array, dimension (Q) If JOBV1T = 'Y', V1T contains the QbyQ matrix unitary matrix V1**H. 
[in]  LDV1T  LDV1T is INTEGER The leading dimension of V1T. If JOBV1T = 'Y', LDV1T >= MAX(1,Q). 
[out]  V2T  V2T is COMPLEX*16 array, dimension (MQ) If JOBV2T = 'Y', V2T contains the (MQ)by(MQ) unitary matrix V2**H. 
[in]  LDV2T  LDV2T is INTEGER The leading dimension of V2T. If JOBV2T = 'Y', LDV2T >= MAX(1,MQ). 
[out]  WORK  WORK is COMPLEX*16 array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK. 
[in]  LWORK  LWORK is INTEGER The dimension of the array WORK. 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. 
[out]  RWORK  RWORK is DOUBLE PRECISION array, dimension MAX(1,LRWORK) On exit, if INFO = 0, RWORK(1) returns the optimal LRWORK. If INFO > 0 on exit, RWORK(2:R) contains the values PHI(1), ..., PHI(R1) that, together with THETA(1), ..., THETA(R), define the matrix in intermediate bidiagonalblock form remaining after nonconvergence. INFO specifies the number of nonzero PHI's. 
[in]  LRWORK  LRWORK is INTEGER The dimension of the array RWORK. If LRWORK = 1, then a workspace query is assumed; the routine only calculates the optimal size of the RWORK array, returns this value as the first entry of the work array, and no error message related to LRWORK is issued by XERBLA. 
[out]  IWORK  IWORK is INTEGER array, dimension (MMIN(P,MP,Q,MQ)) 
[out]  INFO  INFO is INTEGER = 0: successful exit. < 0: if INFO = i, the ith argument had an illegal value. > 0: ZBBCSD did not converge. See the description of RWORK above for details. 
Definition at line 316 of file zuncsd.f.