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DORMBRRun Method

Purpose ======= If VECT = 'Q', DORMBR overwrites the general real M-by-N matrix C with SIDE = 'L' SIDE = 'R' TRANS = 'N': Q * C C * Q TRANS = 'T': Q**T * C C * Q**T If VECT = 'P', DORMBR overwrites the general real M-by-N matrix C with SIDE = 'L' SIDE = 'R' TRANS = 'N': P * C C * P TRANS = 'T': P**T * C C * P**T Here Q and P**T are the orthogonal matrices determined by DGEBRD when reducing a real matrix A to bidiagonal form: A = Q * B * P**T. Q and P**T are defined as products of elementary reflectors H(i) and G(i) respectively. Let nq = m if SIDE = 'L' and nq = n if SIDE = 'R'. Thus nq is the order of the orthogonal matrix Q or P**T that is applied. If VECT = 'Q', A is assumed to have been an NQ-by-K matrix: if nq .GE. k, Q = H(1) H(2) . . . H(k); if nq .LT. k, Q = H(1) H(2) . . . H(nq-1). If VECT = 'P', A is assumed to have been a K-by-NQ matrix: if k .LT. nq, P = G(1) G(2) . . . G(k); if k .GE. nq, P = G(1) G(2) . . . G(nq-1).

Namespace: DotNumerics.LinearAlgebra.CSLapack
Assembly: DWSIM.MathOps.DotNumerics (in DWSIM.MathOps.DotNumerics.dll) Version: 1.0.0.0 (1.0.0.0)
Syntax
Copy
public void Run(
	string VECT,
	string SIDE,
	string TRANS,
	int M,
	int N,
	int K,
	ref double[] A,
	int offset_a,
	int LDA,
	double[] TAU,
	int offset_tau,
	ref double[] C,
	int offset_c,
	int LDC,
	ref double[] WORK,
	int offset_work,
	int LWORK,
	ref int INFO
)
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Parameters

VECT  String
(input) CHARACTER*1 = 'Q': apply Q or Q**T; = 'P': apply P or P**T.
SIDE  String
(input) CHARACTER*1 = 'L': apply Q, Q**T, P or P**T from the Left; = 'R': apply Q, Q**T, P or P**T from the Right.
TRANS  String
(input) CHARACTER*1 = 'N': No transpose, apply Q or P; = 'T': Transpose, apply Q**T or P**T.
M  Int32
(input) INTEGER The number of rows of the matrix C. M .GE. 0.
N  Int32
(input) INTEGER The number of columns of the matrix C. N .GE. 0.
K  Int32
(input) INTEGER If VECT = 'Q', the number of columns in the original matrix reduced by DGEBRD. If VECT = 'P', the number of rows in the original matrix reduced by DGEBRD. K .GE. 0.
A  Double
(input) DOUBLE PRECISION array, dimension (LDA,min(nq,K)) if VECT = 'Q' (LDA,nq) if VECT = 'P' The vectors which define the elementary reflectors H(i) and G(i), whose products determine the matrices Q and P, as returned by DGEBRD.
offset_a  Int32
 
LDA  Int32
(input) INTEGER The leading dimension of the array A. If VECT = 'Q', LDA .GE. max(1,nq); if VECT = 'P', LDA .GE. max(1,min(nq,K)).
TAU  Double
(input) DOUBLE PRECISION array, dimension (min(nq,K)) TAU(i) must contain the scalar factor of the elementary reflector H(i) or G(i) which determines Q or P, as returned by DGEBRD in the array argument TAUQ or TAUP.
offset_tau  Int32
 
C  Double
(input/output) DOUBLE PRECISION array, dimension (LDC,N) On entry, the M-by-N matrix C. On exit, C is overwritten by Q*C or Q**T*C or C*Q**T or C*Q or P*C or P**T*C or C*P or C*P**T.
offset_c  Int32
 
LDC  Int32
(input) INTEGER The leading dimension of the array C. LDC .GE. max(1,M).
WORK  Double
(workspace/output) DOUBLE PRECISION array, dimension (MAX(1,LWORK)) On exit, if INFO = 0, WORK(1) returns the optimal LWORK.
offset_work  Int32
 
LWORK  Int32
(input) INTEGER The dimension of the array WORK. If SIDE = 'L', LWORK .GE. max(1,N); if SIDE = 'R', LWORK .GE. max(1,M). For optimum performance LWORK .GE. N*NB if SIDE = 'L', and LWORK .GE. 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  Int32
(output) INTEGER = 0: successful exit .LT. 0: if INFO = -i, the i-th argument had an illegal value
See Also