LAPACK
3.4.2
LAPACK: Linear Algebra PACKage

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Functions/Subroutines  
subroutine  dtpmqrt (SIDE, TRANS, M, N, K, L, NB, V, LDV, T, LDT, A, LDA, B, LDB, WORK, INFO) 
DTPMQRT 
subroutine dtpmqrt  (  character  SIDE, 
character  TRANS,  
integer  M,  
integer  N,  
integer  K,  
integer  L,  
integer  NB,  
double precision, dimension( ldv, * )  V,  
integer  LDV,  
double precision, dimension( ldt, * )  T,  
integer  LDT,  
double precision, dimension( lda, * )  A,  
integer  LDA,  
double precision, dimension( ldb, * )  B,  
integer  LDB,  
double precision, dimension( * )  WORK,  
integer  INFO  
) 
DTPMQRT
Download DTPMQRT + dependencies [TGZ] [ZIP] [TXT]DTPMQRT applies a real orthogonal matrix Q obtained from a "triangularpentagonal" real block reflector H to a general real matrix C, which consists of two blocks A and B.
[in]  SIDE  SIDE is CHARACTER*1 = 'L': apply Q or Q**T from the Left; = 'R': apply Q or Q**T from the Right. 
[in]  TRANS  TRANS is CHARACTER*1 = 'N': No transpose, apply Q; = 'C': Transpose, apply Q**T. 
[in]  M  M is INTEGER The number of rows of the matrix B. M >= 0. 
[in]  N  N is INTEGER The number of columns of the matrix B. N >= 0. 
[in]  K  K is INTEGER The number of elementary reflectors whose product defines the matrix Q. 
[in]  L  L is INTEGER The order of the trapezoidal part of V. K >= L >= 0. See Further Details. 
[in]  NB  NB is INTEGER The block size used for the storage of T. K >= NB >= 1. This must be the same value of NB used to generate T in CTPQRT. 
[in]  V  V is DOUBLE PRECISION array, dimension (LDA,K) The ith column must contain the vector which defines the elementary reflector H(i), for i = 1,2,...,k, as returned by CTPQRT in B. See Further Details. 
[in]  LDV  LDV is INTEGER The leading dimension of the array V. If SIDE = 'L', LDV >= max(1,M); if SIDE = 'R', LDV >= max(1,N). 
[in]  T  T is DOUBLE PRECISION array, dimension (LDT,K) The upper triangular factors of the block reflectors as returned by CTPQRT, stored as a NBbyK matrix. 
[in]  LDT  LDT is INTEGER The leading dimension of the array T. LDT >= NB. 
[in,out]  A  A is DOUBLE PRECISION array, dimension (LDA,N) if SIDE = 'L' or (LDA,K) if SIDE = 'R' On entry, the KbyN or MbyK matrix A. On exit, A is overwritten by the corresponding block of Q*C or Q**T*C or C*Q or C*Q**T. See Further Details. 
[in]  LDA  LDA is INTEGER The leading dimension of the array A. If SIDE = 'L', LDC >= max(1,K); If SIDE = 'R', LDC >= max(1,M). 
[in,out]  B  B is DOUBLE PRECISION array, dimension (LDB,N) On entry, the MbyN matrix B. On exit, B is overwritten by the corresponding block of Q*C or Q**T*C or C*Q or C*Q**T. See Further Details. 
[in]  LDB  LDB is INTEGER The leading dimension of the array B. LDB >= max(1,M). 
[out]  WORK  WORK is DOUBLE PRECISION array. The dimension of WORK is N*NB if SIDE = 'L', or M*NB if SIDE = 'R'. 
[out]  INFO  INFO is INTEGER = 0: successful exit < 0: if INFO = i, the ith argument had an illegal value 
The columns of the pentagonal matrix V contain the elementary reflectors H(1), H(2), ..., H(K); V is composed of a rectangular block V1 and a trapezoidal block V2: V = [V1] [V2]. The size of the trapezoidal block V2 is determined by the parameter L, where 0 <= L <= K; V2 is upper trapezoidal, consisting of the first L rows of a KbyK upper triangular matrix. If L=K, V2 is upper triangular; if L=0, there is no trapezoidal block, hence V = V1 is rectangular. If SIDE = 'L': C = [A] where A is KbyN, B is MbyN and V is MbyK. [B] If SIDE = 'R': C = [A B] where A is MbyK, B is MbyN and V is NbyK. The real orthogonal matrix Q is formed from V and T. If TRANS='N' and SIDE='L', C is on exit replaced with Q * C. If TRANS='T' and SIDE='L', C is on exit replaced with Q**T * C. If TRANS='N' and SIDE='R', C is on exit replaced with C * Q. If TRANS='T' and SIDE='R', C is on exit replaced with C * Q**T.
Definition at line 216 of file dtpmqrt.f.