# ctpmlqt.f man page

ctpmlqt.f

## Synopsis

### Functions/Subroutines

subroutine ctpmlqt (SIDE, TRANS, M, N, K, L, MB, V, LDV, T, LDT, A, LDA, B, LDB, WORK, INFO)

## Function/Subroutine Documentation

### subroutine ctpmlqt (character SIDE, character TRANS, integer M, integer N, integer K, integer L, integer MB, complex, dimension( ldv, * ) V, integer LDV, complex, dimension( ldt, * ) T, integer LDT, complex, dimension( lda, * ) A, integer LDA, complex, dimension( ldb, * ) B, integer LDB, complex, dimension( * ) WORK, integer INFO)

Purpose:

CTPMLQT applies a complex orthogonal matrix Q obtained from a 'triangular-pentagonal' complex block reflector H to a general complex matrix C, which consists of two blocks A and B.

Parameters:

SIDE

```          SIDE is CHARACTER*1
= 'L': apply Q or Q**H from the Left;
= 'R': apply Q or Q**H from the Right.```

TRANS

```          TRANS is CHARACTER*1
= 'N':  No transpose, apply Q;
= 'C':  Transpose, apply Q**H.```

M

```          M is INTEGER
The number of rows of the matrix B. M >= 0.```

N

```          N is INTEGER
The number of columns of the matrix B. N >= 0.```

K

```          K is INTEGER
The number of elementary reflectors whose product defines
the matrix Q.```

L

```          L is INTEGER
The order of the trapezoidal part of V.
K >= L >= 0.  See Further Details.```

MB

```          MB is INTEGER
The block size used for the storage of T.  K >= MB >= 1.
This must be the same value of MB used to generate T
in DTPLQT.```

V

```          V is COMPLEX array, dimension (LDA,K)
The i-th row must contain the vector which defines the
elementary reflector H(i), for i = 1,2,...,k, as returned by
DTPLQT in B.  See Further Details.```

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).```

T

```          T is COMPLEX array, dimension (LDT,K)
The upper triangular factors of the block reflectors
as returned by DTPLQT, stored as a MB-by-K matrix.```

LDT

```          LDT is INTEGER
The leading dimension of the array T.  LDT >= MB.```

A

```          A is COMPLEX array, dimension
(LDA,N) if SIDE = 'L' or
(LDA,K) if SIDE = 'R'
On entry, the K-by-N or M-by-K matrix A.
On exit, A is overwritten by the corresponding block of
Q*C or Q**H*C or C*Q or C*Q**H.  See Further Details.```

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).```

B

```          B is COMPLEX array, dimension (LDB,N)
On entry, the M-by-N matrix B.
On exit, B is overwritten by the corresponding block of
Q*C or Q**H*C or C*Q or C*Q**H.  See Further Details.```

LDB

```          LDB is INTEGER
The leading dimension of the array B.
LDB >= max(1,M).```

WORK

```          WORK is COMPLEX array. The dimension of WORK is
N*MB if SIDE = 'L', or  M*MB if SIDE = 'R'.```

INFO

```          INFO is INTEGER
= 0:  successful exit
< 0:  if INFO = -i, the i-th argument had an illegal value```
Author:

Univ. of Tennessee

Univ. of California Berkeley

NAG Ltd.

Date:

June 2017

Further Details:

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 lower trapezoidal, consisting of the first L rows of a K-by-K upper triangular matrix. If L=K, V2 is lower triangular; if L=0, there is no trapezoidal block, hence V = V1 is rectangular.

If SIDE = 'L': C = [A] where A is K-by-N, B is M-by-N and V is K-by-M. [B]

If SIDE = 'R': C = [A B] where A is M-by-K, B is M-by-N and V is K-by-N.

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='C' and SIDE='L', C is on exit replaced with Q**H * C.

If TRANS='N' and SIDE='R', C is on exit replaced with C * Q.

If TRANS='C' and SIDE='R', C is on exit replaced with C * Q**H.

Definition at line 201 of file ctpmlqt.f.

## Author

Generated automatically by Doxygen for LAPACK from the source code.

## Referenced By

The man page ctpmlqt(3) is an alias of ctpmlqt.f(3).

Tue Nov 14 2017 Version 3.8.0 LAPACK