1CUPMTR(1)                LAPACK routine (version 3.2)                CUPMTR(1)
2
3
4

NAME

6       CUPMTR  -  overwrites the general complex M-by-N matrix C with   SIDE =
7       'L' SIDE = 'R' TRANS = 'N'
8

SYNOPSIS

10       SUBROUTINE CUPMTR( SIDE, UPLO, TRANS, M, N, AP, TAU, C, LDC, WORK, INFO
11                          )
12
13           CHARACTER      SIDE, TRANS, UPLO
14
15           INTEGER        INFO, LDC, M, N
16
17           COMPLEX        AP( * ), C( LDC, * ), TAU( * ), WORK( * )
18

PURPOSE

20       CUPMTR overwrites the general complex M-by-N matrix C with TRANS = 'C':
21       Q**H * C       C * Q**H
22       where Q is a complex unitary matrix of order nq, with nq = m if SIDE  =
23       'L'  and nq = n if SIDE = 'R'. Q is defined as the product of nq-1 ele‐
24       mentary reflectors, as returned by CHPTRD using packed storage:
25       if UPLO = 'U', Q = H(nq-1) . . . H(2) H(1);
26       if UPLO = 'L', Q = H(1) H(2) . . . H(nq-1).
27

ARGUMENTS

29       SIDE    (input) CHARACTER*1
30               = 'L': apply Q or Q**H from the Left;
31               = 'R': apply Q or Q**H from the Right.
32
33       UPLO    (input) CHARACTER*1
34               = 'U': Upper triangular packed storage used in previous call to
35               CHPTRD; = 'L': Lower triangular packed storage used in previous
36               call to CHPTRD.
37
38       TRANS   (input) CHARACTER*1
39               = 'N':  No transpose, apply Q;
40               = 'C':  Conjugate transpose, apply Q**H.
41
42       M       (input) INTEGER
43               The number of rows of the matrix C. M >= 0.
44
45       N       (input) INTEGER
46               The number of columns of the matrix C. N >= 0.
47
48       AP      (input) COMPLEX array, dimension
49               (M*(M+1)/2) if SIDE = 'L' (N*(N+1)/2) if SIDE = 'R' The vectors
50               which  define the elementary reflectors, as returned by CHPTRD.
51               AP is modified by the routine but restored on exit.
52
53       TAU     (input) COMPLEX array, dimension (M-1) if SIDE = 'L'
54               or (N-1) if SIDE = 'R' TAU(i) must contain the scalar factor of
55               the elementary reflector H(i), as returned by CHPTRD.
56
57       C       (input/output) COMPLEX array, dimension (LDC,N)
58               On  entry,  the  M-by-N matrix C.  On exit, C is overwritten by
59               Q*C or Q**H*C or C*Q**H or C*Q.
60
61       LDC     (input) INTEGER
62               The leading dimension of the array C. LDC >= max(1,M).
63
64       WORK    (workspace) COMPLEX array, dimension
65               (N) if SIDE = 'L' (M) if SIDE = 'R'
66
67       INFO    (output) INTEGER
68               = 0:  successful exit
69               < 0:  if INFO = -i, the i-th argument had an illegal value
70
71
72
73 LAPACK routine (version 3.2)    November 2008                       CUPMTR(1)
Impressum