1DOPGTR(1)                LAPACK routine (version 3.2)                DOPGTR(1)
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NAME

6       DOPGTR  -  generates a real orthogonal matrix Q which is defined as the
7       product of n-1 elementary reflectors H(i) of order n,  as  returned  by
8       DSPTRD using packed storage
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SYNOPSIS

11       SUBROUTINE DOPGTR( UPLO, N, AP, TAU, Q, LDQ, WORK, INFO )
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13           CHARACTER      UPLO
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15           INTEGER        INFO, LDQ, N
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17           DOUBLE         PRECISION AP( * ), Q( LDQ, * ), TAU( * ), WORK( * )
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PURPOSE

20       DOPGTR  generates  a  real  orthogonal matrix Q which is defined as the
21       product of n-1 elementary reflectors H(i) of order n,  as  returned  by
22       DSPTRD using packed storage: if UPLO = 'U', Q = H(n-1) . . . H(2) H(1),
23       if UPLO = 'L', Q = H(1) H(2) . . . H(n-1).
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ARGUMENTS

26       UPLO    (input) CHARACTER*1
27               = 'U': Upper triangular packed storage used in previous call to
28               DSPTRD; = 'L': Lower triangular packed storage used in previous
29               call to DSPTRD.
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31       N       (input) INTEGER
32               The order of the matrix Q. N >= 0.
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34       AP      (input) DOUBLE PRECISION array, dimension (N*(N+1)/2)
35               The vectors which define the elementary reflectors, as returned
36               by DSPTRD.
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38       TAU     (input) DOUBLE PRECISION array, dimension (N-1)
39               TAU(i) must contain the scalar factor of the elementary reflec‐
40               tor H(i), as returned by DSPTRD.
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42       Q       (output) DOUBLE PRECISION array, dimension (LDQ,N)
43               The N-by-N orthogonal matrix Q.
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45       LDQ     (input) INTEGER
46               The leading dimension of the array Q. LDQ >= max(1,N).
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48       WORK    (workspace) DOUBLE PRECISION array, dimension (N-1)
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50       INFO    (output) INTEGER
51               = 0:  successful exit
52               < 0:  if INFO = -i, the i-th argument had an illegal value
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56 LAPACK routine (version 3.2)    November 2008                       DOPGTR(1)
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