Subroutine */
| 2052 | } /* dgebal_ */ |
| 2053 | |
| 2054 | /* Subroutine */ int dgebd2_(integer *m, integer *n, doublereal *a, integer * |
| 2055 | lda, doublereal *d__, doublereal *e, doublereal *tauq, doublereal * |
| 2056 | taup, doublereal *work, integer *info) |
| 2057 | { |
| 2058 | /* System generated locals */ |
| 2059 | integer a_dim1, a_offset, i__1, i__2, i__3; |
| 2060 | |
| 2061 | /* Local variables */ |
| 2062 | static integer i__; |
| 2063 | extern /* Subroutine */ int dlarf_(char *, integer *, integer *, |
| 2064 | doublereal *, integer *, doublereal *, doublereal *, integer *, |
| 2065 | doublereal *), dlarfg_(integer *, doublereal *, |
| 2066 | doublereal *, integer *, doublereal *), xerbla_(char *, integer *); |
| 2067 | |
| 2068 | |
| 2069 | /* |
| 2070 | -- LAPACK routine (version 3.2) -- |
| 2071 | -- LAPACK is a software package provided by Univ. of Tennessee, -- |
| 2072 | -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
| 2073 | November 2006 |
| 2074 | |
| 2075 | |
| 2076 | Purpose |
| 2077 | ======= |
| 2078 | |
| 2079 | DGEBD2 reduces a real general m by n matrix A to upper or lower |
| 2080 | bidiagonal form B by an orthogonal transformation: Q' * A * P = B. |
| 2081 | |
| 2082 | If m >= n, B is upper bidiagonal; if m < n, B is lower bidiagonal. |
| 2083 | |
| 2084 | Arguments |
| 2085 | ========= |
| 2086 | |
| 2087 | M (input) INTEGER |
| 2088 | The number of rows in the matrix A. M >= 0. |
| 2089 | |
| 2090 | N (input) INTEGER |
| 2091 | The number of columns in the matrix A. N >= 0. |
| 2092 | |
| 2093 | A (input/output) DOUBLE PRECISION array, dimension (LDA,N) |
| 2094 | On entry, the m by n general matrix to be reduced. |
| 2095 | On exit, |
| 2096 | if m >= n, the diagonal and the first superdiagonal are |
| 2097 | overwritten with the upper bidiagonal matrix B; the |
| 2098 | elements below the diagonal, with the array TAUQ, represent |
| 2099 | the orthogonal matrix Q as a product of elementary |
| 2100 | reflectors, and the elements above the first superdiagonal, |
| 2101 | with the array TAUP, represent the orthogonal matrix P as |
| 2102 | a product of elementary reflectors; |
| 2103 | if m < n, the diagonal and the first subdiagonal are |
| 2104 | overwritten with the lower bidiagonal matrix B; the |
| 2105 | elements below the first subdiagonal, with the array TAUQ, |
| 2106 | represent the orthogonal matrix Q as a product of |
| 2107 | elementary reflectors, and the elements above the diagonal, |
| 2108 | with the array TAUP, represent the orthogonal matrix P as |
| 2109 | a product of elementary reflectors. |
| 2110 | See Further Details. |
| 2111 |