version 1.6, 2010/08/13 21:03:43
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version 1.8, 2011/07/22 07:38:04
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SUBROUTINE DGEBD2( M, N, A, LDA, D, E, TAUQ, TAUP, WORK, INFO ) |
SUBROUTINE DGEBD2( M, N, A, LDA, D, E, TAUQ, TAUP, WORK, INFO ) |
* |
* |
* -- LAPACK routine (version 3.2) -- |
* -- LAPACK routine (version 3.3.1) -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- LAPACK is a software package provided by Univ. of Tennessee, -- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..-- |
* November 2006 |
* -- April 2011 -- |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER INFO, LDA, M, N |
INTEGER INFO, LDA, M, N |
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* ======= |
* ======= |
* |
* |
* DGEBD2 reduces a real general m by n matrix A to upper or lower |
* DGEBD2 reduces a real general m by n matrix A to upper or lower |
* bidiagonal form B by an orthogonal transformation: Q' * A * P = B. |
* bidiagonal form B by an orthogonal transformation: Q**T * A * P = B. |
* |
* |
* If m >= n, B is upper bidiagonal; if m < n, B is lower bidiagonal. |
* If m >= n, B is upper bidiagonal; if m < n, B is lower bidiagonal. |
* |
* |
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* |
* |
* Each H(i) and G(i) has the form: |
* Each H(i) and G(i) has the form: |
* |
* |
* H(i) = I - tauq * v * v' and G(i) = I - taup * u * u' |
* H(i) = I - tauq * v * v**T and G(i) = I - taup * u * u**T |
* |
* |
* where tauq and taup are real scalars, and v and u are real vectors; |
* where tauq and taup are real scalars, and v and u are real vectors; |
* v(1:i-1) = 0, v(i) = 1, and v(i+1:m) is stored on exit in A(i+1:m,i); |
* v(1:i-1) = 0, v(i) = 1, and v(i+1:m) is stored on exit in A(i+1:m,i); |
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* |
* |
* Each H(i) and G(i) has the form: |
* Each H(i) and G(i) has the form: |
* |
* |
* H(i) = I - tauq * v * v' and G(i) = I - taup * u * u' |
* H(i) = I - tauq * v * v**T and G(i) = I - taup * u * u**T |
* |
* |
* where tauq and taup are real scalars, and v and u are real vectors; |
* where tauq and taup are real scalars, and v and u are real vectors; |
* v(1:i) = 0, v(i+1) = 1, and v(i+2:m) is stored on exit in A(i+2:m,i); |
* v(1:i) = 0, v(i+1) = 1, and v(i+2:m) is stored on exit in A(i+2:m,i); |