version 1.3, 2010/08/06 15:28:52
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version 1.9, 2011/07/22 07:38:14
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SUBROUTINE ZGEQR2( M, N, A, LDA, TAU, WORK, INFO ) |
SUBROUTINE ZGEQR2( M, N, A, LDA, TAU, 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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* |
* |
* Each H(i) has the form |
* Each H(i) has the form |
* |
* |
* H(i) = I - tau * v * v' |
* H(i) = I - tau * v * v**H |
* |
* |
* where tau is a complex scalar, and v is a complex vector with |
* where tau is a complex scalar, and v is a complex vector with |
* v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i), |
* v(1:i-1) = 0 and v(i) = 1; v(i+1:m) is stored on exit in A(i+1:m,i), |
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COMPLEX*16 ALPHA |
COMPLEX*16 ALPHA |
* .. |
* .. |
* .. External Subroutines .. |
* .. External Subroutines .. |
EXTERNAL XERBLA, ZLARF, ZLARFP |
EXTERNAL XERBLA, ZLARF, ZLARFG |
* .. |
* .. |
* .. Intrinsic Functions .. |
* .. Intrinsic Functions .. |
INTRINSIC DCONJG, MAX, MIN |
INTRINSIC DCONJG, MAX, MIN |
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* |
* |
* Generate elementary reflector H(i) to annihilate A(i+1:m,i) |
* Generate elementary reflector H(i) to annihilate A(i+1:m,i) |
* |
* |
CALL ZLARFP( M-I+1, A( I, I ), A( MIN( I+1, M ), I ), 1, |
CALL ZLARFG( M-I+1, A( I, I ), A( MIN( I+1, M ), I ), 1, |
$ TAU( I ) ) |
$ TAU( I ) ) |
IF( I.LT.N ) THEN |
IF( I.LT.N ) THEN |
* |
* |
* Apply H(i)' to A(i:m,i+1:n) from the left |
* Apply H(i)**H to A(i:m,i+1:n) from the left |
* |
* |
ALPHA = A( I, I ) |
ALPHA = A( I, I ) |
A( I, I ) = ONE |
A( I, I ) = ONE |