version 1.7, 2010/12/21 13:53:52
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version 1.8, 2011/11/21 20:43:17
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*> \brief \b ZLASSQ |
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* |
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* =========== DOCUMENTATION =========== |
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* |
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* Online html documentation available at |
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* http://www.netlib.org/lapack/explore-html/ |
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* |
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*> \htmlonly |
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*> Download ZLASSQ + dependencies |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.tgz?format=tgz&filename=/lapack/lapack_routine/zlassq.f"> |
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*> [TGZ]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.zip?format=zip&filename=/lapack/lapack_routine/zlassq.f"> |
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*> [ZIP]</a> |
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*> <a href="http://www.netlib.org/cgi-bin/netlibfiles.txt?format=txt&filename=/lapack/lapack_routine/zlassq.f"> |
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*> [TXT]</a> |
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*> \endhtmlonly |
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* |
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* Definition: |
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* =========== |
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* |
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* SUBROUTINE ZLASSQ( N, X, INCX, SCALE, SUMSQ ) |
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* |
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* .. Scalar Arguments .. |
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* INTEGER INCX, N |
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* DOUBLE PRECISION SCALE, SUMSQ |
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* .. |
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* .. Array Arguments .. |
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* COMPLEX*16 X( * ) |
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* .. |
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* |
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* |
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*> \par Purpose: |
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* ============= |
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*> |
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*> \verbatim |
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*> |
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*> ZLASSQ returns the values scl and ssq such that |
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*> |
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*> ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq, |
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*> |
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*> where x( i ) = abs( X( 1 + ( i - 1 )*INCX ) ). The value of sumsq is |
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*> assumed to be at least unity and the value of ssq will then satisfy |
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*> |
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*> 1.0 .le. ssq .le. ( sumsq + 2*n ). |
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*> |
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*> scale is assumed to be non-negative and scl returns the value |
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*> |
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*> scl = max( scale, abs( real( x( i ) ) ), abs( aimag( x( i ) ) ) ), |
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*> i |
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*> |
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*> scale and sumsq must be supplied in SCALE and SUMSQ respectively. |
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*> SCALE and SUMSQ are overwritten by scl and ssq respectively. |
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*> |
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*> The routine makes only one pass through the vector X. |
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*> \endverbatim |
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* |
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* Arguments: |
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* ========== |
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* |
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*> \param[in] N |
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*> \verbatim |
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*> N is INTEGER |
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*> The number of elements to be used from the vector X. |
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*> \endverbatim |
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*> |
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*> \param[in] X |
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*> \verbatim |
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*> X is COMPLEX*16 array, dimension (N) |
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*> The vector x as described above. |
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*> x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n. |
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*> \endverbatim |
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*> |
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*> \param[in] INCX |
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*> \verbatim |
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*> INCX is INTEGER |
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*> The increment between successive values of the vector X. |
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*> INCX > 0. |
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*> \endverbatim |
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*> |
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*> \param[in,out] SCALE |
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*> \verbatim |
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*> SCALE is DOUBLE PRECISION |
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*> On entry, the value scale in the equation above. |
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*> On exit, SCALE is overwritten with the value scl . |
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*> \endverbatim |
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*> |
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*> \param[in,out] SUMSQ |
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*> \verbatim |
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*> SUMSQ is DOUBLE PRECISION |
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*> On entry, the value sumsq in the equation above. |
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*> On exit, SUMSQ is overwritten with the value ssq . |
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*> \endverbatim |
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* |
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* Authors: |
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* ======== |
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* |
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*> \author Univ. of Tennessee |
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*> \author Univ. of California Berkeley |
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*> \author Univ. of Colorado Denver |
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*> \author NAG Ltd. |
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* |
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*> \date November 2011 |
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* |
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*> \ingroup complex16OTHERauxiliary |
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* |
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* ===================================================================== |
SUBROUTINE ZLASSQ( N, X, INCX, SCALE, SUMSQ ) |
SUBROUTINE ZLASSQ( N, X, INCX, SCALE, SUMSQ ) |
* |
* |
* -- LAPACK auxiliary routine (version 3.2) -- |
* -- LAPACK auxiliary routine (version 3.4.0) -- |
* -- 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 |
* November 2011 |
* |
* |
* .. Scalar Arguments .. |
* .. Scalar Arguments .. |
INTEGER INCX, N |
INTEGER INCX, N |
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COMPLEX*16 X( * ) |
COMPLEX*16 X( * ) |
* .. |
* .. |
* |
* |
* Purpose |
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* ======= |
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* |
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* ZLASSQ returns the values scl and ssq such that |
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* |
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* ( scl**2 )*ssq = x( 1 )**2 +...+ x( n )**2 + ( scale**2 )*sumsq, |
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* |
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* where x( i ) = abs( X( 1 + ( i - 1 )*INCX ) ). The value of sumsq is |
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* assumed to be at least unity and the value of ssq will then satisfy |
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* |
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* 1.0 .le. ssq .le. ( sumsq + 2*n ). |
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* |
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* scale is assumed to be non-negative and scl returns the value |
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* |
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* scl = max( scale, abs( real( x( i ) ) ), abs( aimag( x( i ) ) ) ), |
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* i |
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* |
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* scale and sumsq must be supplied in SCALE and SUMSQ respectively. |
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* SCALE and SUMSQ are overwritten by scl and ssq respectively. |
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* |
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* The routine makes only one pass through the vector X. |
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* |
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* Arguments |
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* ========= |
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* |
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* N (input) INTEGER |
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* The number of elements to be used from the vector X. |
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* |
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* X (input) COMPLEX*16 array, dimension (N) |
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* The vector x as described above. |
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* x( i ) = X( 1 + ( i - 1 )*INCX ), 1 <= i <= n. |
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* |
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* INCX (input) INTEGER |
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* The increment between successive values of the vector X. |
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* INCX > 0. |
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* |
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* SCALE (input/output) DOUBLE PRECISION |
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* On entry, the value scale in the equation above. |
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* On exit, SCALE is overwritten with the value scl . |
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* |
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* SUMSQ (input/output) DOUBLE PRECISION |
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* On entry, the value sumsq in the equation above. |
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* On exit, SUMSQ is overwritten with the value ssq . |
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* |
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* ===================================================================== |
* ===================================================================== |
* |
* |
* .. Parameters .. |
* .. Parameters .. |