GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
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dlaed6(l) |
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DLAED6 - compute the positive or negative root (closest to the origin) of z(1) z(2) z(3) f(x) = rho + --------- + ---------- + --------- d(1)-x d(2)-x d(3)-x It is assumed that if ORGATI = .true
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SUBROUTINE DLAED6( |
KNITER, ORGATI, RHO, D, Z, FINIT, TAU, INFO ) | ||
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LOGICAL |
ORGATI | ||
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INTEGER |
INFO, KNITER | ||
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DOUBLE |
PRECISION FINIT, RHO, TAU | ||
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DOUBLE |
PRECISION D( 3 ), Z( 3 ) |
DLAED6 computes the positive or negative root (closest to the origin) of z(1) z(2) z(3) f(x) = rho + --------- + ---------- + --------- d(1)-x d(2)-x d(3)-x It is assumed that if ORGATI = .true. the root is between d(2) and d(3); otherwise it is between d(1) and d(2)
This routine will be called by DLAED4 when necessary. In most cases, the root sought is the smallest in magnitude, though it might not be in some extremely rare situations.
KNITER (input) INTEGER
Refer to DLAED4 for its significance.
ORGATI (input) LOGICAL
If ORGATI is true, the needed root is between d(2) and d(3); otherwise it is between d(1) and d(2). See DLAED4 for further details.
RHO (input) DOUBLE PRECISION
Refer to the equation f(x) above.
D (input) DOUBLE PRECISION array, dimension (3)
D satisfies d(1) < d(2) < d(3).
Z (input) DOUBLE PRECISION array, dimension (3)
Each of the elements in z must be positive.
FINIT (input) DOUBLE PRECISION
The value of f at 0. It is more accurate than the one evaluated inside this routine (if someone wants to do so).
TAU (output) DOUBLE PRECISION
The root of the equation f(x).
INFO (output) INTEGER
= 0: successful exit
> 0: if INFO = 1, failure to converge
Based on
contributions by
Ren-Cang Li, Computer Science Division, University of
California
at Berkeley, USA
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dlaed6(l) | |