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[Help-gsl] Usage of gsl_multiroot_function_fdf
From: |
Gerald I. Evenden |
Subject: |
[Help-gsl] Usage of gsl_multiroot_function_fdf |
Date: |
Sat, 1 Nov 2008 22:19:16 -0400 |
User-agent: |
KMail/1.9.9 |
This function gsl_multiroot_function_fdf requires three function entries: the
basic function, the derivative of the function and a sequential call to the
first two.
The operation of *_fdf (last function listed in gsl_multiroot_function_fdf) is
clear in that a sequence of a call to the function followed by a derivative
call guarantees that elements of the computation of the basic function may be
carried over to the derivative call. What is not clear, because of the
independently passed derivative call, is whether it is guarantee that the
basic function will always be called (with the same arguments) before the
derivative funtion. If this sequence were true, it would appear that the
second function (derivative) argument in gsl_multiroot_function_fdf would not
be necessary.
What I am concerned with is: can I depend upon a call to the basic function
prior to a call to the derivative function---each with the same vector x
argument.
Comments appreciated. Thank-you.
PS: Current usage works assuming without carrying over computations but some
speed up should occur if I can use previously computed elements in the
derivatives.
--
The whole religious complexion of the modern world is due
to the absence from Jerusalem of a lunatic asylum.
-- Havelock Ellis (1859-1939) British psychologist
- [Help-gsl] Usage of gsl_multiroot_function_fdf,
Gerald I. Evenden <=