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[Help-gsl] Problem with gsl_root_fdfsolver_newton (corrected)


From: Clemens Prestele
Subject: [Help-gsl] Problem with gsl_root_fdfsolver_newton (corrected)
Date: Wed, 19 Oct 2005 23:57:52 +0200 (CEST)

.
.
Dear Ladies and Gentlemen.

I would be very grateful if you could help me overcome the followingproblem 
that I have encountered on the
usage of gsl_root_fdfsolver_newton.

First of all: I am using GSL-1.6. under Windows XP plus Microsoft VisualStudio. 
Net 2003 (Version 7.1.3088). 

I have essentially copied the example from the gsl-ref.pdf documentregarding 
the gsl_root_fdfsolver_newton 
routine, namely I have the following code:

in "main.c" lies: 

#include <stdio.h>
#include <gsl/gsl_errno.h>
#include <gsl/gsl_math.h>
#include <gsl/gsl_roots.h>
#include "demo_fn.h"

int main(void)
{
        int status;
        int iter = 0, max_iter = 100;
        const gsl_root_fdfsolver_type *T;
        gsl_root_fdfsolver *s;
        double x0, x = 5.0, r_expected = sqrt(5.0);
        gsl_function_fdf FDF;
        struct quadratic_params params = {1.0, 0.0,-5.0};
        FDF.f =&quadratic;
        FDF.df =&quadratic_deriv;
        FDF.fdf =&quadratic_fdf;
        FDF.params= &params;
        T =gsl_root_fdfsolver_newton;
        s =gsl_root_fdfsolver_alloc (T);
        gsl_root_fdfsolver_set (s, &FDF, x);
        printf("using %s method\n",
        gsl_root_fdfsolver_name (s));
        printf("%-5s %10s %10s %10s\n",
        "iter", "root", "err","err(est)");
        do
        {
                iter++;
                status =gsl_root_fdfsolver_iterate (s);
                x0 = x;
                x =gsl_root_fdfsolver_root (s);
                status =gsl_root_test_delta (x, x0, 0, 1e-3);
                if (status == GSL_SUCCESS) printf("Converged:\n");
                printf ("%5d%10.7f %+10.7f %10.7f\n",
                iter, x, x -r_expected, x - x0);
        }
        while (status == GSL_CONTINUE &&iter < max_iter);
        return status;
}

and in "demo_fn.h" lies:

struct quadratic_params
{
        double a, b, c;
};

double quadratic(double x, void*params)
{
        struct quadratic_params *p
        =(struct quadratic_params *) params;
        double a = p->a;
        double b = p->b;
        double c = p->c;
        return (a * x + b) * x + c;
}

double quadratic_deriv(double x, void*params)
{
        struct quadratic_params *p
        =(struct quadratic_params *) params;
        double a = p->a;
        double b = p->b;
        double c = p->c;
        return 2.0 * a * x + b;
}

void quadratic_fdf(double x, void*params,double *y,double *dy)
{
        struct quadratic_params *p
        =(struct quadratic_params *) params;
        double a = p->a;
        double b = p->b;
        double c = p->c;
        *y = (a *x + b) * x + c;
        *dy = 2.0* a * x + b;
}

When I compile the above I obtain the following error messages:

------ Build started: Project: Test 0, Configuration: DebugWin32 ------

Linking...
libgsl.a(roots_secant.o) : error LNK2019: unresolved external symbol_finite 
referenced in function _newton_iterate
H:\C\Dokumente und 
Einstellungen\Clemens\EigeneDateien\Diverse\Clemens\Universitaet\C++\Visual C++ 
Testprogramme\TestProject 0\Test 0\Debug\Test 0.exe : fatal error LNK1120: 1 
unresolvedexternals

Build log was saved at"file://h:\C\Dokumente und 
Einstellungen\Clemens\EigeneDateien\Diverse\Clemens\Universitaet\C++\Visual C++ 
Testprogramme\TestProject 0\Test 0\Debug\BuildLog.htm"
Test 0 - 2 error(s), 0 warning(s)


---------------------- Done ----------------------

    Build: 0 succeeded, 1 failed, 0 skipped

Following the suggestions made on
 
        http://sources.redhat.com/ml/gsl-discuss/2004-q2/msg00000.html

I have added 




        "libgslcblas.a libgsl.a"
under 




        Configuration Properties->Linker->Input->AdditionalDependencies
Could it have anything to do with these additionally setproperties? Or do you 
have any other idea what the problem might be andwhat I could change in order 
to make the program work?

Thank you very much already in advance!

Clemens
.
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