#define meyer_N 16
#define meyer_P 3
#define meyer_NTRIES 1
static double meyer_x0[meyer_P] = { 0.02, 4000.0, 250.0 };
static double meyer_epsrel = 1.0e-8;
static double meyer_Y[meyer_N] = {
34780., 28610., 23650., 19630., 16370., 13720., 11540.,
9744., 8261., 7030., 6005., 5147., 4427., 3820.,
3307., 2872.
};
static void
meyer_checksol(const double x[], const double sumsq,
const double epsrel, const char *sname,
const char *pname)
{
size_t i;
const double sumsq_exact = 8.794585517053883e+01;
const double meyer_x[meyer_P] = { 5.609636471049458e-03,
6.181346346283188e+03,
3.452236346240292e+02 };
gsl_test_rel(sumsq, sumsq_exact, epsrel, "%s/%s sumsq",
sname, pname);
for (i = 0; i < meyer_P; ++i)
{
gsl_test_rel(x[i], meyer_x[i], epsrel, "%s/%s i=%zu",
sname, pname, i);
}
}
static int
meyer_f (const gsl_vector * x, void *params, gsl_vector * f)
{
double x1 = gsl_vector_get(x, 0);
double x2 = gsl_vector_get(x, 1);
double x3 = gsl_vector_get(x, 2);
size_t i;
for (i = 0; i < meyer_N; ++i)
{
double ti = 45.0 + 5.0*(i + 1.0);
double yi = meyer_Y[i];
double fi = x1 * exp(x2 / (ti + x3)) - yi;
gsl_vector_set(f, i, fi);
}
return GSL_SUCCESS;
}
static int
meyer_df (const gsl_vector * x, void *params, gsl_matrix * J)
{
double x1 = gsl_vector_get(x, 0);
double x2 = gsl_vector_get(x, 1);
double x3 = gsl_vector_get(x, 2);
size_t i;
for (i = 0; i < meyer_N; ++i)
{
double ti = 45.0 + 5.0*(i + 1.0);
double term1 = ti + x3;
double term2 = exp(x2 / term1);
gsl_matrix_set(J, i, 0, term2);
gsl_matrix_set(J, i, 1, x1*term2/term1);
gsl_matrix_set(J, i, 2, -x1*x2*term2/(term1*term1));
}
return GSL_SUCCESS;
}
static gsl_multifit_function_fdf meyer_func =
{
&meyer_f,
&meyer_df,
NULL,
meyer_N,
meyer_P,
NULL,
0,
0
};
static test_fdf_problem meyer_problem =
{
"meyer",
meyer_x0,
NULL,
&meyer_epsrel,
meyer_NTRIES,
&meyer_checksol,
&meyer_func
};