#define box_N 10 /* can be >= p */
#define box_P 3
#define box_NTRIES 1
static double box_x0[box_P] = { 0.0, 10.0, 20.0 };
static double box_epsrel = 1.0e-12;
static void
box_checksol(const double x[], const double sumsq,
const double epsrel, const char *sname,
const char *pname)
{
size_t i;
const double sumsq_exact = 0.0;
const double box_x[box_P] = { 1.0, 10.0, 1.0 };
gsl_test_rel(sumsq, sumsq_exact, epsrel, "%s/%s sumsq",
sname, pname);
for (i = 0; i < box_P; ++i)
{
gsl_test_rel(x[i], box_x[i], epsrel, "%s/%s i=%zu",
sname, pname, i);
}
}
static int
box_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 < box_N; ++i)
{
double ti = (i + 1.0) / 10.0;
double fi = exp(-x1*ti) - exp(-x2*ti) - x3*(exp(-ti) - exp(-10.0*ti));
gsl_vector_set(f, i, fi);
}
return GSL_SUCCESS;
}
static int
box_df (const gsl_vector * x, void *params, gsl_matrix * J)
{
double x1 = gsl_vector_get(x, 0);
double x2 = gsl_vector_get(x, 1);
size_t i;
for (i = 0; i < box_N; ++i)
{
double ti = (i + 1.0) / 10.0;
double term1 = exp(-x1*ti);
double term2 = exp(-x2*ti);
double term3 = exp(-10.0*ti) - exp(-ti);
gsl_matrix_set(J, i, 0, -ti*term1);
gsl_matrix_set(J, i, 1, ti*term2);
gsl_matrix_set(J, i, 2, term3);
}
return GSL_SUCCESS;
}
static gsl_multifit_function_fdf box_func =
{
&box_f,
&box_df,
NULL,
box_N,
box_P,
NULL,
0,
0
};
static test_fdf_problem box_problem =
{
"box3d",
box_x0,
NULL,
&box_epsrel,
box_NTRIES,
&box_checksol,
&box_func
};