static double
my_f (const gsl_vector *v, void *params)
{
double val;
my_fdf(v, params, &val, NULL);
return val;
}
void measurement_df(const gsl_vector *v, void *params, gsl_vector *df) {
double f;
my_fdf(v, params, &f, df);
}
/* The gradient of f, df = (df/dx, df/dy). */
static void
my_df (const gsl_vector *v, void *params, gsl_vector *df)
{
my_fdf(v, params, NULL, df);
}
void minim(density_t * ndft){
const gsl_multimin_fdfminimizer_type *T;
gsl_multimin_fdfminimizer *s;
gsl_multimin_function_fdf my_func;
gsl_vector * grad_initial;
size_t iter;
ipf_t ipf_previous;
int status;
double minimum, g_initial, norm_initial;
char * output_string;
int i;
params_gsl_multimin_function_t params;
output_string = (char *) malloc(25*sizeof(char));
params.nDFT = density_get_val(ndft);
my_func.n = ipf.npar;
my_func.f = my_f;
my_func.df = my_df;
my_func.fdf = my_fdf;
my_func.params = (void *) (¶ms);
/* We use the BFGS algorithm from thee GNU Scientific Library (GSL)
in its optimized version bfgs2 */
T = gsl_multimin_fdfminimizer_vector_bfgs2;
messages_basic("\n\nStarting the optimization.\n\n\n");
grad_initial = gsl_vector_alloc(ipf.npar);
my_fdf (ipf.gamma, ¶ms, &g_initial, grad_initial);
norm_initial = gsl_blas_dnrm2(grad_initial);
if(g_initial < epsilon_gvalue){
if(myid == 0) printf("The value of G for the starting gamma is %.12lg,\n", g_initial);
if(myid == 0) printf("which is already below the requested threshold of %.12lg\n", epsilon_gvalue);
parallel_end(EXIT_SUCCESS);
}
if(norm_initial < epsilon_grad){
if(myid == 0) printf("The value of the normm of the gradient of G for the starting gamma is %.12lg,\n", norm_initial);
if(myid == 0) printf("which is already below the requested threshold of %.12lg\n", epsilon_grad);
parallel_end(EXIT_SUCCESS);
}
if(myid == 0) printf(" Starting from gamma = ");
if(myid == 0) {for(i = 0; i < ipf.npar; i++) printf ("%.5f ", gsl_vector_get (ipf.gamma, i));}
if(myid == 0) printf("\n G(gamma) = %.12lg\n", g_initial);
if(myid == 0) printf(" ||Grad G(gamma)|| = %.12lg\n\n", norm_initial);
/* Initialization of the minimizer s for the function
my_func starting at the x point
The step for the first try is 0.1
and the convergence criteria is 0.1 */
messages_basic("\n\nInitialization of the minimizer.\n\n\n");
s = gsl_multimin_fdfminimizer_alloc (T, ipf.npar);
gsl_multimin_fdfminimizer_set (s, &my_func, ipf.gamma, 0.1, 0.1);
minimum = g_initial;
iter = 0;
do{
iter++;
ipf_copy(&ipf_previous, &ipf);
if(myid == 0) printf(" Iter = %d\n", (int)iter);
if(myid == 0) printf(" starting gamma = ");
if(myid == 0) {for(i = 0; i < ipf.npar; i++) printf ("%.5f ", gsl_vector_get (gsl_multimin_fdfminimizer_x(s), i));}
if(myid == 0) printf("\n starting G(gamma) = %15.10f\n", minimum);
/* We make an iteration of the minimizer s */
status = gsl_multimin_fdfminimizer_iterate (s);
minimum = gsl_multimin_fdfminimizer_minimum(s);
if (status){
if(myid == 0) printf(" Breaking. Reason: %s\n", gsl_strerror(status));
break;
}
if(myid == 0) printf(" ||Grad G(gamma)|| = %15.10f\n", gsl_blas_dnrm2(gsl_multimin_fdfminimizer_gradient(s)));
if(myid == 0) printf(" G(gamma) = %15.10f\n", minimum);
/* Checks convergence */
if(minimum < epsilon_gvalue){
status = GSL_SUCCESS;
}else{
status = gsl_multimin_test_gradient (gsl_multimin_fdfminimizer_gradient(s), epsilon_grad);
}
gsl_vector_memcpy(ipf.gamma, gsl_multimin_fdfminimizer_x(s));
ipf_write(ipf, ipf_ref, "intermediate-pot");
/* Print the diff between initial and reference IPFs */
if(myid == 0) printf(" Diff[ IPF(previous), IPF(new) ] = %.12lg\n", ipf_diff(&ipf_previous, &ipf));
ipf_end(&ipf_previous);
}
while (status == GSL_CONTINUE && iter < minim_maxiter);
if(myid == 0) printf("\n\nFinished optimization. status = %d (%s)\n", status, gsl_strerror(status));
if(myid == 0) printf(" Final gamma = ");
if(myid == 0) {for(i = 0; i < ipf.npar; i++) printf ("%.5f ", gsl_vector_get (gsl_multimin_fdfminimizer_x(s), i));}
if(myid == 0) printf("\n With value: G(gamma) = %.12lg\n\n", gsl_multimin_fdfminimizer_minimum(s));
gsl_vector_memcpy(ipf.gamma, gsl_multimin_fdfminimizer_x(s));
sprintf(output_string, "pot");
ipf_write(ipf, ipf_ref, output_string);
gsl_multimin_fdfminimizer_free (s);
fflush(stdout);
}
