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#include <stdlib.h>
#include <stdio.h>
#include <sys/time.h>
#include <gsl/gsl_vector.h>
#include <gsl/gsl_matrix.h>
#include <gsl/gsl_blas.h>
#include <gsl/gsl_multilarge_nlinear.h>
#include <gsl/gsl_spblas.h>
#include <gsl/gsl_spmatrix.h>
/* parameters for functions */
struct model_params
{
double alpha;
gsl_spmatrix *J;
};
/* penalty function */
int
penalty_f (const gsl_vector * x, void *params, gsl_vector * f)
{
struct model_params *par = (struct model_params *) params;
const double sqrt_alpha = sqrt(par->alpha);
const size_t p = x->size;
size_t i;
double sum = 0.0;
for (i = 0; i < p; ++i)
{
double xi = gsl_vector_get(x, i);
gsl_vector_set(f, i, sqrt_alpha*(xi - 1.0));
sum += xi * xi;
}
gsl_vector_set(f, p, sum - 0.25);
return GSL_SUCCESS;
}
int
penalty_df (CBLAS_TRANSPOSE_t TransJ, const gsl_vector * x,
const gsl_vector * u, void * params, gsl_vector * v,
gsl_matrix * JTJ)
{
struct model_params *par = (struct model_params *) params;
const size_t p = x->size;
size_t j;
/* store 2*x in last row of J */
for (j = 0; j < p; ++j)
{
double xj = gsl_vector_get(x, j);
gsl_spmatrix_set(par->J, p, j, 2.0 * xj);
}
/* compute v = op(J) u */
if (v)
gsl_spblas_dgemv(TransJ, 1.0, par->J, u, 0.0, v);
if (JTJ)
{
gsl_vector_view diag = gsl_matrix_diagonal(JTJ);
/* compute J^T J = [ alpha*I_p + 4 x x^T ] */
gsl_matrix_set_zero(JTJ);
/* store 4 x x^T in lower half of JTJ */
gsl_blas_dsyr(CblasLower, 4.0, x, JTJ);
/* add alpha to diag(JTJ) */
gsl_vector_add_constant(&diag.vector, par->alpha);
}
return GSL_SUCCESS;
}
int
penalty_fvv (const gsl_vector * x, const gsl_vector * v,
void *params, gsl_vector * fvv)
{
const size_t p = x->size;
double normv = gsl_blas_dnrm2(v);
gsl_vector_set_zero(fvv);
gsl_vector_set(fvv, p, 2.0 * normv * normv);
(void)params; /* avoid unused parameter warning */
return GSL_SUCCESS;
}
void
solve_system(const gsl_vector *x0, gsl_multilarge_nlinear_fdf *fdf,
gsl_multilarge_nlinear_parameters *params)
{
const gsl_multilarge_nlinear_type *T = gsl_multilarge_nlinear_trust;
const size_t max_iter = 200;
const double xtol = 1.0e-8;
const double gtol = 1.0e-8;
const double ftol = 1.0e-8;
const size_t n = fdf->n;
const size_t p = fdf->p;
gsl_multilarge_nlinear_workspace *work =
gsl_multilarge_nlinear_alloc(T, params, n, p);
gsl_vector * f = gsl_multilarge_nlinear_residual(work);
gsl_vector * x = gsl_multilarge_nlinear_position(work);
int info;
double chisq0, chisq, rcond, xsq;
struct timeval tv0, tv1;
gettimeofday(&tv0, NULL);
/* initialize solver */
gsl_multilarge_nlinear_init(x0, fdf, work);
/* store initial cost */
gsl_blas_ddot(f, f, &chisq0);
/* iterate until convergence */
gsl_multilarge_nlinear_driver(max_iter, xtol, gtol, ftol,
NULL, NULL, &info, work);
gettimeofday(&tv1, NULL);
/* store final cost */
gsl_blas_ddot(f, f, &chisq);
/* compute final ||x||^2 */
gsl_blas_ddot(x, x, &xsq);
/* store cond(J(x)) */
gsl_multilarge_nlinear_rcond(&rcond, work);
/* print summary */
fprintf(stderr, "%-25s %-5zu %-4zu %-5zu %-6zu %-4zu %-10.4e %-10.4e %-7.2f %-11.4e %.2f\n",
gsl_multilarge_nlinear_trs_name(work),
gsl_multilarge_nlinear_niter(work),
fdf->nevalf,
fdf->nevaldfu,
fdf->nevaldf2,
fdf->nevalfvv,
chisq0,
chisq,
1.0 / rcond,
xsq,
(tv1.tv_sec - tv0.tv_sec) + 1.0e-6 * (tv1.tv_usec - tv0.tv_usec));
gsl_multilarge_nlinear_free(work);
}
int
main (void)
{
const size_t p = 2000;
const size_t n = p + 1;
gsl_vector *f = gsl_vector_alloc(n);
gsl_vector *x = gsl_vector_alloc(p);
/* allocate sparse Jacobian matrix with 2*p non-zero elements in triplet format */
gsl_spmatrix *J = gsl_spmatrix_alloc_nzmax(n, p, 2 * p, GSL_SPMATRIX_TRIPLET);
gsl_multilarge_nlinear_fdf fdf;
gsl_multilarge_nlinear_parameters fdf_params =
gsl_multilarge_nlinear_default_parameters();
struct model_params params;
size_t i;
params.alpha = 1.0e-5;
params.J = J;
/* define function to be minimized */
fdf.f = penalty_f;
fdf.df = penalty_df;
fdf.fvv = penalty_fvv;
fdf.n = n;
fdf.p = p;
fdf.params = ¶ms;
for (i = 0; i < p; ++i)
{
/* starting point */
gsl_vector_set(x, i, i + 1.0);
/* store sqrt(alpha)*I_p in upper p-by-p block of J */
gsl_spmatrix_set(J, i, i, sqrt(params.alpha));
}
fprintf(stderr, "%-25s %-4s %-4s %-5s %-6s %-4s %-10s %-10s %-7s %-11s %-10s\n",
"Method", "NITER", "NFEV", "NJUEV", "NJTJEV", "NAEV", "Init Cost",
"Final cost", "cond(J)", "Final |x|^2", "Time (s)");
fdf_params.scale = gsl_multilarge_nlinear_scale_levenberg;
fdf_params.trs = gsl_multilarge_nlinear_trs_lm;
solve_system(x, &fdf, &fdf_params);
fdf_params.trs = gsl_multilarge_nlinear_trs_lmaccel;
solve_system(x, &fdf, &fdf_params);
fdf_params.trs = gsl_multilarge_nlinear_trs_dogleg;
solve_system(x, &fdf, &fdf_params);
fdf_params.trs = gsl_multilarge_nlinear_trs_ddogleg;
solve_system(x, &fdf, &fdf_params);
fdf_params.trs = gsl_multilarge_nlinear_trs_subspace2D;
solve_system(x, &fdf, &fdf_params);
fdf_params.trs = gsl_multilarge_nlinear_trs_cgst;
solve_system(x, &fdf, &fdf_params);
gsl_vector_free(f);
gsl_vector_free(x);
gsl_spmatrix_free(J);
return 0;
}
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