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Diffstat (limited to 'src/2geom/conjugate_gradient.cpp')
| -rw-r--r-- | src/2geom/conjugate_gradient.cpp | 143 |
1 files changed, 0 insertions, 143 deletions
diff --git a/src/2geom/conjugate_gradient.cpp b/src/2geom/conjugate_gradient.cpp deleted file mode 100644 index 588513414..000000000 --- a/src/2geom/conjugate_gradient.cpp +++ /dev/null @@ -1,143 +0,0 @@ -/* - * conjugate_gradient.cpp - * - * Copyright 2006 Nathan Hurst <njh@mail.csse.monash.edu.au> - * - * This library is free software; you can redistribute it and/or - * modify it either under the terms of the GNU Lesser General Public - * License version 2.1 as published by the Free Software Foundation - * (the "LGPL") or, at your option, under the terms of the Mozilla - * Public License Version 1.1 (the "MPL"). If you do not alter this - * notice, a recipient may use your version of this file under either - * the MPL or the LGPL. - * - * You should have received a copy of the LGPL along with this library - * in the file COPYING-LGPL-2.1; if not, write to the Free Software - * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA - * You should have received a copy of the MPL along with this library - * in the file COPYING-MPL-1.1 - * - * The contents of this file are subject to the Mozilla Public License - * Version 1.1 (the "License"); you may not use this file except in - * compliance with the License. You may obtain a copy of the License at - * http://www.mozilla.org/MPL/ - * - * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY - * OF ANY KIND, either express or implied. See the LGPL or the MPL for - * the specific language governing rights and limitations. - * - */ - -#include <math.h> -#include <stdlib.h> -#include <valarray> -#include <cassert> -#include <2geom/conjugate_gradient.h> - -/* lifted wholely from wikipedia. */ - -namespace Geom -{ - -using std::valarray; - -static void -matrix_times_vector(valarray<double> const &matrix, /* m * n */ - valarray<double> const &vec, /* n */ - valarray<double> &result) /* m */ -{ - unsigned n = vec.size(); - unsigned m = result.size(); - assert(m*n == matrix.size()); - const double* mp = &const_cast<valarray<double>&>(matrix)[0]; - for (unsigned i = 0; i < m; i++) { - double res = 0; - for (unsigned j = 0; j < n; j++) - res += *mp++ * vec[j]; - result[i] = res; - } -} - -/** -// only used in commented code below -static double Linfty(valarray<double> const &vec) { - return std::max(vec.max(), -vec.min()); -} -**/ - -double -inner(valarray<double> const &x, - valarray<double> const &y) { - double total = 0; - for(unsigned i = 0; i < x.size(); i++) - total += x[i]*y[i]; - return total;// (x*y).sum(); <- this is more concise, but ineff -} - -void -conjugate_gradient(double **A, - double *x, - double *b, - unsigned n, - double tol, - int max_iterations, - bool ortho1) { - valarray<double> vA(n*n); - valarray<double> vx(n); - valarray<double> vb(n); - for(unsigned i=0;i<n;i++) { - vx[i]=x[i]; - vb[i]=b[i]; - for(unsigned j=0;j<n;j++) { - vA[i*n+j]=A[i][j]; - } - } - conjugate_gradient(vA,vx,vb,n,tol,max_iterations,ortho1); - for(unsigned i=0;i<n;i++) { - x[i]=vx[i]; - } -} -void -conjugate_gradient(valarray<double> const &A, - valarray<double> &x, - valarray<double> const &b, - unsigned n, double tol, - unsigned max_iterations, bool /*ortho1*/) { - valarray<double> Ap(n), p(n), r(n); - matrix_times_vector(A,x,Ap); - r=b-Ap; - double r_r = inner(r,r); - unsigned k = 0; - tol *= tol; - while(k < max_iterations && r_r > tol) { - k++; - double r_r_new = r_r; - if(k == 1) - p = r; - else { - r_r_new = inner(r,r); - p = r + (r_r_new/r_r)*p; - } - matrix_times_vector(A, p, Ap); - double alpha_k = r_r_new / inner(p, Ap); - x += alpha_k*p; - r -= alpha_k*Ap; - r_r = r_r_new; - } - //printf("njh: %d iters, Linfty = %g L2 = %g\n", k, - //std::max(-r.min(), r.max()), sqrt(r_r)); - // x is solution -} - -} // namespace Geom - -/* - Local Variables: - mode:c++ - c-file-style:"stroustrup" - c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) - indent-tabs-mode:nil - fill-column:99 - End: -*/ -// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 : |