77 lines
2.1 KiB
C
77 lines
2.1 KiB
C
/*
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* Copyright (C) NHR@FAU, University Erlangen-Nuremberg.
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* All rights reserved. This file is part of nusif-solver.
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* Use of this source code is governed by a MIT style
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* license that can be found in the LICENSE file.
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*/
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#include "solver.h"
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#include "util.h"
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void initSolver(Solver* s, Discretization* d, Parameter* p)
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{
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s->grid = &d->grid;
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s->itermax = p->itermax;
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s->eps = p->eps;
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s->omega = p->omg;
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}
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void solve(Solver* solver, double* p, double* rhs)
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{
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int imax = solver->grid->imax;
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int jmax = solver->grid->jmax;
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double eps = solver->eps;
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int itermax = solver->itermax;
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double dx2 = solver->grid->dx * solver->grid->dx;
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double dy2 = solver->grid->dy * solver->grid->dy;
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double idx2 = 1.0 / dx2;
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double idy2 = 1.0 / dy2;
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double factor = solver->omega * 0.5 * (dx2 * dy2) / (dx2 + dy2);
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double epssq = eps * eps;
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int it = 0;
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double res = 1.0;
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int pass, jsw, isw;
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while ((res >= epssq) && (it < itermax)) {
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res = 0.0;
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jsw = 1;
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for (pass = 0; pass < 2; pass++) {
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isw = jsw;
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for (int j = 1; j < jmax + 1; j++) {
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for (int i = isw; i < imax + 1; i += 2) {
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double r = RHS(i, j) -
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((P(i + 1, j) - 2.0 * P(i, j) + P(i - 1, j)) * idx2 +
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(P(i, j + 1) - 2.0 * P(i, j) + P(i, j - 1)) * idy2);
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P(i, j) -= (factor * r);
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res += (r * r);
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}
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isw = 3 - isw;
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}
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jsw = 3 - jsw;
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}
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for (int i = 1; i < imax + 1; i++) {
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P(i, 0) = P(i, 1);
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P(i, jmax + 1) = P(i, jmax);
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}
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for (int j = 1; j < jmax + 1; j++) {
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P(0, j) = P(1, j);
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P(imax + 1, j) = P(imax, j);
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}
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res = res / (double)(imax * jmax);
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#ifdef DEBUG
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printf("%d Residuum: %e\n", it, res);
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#endif
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it++;
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}
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#ifdef VERBOSE
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printf("Solver took %d iterations to reach %f\n", it, sqrt(res));
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#endif
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}
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