Resistor mesh: Difference between revisions
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Line 187:
return 0;
}</lang>
=={{header|C++}}==
{{trans|C#}}
<lang cpp>#include <iomanip>
#include <iostream>
#include <vector>
class Node {
private:
double v;
int fixed;
public:
Node() : v(0.0), fixed(0) {
// empty
}
Node(double v, int fixed) : v(v), fixed(fixed) {
// empty
}
double getV() const {
return v;
}
void setV(double nv) {
v = nv;
}
int getFixed() const {
return fixed;
}
void setFixed(int nf) {
fixed = nf;
}
};
void setBoundary(std::vector<std::vector<Node>>& m) {
m[1][1].setV(1.0);
m[1][1].setFixed(1);
m[6][7].setV(-1.0);
m[6][7].setFixed(-1);
}
double calculateDifference(const std::vector<std::vector<Node>>& m, std::vector<std::vector<Node>>& d, const int w, const int h) {
double total = 0.0;
for (int i = 0; i < h; ++i) {
for (int j = 0; j < w; ++j) {
double v = 0.0;
int n = 0;
if (i > 0) {
v += m[i - 1][j].getV();
n++;
}
if (j > 0) {
v += m[i][j - 1].getV();
n++;
}
if (i + 1 < h) {
v += m[i + 1][j].getV();
n++;
}
if (j + 1 < w) {
v += m[i][j + 1].getV();
n++;
}
v = m[i][j].getV() - v / n;
d[i][j].setV(v);
if (m[i][j].getFixed() == 0) {
total += v * v;
}
}
}
return total;
}
double iter(std::vector<std::vector<Node>>& m, const int w, const int h) {
using namespace std;
vector<vector<Node>> d;
for (int i = 0; i < h; ++i) {
vector<Node> t(w);
d.push_back(t);
}
double curr[] = { 0.0, 0.0, 0.0 };
double diff = 1e10;
while (diff > 1e-24) {
setBoundary(m);
diff = calculateDifference(m, d, w, h);
for (int i = 0; i < h; ++i) {
for (int j = 0; j < w; ++j) {
m[i][j].setV(m[i][j].getV() - d[i][j].getV());
}
}
}
for (int i = 0; i < h; ++i) {
for (int j = 0; j < w; ++j) {
int k = 0;
if (i != 0) ++k;
if (j != 0) ++k;
if (i < h - 1) ++k;
if (j < w - 1) ++k;
curr[m[i][j].getFixed() + 1] += d[i][j].getV()*k;
}
}
return (curr[2] - curr[0]) / 2.0;
}
const int S = 10;
int main() {
using namespace std;
vector<vector<Node>> mesh;
for (int i = 0; i < S; ++i) {
vector<Node> t(S);
mesh.push_back(t);
}
double r = 2.0 / iter(mesh, S, S);
cout << "R = " << setprecision(15) << r << '\n';
return 0;
}</lang>
{{out}}
<pre>R = 1.60899124172989</pre>
=={{header|C#|C sharp}}==
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