Текст программы

#include <iostream>

#define nmax 100

using namespace std;

class diffur

{

public:

int n;

float z[100], zn[100];

float zp[100];

float A[100][100];

float z0[100], f0[100];

float h;

float tfinal;

void f (float t,float y[100],float yp[100])

{

yp[1]= A[1][1]*y[1] + A[1][2]*y[2] + A[1][3]*y[3] + f0[1];

yp[2]= A[2][1]*y[1] + A[2][2]*y[2] + A[2][3]*y[3] + f0[2];

yp[3]= A[3][1]*y[1] + A[3][2]*y[2] + A[3][3]*y[3] + f0[3];

}

void SetBeginData()

{

n = 3;

A[1][1] = -6; A[1][2] = -2; A[1][3] = -12; f0[1] = 16; z0[1] = 2;

A[2][1] = -16; A[2][2] = -17; A[2][3] = 17; f0[2] = -18; z0[2] = 0;

A[3][1] = 44; A[3][2] = 3; A[3][3] = -45; f0[3] = 4; z0[3] = -2;

h = 2 / NormMatrix(3, A);

tfinal = 4.0;

}

float NormMatrix(int n,float A[100][100])

{

int i, j;

float Sum, FullSum;

FullSum = 0;

for (i=1;i<=n;i++)

{

Sum = 0;

for (j=1;j<=n;j++)

{

Sum = Sum + (A[i][j])*(A[i][j]);

}

FullSum = FullSum + Sum;

}

return sqrt(FullSum);

}

void IntegrateMethod()

{

int i, j;

float t, tout;

FILE *f1,*f2,*f3,*f4;

f1=fopen("t.txt","w");

f2=fopen("y1.txt","w");

f3=fopen("y2.txt","w");

f4=fopen("y3.txt","w");

t = 0;

tout = 1.0;

for (i=1;i<=n;i++)

z[i] = z0[i];

while (t < tout + h)

{

fprintf(f1,"%f\n",t);

fprintf(f2,"%f\n",z[1]);

fprintf(f3,"%f\n",z[2]);

fprintf(f4,"%f\n",z[3]);

f(t, z, zp);

for (i=1;i<=n;i++)

zn[i] = z[i] + h/4 * zp[i];

f(t+h/4, zn, zp);

for (i=1;i<=n;i++)

z[i] = z[i] + h * (-zp[i]+2*zp[i]);

t = t + h;

}

fclose(f1);

fclose(f2);

fclose(f3);

fclose(f4);

}

};

void main()

{

diffur a;

a.SetBeginData();

a.IntegrateMethod();

}

Таблица полученная своим методом

Таблица полученная методом RKF45

Поиск по сайту: