jacobn.c

Numerical Recipes in C的源代码

void jacobn(float x, float y[], float dfdx[], float **dfdy, int n)
{
	int i;

	for (i=1;i<=n;i++) dfdx[i]=0.0;
	dfdy[1][1] = -0.013-1000.0*y[3];
	dfdy[1][2]=0.0;
	dfdy[1][3] = -1000.0*y[1];
	dfdy[2][1]=0.0;
	dfdy[2][2] = -2500.0*y[3];
	dfdy[2][3] = -2500.0*y[2];
	dfdy[3][1] = -0.013-1000.0*y[3];
	dfdy[3][2] = -2500.0*y[3];
	dfdy[3][3] = -1000.0*y[1]-2500.0*y[2];
}

void derivs(float x, float y[], float dydx[])
{
	dydx[1] = -0.013*y[1]-1000.0*y[1]*y[3];
	dydx[2] = -2500.0*y[2]*y[3];
	dydx[3] = -0.013*y[1]-1000.0*y[1]*y[3]-2500.0*y[2]*y[3];
}