int main()
{
void *cpode_mem;
N_Vector yref, yy0;
realtype tol, tout;
int i, flag;
tout = 30.0;
/* Get reference solution */
yref = N_VNew_Serial(4);
RefSol(tout, yref);
/* Initialize solver */
tol = TOL;
cpode_mem = CPodeCreate(CP_EXPL, CP_BDF, CP_NEWTON);
yy0 = N_VNew_Serial(4);
Ith(yy0,1) = 1.0; /* x */
Ith(yy0,2) = 0.0; /* y */
Ith(yy0,3) = 0.0; /* xd */
Ith(yy0,4) = 0.0; /* yd */
flag = CPodeInit(cpode_mem, (void *)f, NULL, 0.0, yy0, NULL, CP_SS, tol, &tol);
flag = CPodeSetMaxNumSteps(cpode_mem, 50000);
flag = CPodeSetStopTime(cpode_mem, tout);
flag = CPodeProjDefine(cpode_mem, proj, NULL);
flag = CPDense(cpode_mem, 4);
for (i=0;i<5;i++) {
printf("\n\n%.2e\n", tol);
GetSol(cpode_mem, yy0, tol, tout, TRUE, yref);
GetSol(cpode_mem, yy0, tol, tout, FALSE, yref);
tol /= 10.0;
}
N_VDestroy_Serial(yref);
CPodeFree(&cpode_mem);
return(0);
}
//
// Writes the solution the the file $path$.
// The solution is written for $pointNo$ points.
//
void OdeProb::WriteSol(const char* path, size_t pointNo) const
{
const double dx = (XBack() - XFront()) / (pointNo -1);
double x;
FILE* out;
out = fopen(path, "wt");
assert(out);
x = XFront();
for(size_t i = 0; i < pointNo - 1; i++)
{
fprintf(out, "%20lf\t%20lf\n", x, GetSol(x));
x += dx;
}
// The last point must be written (to avoid the rounding errors)
x = XBack();
fprintf(out, "%20lf\t%20lf\n", x, GetSol(x));
fclose(out);
}
