void write_slice(const char *filename, const Grid3DDevice<double> &grid)
{
Grid3DHost<double> h_grid;
h_grid.init_congruent(grid);
h_grid.copy_all_data(grid);
int nx = grid.nx();
int ny = grid.ny();
int nz = grid.nz();
ImageFile img;
img.allocate(nx, ny);
for (int i=0; i < nx; i++)
for (int j=0; j < ny; j++) {
double temperature = h_grid.at(i,j,nz/2);
if (temperature < -2) temperature = -2;
if (temperature > 2) temperature = 2;
//float3 color = make_float3(temperature, temperature, temperature);
float3 color = hsv_to_rgb(make_float3((temperature)*360, 1, 1));
//float3 color = pseudo_temperature((temperature+1)*.5);
img.set_rgb(i,j,(unsigned char)(255*color.x),(unsigned char)(255*color.y),(unsigned char)(255*color.z));
}
img.write_ppm(filename);
}
int main(int argc, char **argv)
{
Eqn_Diffusion1DParams params;
params.h = 1;
params.nx = 100;
params.left.type = BC_NEUMANN;
params.left.value = 0;
params.right.type = BC_NEUMANN;
params.right.value = 0;
params.diffusion_coefficient = 1;
params.initial_values.init(100, 0);
int i,t;
// initialize to an impulse
for (i=0; i < 100; i++) {
if (i < 40) params.initial_values.at(i) = 0;
else if (i < 60) params.initial_values.at(i) = 1;
else params.initial_values.at(i) = 0;
}
Eqn_Diffusion1D eqn;
if (!eqn.set_parameters(params))
assert(false);
ImageFile img;
img.allocate(100, 800);
for (t=0; t < 800; t++) {
eqn.advance(.1);
eqn.copy_density_to_host();
for (int i=0; i < 100; i++) {
float soln_val = eqn.density().at(i);
if (soln_val > 1.0f) soln_val = 1.0f;
unsigned char color = (unsigned char) (255 * (soln_val / 1.0f));
img.set_rgb(i,t, color, color, color);
}
}
img.write_ppm("solution.ppm");
global_timer_print();
return 0;
}