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#include <math.h>
#include <stdio.h>
#include <string.h>
#include <math.h>
#include <arrayfire.h>
#include "../common/progress.h"
using namespace af;
Window *win;
array normalize(array a, float max)
{
float mx = max * 0.5;
float mn = -max * 0.5;
return (a-mn)/(mx-mn);
}
static void swe(bool console)
{
double time_total = 20; // run for N seconds
// Grid length, number and spacing
const unsigned Lx = 512, nx = Lx + 1;
const unsigned Ly = 512, ny = Ly + 1;
const float dx = Lx / (nx - 1);
const float dy = Ly / (ny - 1);
array ZERO = constant(0, nx, ny);
array um = ZERO, vm = ZERO;
unsigned io = (unsigned)floor(Lx / 5.0f),
jo = (unsigned)floor(Ly / 5.0f),
k = 20;
array x = tile(moddims(seq(nx),nx,1), 1,ny);
array y = tile(moddims(seq(ny),1,ny), nx,1);
// Initial condition
array etam = 0.01f * exp((-((x - io) * (x - io) + (y - jo) * (y - jo))) / (k * k));
float m_eta = max<float>(etam);
array eta = etam;
float dt = 0.5;
// conv kernels
float h_diff_kernel[] = {9.81f * (dt / dx), 0, -9.81f * (dt / dx)};
float h_lap_kernel[] = {0, 1, 0, 1, -4, 1, 0, 1, 0};
array h_diff_kernel_arr(3, h_diff_kernel);
array h_lap_kernel_arr(3, 3, h_lap_kernel);
if(!console) {
win = new Window(512, 512,"Shallow Water Equations");
win->setColorMap(AF_COLORMAP_MOOD);
}
timer t = timer::start();
unsigned iter = 0;
while (progress(iter, t, time_total)) {
// compute
array up = um + convolve(eta, h_diff_kernel_arr);
array vp = um + convolve(eta, h_diff_kernel_arr.T());
array e = convolve(eta, h_lap_kernel_arr);
array etap = 2 * eta - etam + (2 * dt * dt) / (dx * dy) * e;
etam = eta;
eta = etap;
if (!console) {
win->image(normalize(eta, m_eta));
// viz
} else eval(eta, up, vp);
iter++;
}
}
int main(int argc, char* argv[])
{
int device = argc > 1 ? atoi(argv[1]) : 0;
bool console = argc > 2 ? argv[2][0] == '-' : false;
try {
af::setDevice(device);
af::info();
printf("Simulation of shallow water equations\n");
swe(console);
} catch (af::exception& e) {
fprintf(stderr, "%s\n", e.what());
throw;
}
return 0;
}
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