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Commit 86ad36da authored by Matthieu Schaller's avatar Matthieu Schaller
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Redefined all the kernel functions in a unique and physically motivated way

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1 merge request!138More physical definition of SPH kernel functions
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src/kernel_hydro.h
+ 84
− 15
View file @ 86ad36da
......@@ -26,8 +26,7 @@
#include "inline.h"
#include "vector.h"
/* ----------------------------------------------------------------------------- */
/* ------------------------------------------------------------------------- */
#if defined(CUBIC_SPLINE_KERNEL)
/* Coefficients for the kernel. */
......@@ -36,13 +35,50 @@
#define kernel_ivals 2
#define kernel_gamma 1.825742
#define kernel_constant 16. * M_1_PI
static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
__attribute__((aligned(16))) = {3.f, -3.f, 0.f, 0.5f, /* 0 < u < 0.5 */
-1.f, 3.f, -3.f, 1.f, /* 0.5 < u < 1 */
0.f, 0.f, 0.f, 0.f}; /* 1 < u */
/* ------------------------------------------------------------------------- */
#elif defined(QUARTIC_SPLINE_KERNEL)
/* Coefficients for the kernel. */
#define kernel_name "Quartic spline (M5)"
#define kernel_degree 4
#define kernel_ivals 5
#define kernel_gamma 2.018932
#define kernel_constant 15625. * M_1_PI / 512.
static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
__attribute__((aligned(16))) = {
+48.f * M_1_PI, -48.f * M_1_PI, 0.f, +8.f * M_1_PI,
-16.f * M_1_PI, +48.f * M_1_PI, -48.f * M_1_PI, +16.f * M_1_PI,
0.f, 0.f, 0.f, 0.f};
6.f, 0.f, -2.4f, 0.f, 0.368f, /* 0 < u < 0.2 */
-4.f, 8.f, -4.8f, 0.32f, 0.352f, /* 0.2 < u < 0.4 */
-4.f, 8.f, -4.8f, 0.32f, 0.352f, /* 0.4 < u < 0.6 */
1.f, -4.f, 6.f, -4.f, 1.f, /* 0.6 < u < 0.8 */
1.f, -4.f, 6.f, -4.f, 1.f, /* 0.8 < u < 1 */
0.f, 0.f, 0.f, 0.f, 0.f}; /* 1 < u */
/* ------------------------------------------------------------------------- */
#elif defined(QUINTIC_SPLINE_KERNEL)
/* ----------------------------------------------------------------------------- */
/* Coefficients for the kernel. */
#define kernel_name "Quintic spline (M6)"
#define kernel_degree 5
#define kernel_ivals 3
#define kernel_gamma 2.195775
#define kernel_constant 2187. * M_1_PI / 40.
static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
__attribute__((aligned(16))) = {
-10.f, 10.f, 0.f,
-2.2222222f, 0.f, 0.271604938f, /* 0 < u < 1/3 */
5.f, -15.f, 16.666667f,
-7.77777777f, 0.925925f, 0.209876543f, /* 1/3 < u < 2/3 */
-1.f, 5.f, -10.f,
10.f, -5.f, 1.f, /* 2/3 < u < 1. */
0.f, 0.f, 0.f,
0.f, 0.f, 0.f}; /* 1 < u */
/* ------------------------------------------------------------------------- */
#elif defined(WENDLAND_C2_KERNEL)
/* Coefficients for the kernel. */
......@@ -50,18 +86,50 @@ static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
#define kernel_degree 5
#define kernel_ivals 1
#define kernel_gamma 1.936492
#define kernel_constant 10.5 * M_1_PI
#define kernel_constant 21. * M_1_PI / 2.
static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
__attribute__((aligned(16))) = {
4.f, -15.f, 20.f, -10.f, 1.f, /* 0 < u < 1 */
0.f, 0.f, 0.f, 0.f, 0.f}; /* 1 < u */
/* ------------------------------------------------------------------------- */
#elif defined(WENDLAND_C4_KERNEL)
/* Coefficients for the kernel. */
#define kernel_name "Wendland C4"
#define kernel_degree 8
#define kernel_ivals 1
#define kernel_gamma 2.207940
#define kernel_constant 495. * M_1_PI / 32.
static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
__attribute__((aligned(16))) = {
11.666667f, -64.f, 140.f, -149.333333f, 70.f,
0.f, -9.3333333f, 0.f, 1.f, /* 0 < u < 1 */
0.f, 0.f, 0.f, 0.f, 0.f,
0.f, 0.f, 0.f, 0.f}; /* 1 < u */
/* ------------------------------------------------------------------------- */
#elif defined(WENDLAND_C6_KERNEL)
/* Coefficients for the kernel. */
#define kernel_name "Wendland C6"
#define kernel_degree 11
#define kernel_ivals 1
#define kernel_gamma 2.449490
#define kernel_constant 1365. * M_1_PI / 64.
static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
__attribute__((aligned(16))) = {
42.f * M_1_PI, -157.5f * M_1_PI, 210.f * M_1_PI, -105.f * M_1_PI,
0.f, 10.5f * M_1_PI, 0.f, 0.f,
0.f, 0.f, 0.f, 0.f};
32.f, -231.f, 704.f, -1155.f, 1056.f, -462.f,
0.f, 66.f, 0.f, -11.f, 0.f, 1.f, /* 0 < u < 1 */
0.f, 0.f, 0.f, 0.f, 0.f, 0.f,
0.f, 0.f, 0.f, 0.f, 0.f, 0.f}; /* 1 < u */
/* ----------------------------------------------------------------------------- */
/* ------------------------------------------------------------------------- */
#else
#error "A kernel function must be chosen in const.h !!"
/* ------------------------------------------------------------------------- */
#endif
/* Ok, now comes the real deal. */
......@@ -82,7 +150,8 @@ static float kernel_coeffs[(kernel_degree + 1) * (kernel_ivals + 1)]
#define kernel_nwneigh 4.0 * M_PI *kernel_gamma3 *kernel_eta3 / 3.0
/* Kernel self contribution (i.e. W(0,h)) */
#define kernel_root (kernel_coeffs[kernel_degree]) * kernel_igamma3
#define kernel_root \
(kernel_coeffs[kernel_degree]) * kernel_constant *kernel_igamma3
/**
* @brief Computes the kernel function and its derivative.
......@@ -97,7 +166,7 @@ __attribute__((always_inline)) INLINE static void kernel_deval(
float u, float *const W, float *const dW_dx) {
/* Go to the range [0,1[ from [0,H[ */
const float x = u * kernel_igamma;
const float x = u * (float)kernel_igamma;
/* Pick the correct branch of the kernel */
const int ind = (int)fminf(x * (float)kernel_ivals, kernel_ivals);
......@@ -114,8 +183,8 @@ __attribute__((always_inline)) INLINE static void kernel_deval(
}
/* Return everything */
*W = w * kernel_igamma3;
*dW_dx = dw_dx * kernel_igamma4;
*W = w * (float)kernel_constant * (float)kernel_igamma3;
*dW_dx = dw_dx * (float)kernel_constant * (float)kernel_igamma4;
}
/**
......
tests/test27cells.c
+ 9
− 8
View file @ 86ad36da
......@@ -61,12 +61,12 @@ struct cell *make_cell(size_t n, double *offset, double size, double h,
part->x[2] =
offset[2] +
size * (z + 0.5 + random_uniform(-0.5, 0.5) * pert) / (float)n;
// part->v[0] = part->x[0] - 1.5;
// part->v[1] = part->x[1] - 1.5;
// part->v[2] = part->x[2] - 1.5;
part->v[0] = random_uniform(-0.05, 0.05);
part->v[1] = random_uniform(-0.05, 0.05);
part->v[2] = random_uniform(-0.05, 0.05);
part->v[0] = part->x[0] - 1.5;
part->v[1] = part->x[1] - 1.5;
part->v[2] = part->x[2] - 1.5;
//part->v[0] = random_uniform(-0.05, 0.05);
//part->v[1] = random_uniform(-0.05, 0.05);
//part->v[2] = random_uniform(-0.05, 0.05);
part->h = size * h / (float)n;
part->id = ++(*partId);
part->mass = density * volume / count;
......@@ -209,7 +209,7 @@ void runner_doself1_density(struct runner *r, struct cell *ci);
int main(int argc, char *argv[]) {
size_t runs = 0, particles = 0;
double h = 1.12575, size = 1., rho = 1.;
double h = 1.2348, size = 1., rho = 1.;
double perturbation = 0.;
char outputFileNameExtension[200] = "";
char outputFileName[200] = "";
......@@ -257,7 +257,7 @@ int main(int argc, char *argv[]) {
"\nGenerates a cell pair, filled with particles on a Cartesian grid."
"\nThese are then interacted using runner_dopair1_density."
"\n\nOptions:"
"\n-h DISTANCE=1.1255 - Smoothing length"
"\n-h DISTANCE=1.2348 - Smoothing length in units of <x>"
"\n-m rho - Physical density in the cell"
"\n-s size - Physical size of the cell"
"\n-d pert - Perturbation to apply to the particles [0,1["
......@@ -268,6 +268,7 @@ int main(int argc, char *argv[]) {
/* Help users... */
message("Smoothing length: h = %f", h);
message("Kernel : %s", kernel_name);
message("Neighbour target: N = %f", kernel_nwneigh);
/* Build the infrastructure */
......
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