fmm-examples/fmm_3d_block/fmm_3d_block.cpp
2022-02-16 11:57:36 +08:00

317 lines
8.8 KiB
C++

#include "iostream"
#include "cmath"
#include "vector"
#include "fstream"
#include "iomanip"
using namespace std;
struct point_3d
{
double x, y, z;
};
struct source : point_3d
{
double rad;
double slow;
};
struct grid_point : point_3d
{
int tag = 0; //0 = far away, 1 = close, 2 = active
double time = 1e+30;
double syn_time = 1e+30; //synthetic direct arrive time (only for error test)
double slow;
grid_point* neighbor[6] = {NULL,NULL,NULL,NULL,NULL,NULL}; //up down left right in out
};
typedef vector<grid_point> grid_point_array;
typedef vector<grid_point*> ptr_grid_point_array;
void update_heap(ptr_grid_point_array& a, int i, int n)
{
int iMax = i,
iLeft = 2 * i + 1,
iRight = 2 * (i + 1);
if (iLeft < n && a[iMax]->time < a[iLeft]->time) {
iMax = iLeft;
}
if (iRight < n && a[iMax]->time < a[iRight]->time) {
iMax = iRight;
}
if (iMax != i) {
grid_point* tmp = a[iMax];
a[iMax] = a[i];
a[i] = tmp;
update_heap(a, iMax, n);
}
return;
}
void heap_sort(ptr_grid_point_array& a, int n)
{
for (int i = (n - 1) / 2; i >= 0; i--) {
update_heap(a, i, n);
}
for (int i = n - 1; i > 0; --i) {
grid_point* tmp = a[i];
a[i] = a[0];
a[0] = tmp;
update_heap(a, 0, i);
}
return;
}
double dis_point_3d(point_3d a, point_3d b)
{
return sqrt((a.x-b.x)*(a.x-b.x) + (a.y-b.y)*(a.y-b.y) + (a.z-b.z)*(a.z-b.z));
}
void local_update(grid_point* point_ptr, double delta_h)
{
//solve a quadratic equation to get the trial time
/*
double a = 0, b = 0, c = -1.0 * pow(delta_h,2) * pow(point_ptr->slow,2);
for (int i = 0; i < 6; i++)
{
if (point_ptr->neighbor[i] != NULL && point_ptr->neighbor[i]->tag == 2)
{
a += 1.0;
b += -2.0*point_ptr->neighbor[i]->time;
c += pow(point_ptr->neighbor[i]->time,2);
}
}
*/
// a second order upwind difference scheme
double a = 0, b = 0, c = -4.0 * pow(delta_h,2) * pow(point_ptr->slow,2);
for (int i = 0; i < 6; i++)
{
if (point_ptr->neighbor[i] != NULL && point_ptr->neighbor[i]->tag == 2)
{
a += 4.0;
b += -8.0*point_ptr->neighbor[i]->time;
c += 4.0*pow(point_ptr->neighbor[i]->time,2);
if (point_ptr->neighbor[i]->neighbor[i] != NULL && point_ptr->neighbor[i]->neighbor[i]->tag == 2)
{
a += 5.0;
b += -16.0*point_ptr->neighbor[i]->time + 6.0*point_ptr->neighbor[i]->neighbor[i]->time;
c += 12.0*pow(point_ptr->neighbor[i]->time,2) - 8.0*point_ptr->neighbor[i]->time*point_ptr->neighbor[i]->neighbor[i]->time
+ pow(point_ptr->neighbor[i]->neighbor[i]->time,2);
}
}
}
double delta = b*b - 4.0*a*c; //in a upwind scheme, delta is always bigger than zero
point_ptr->time = min(point_ptr->time, 0.5*(sqrt(delta) - b)/a);
return;
}
void abnormal_slowness(grid_point_array& grid_recall, double ab_slow,double xmin, double xmax, double ymin, double ymax, double zmin, double zmax)
{
for (int i = 0; i < grid_recall.size(); i++)
{
if (grid_recall[i].x >= xmin && grid_recall[i].x <= xmax &&
grid_recall[i].y >= ymin && grid_recall[i].y <= ymax &&
grid_recall[i].z >= zmin && grid_recall[i].z <= zmax)
{
grid_recall[i].slow = ab_slow;
}
}
return;
}
int main(int argc, char const *argv[])
{
//set grid parameters
int xnum = 101;
int ynum = 51;
int znum = 51;
double xmin = 0;
double ymin = 0;
double zmin = 0;
double dh = 10;
//set source parameters
source init_source;
init_source.x = 50;
init_source.y = 250;
init_source.z = 250;
init_source.rad = 30;
init_source.slow = 1.0;
//output name
char ofilename[1024] = "out.msh";
//initialize grid
grid_point_array grid_3d;
grid_3d.resize(xnum*ynum*znum);
//down-left corner to up-right corner
for (int k = 0; k < znum; k++)
{
for (int i = 0; i < ynum; i++)
{
for (int j = 0; j < xnum; j++)
{
grid_3d[i*xnum+j+k*xnum*ynum].x = xmin + dh*j;
grid_3d[i*xnum+j+k*xnum*ynum].y = ymin + dh*i;
grid_3d[i*xnum+j+k*xnum*ynum].z = zmin + dh*k;
grid_3d[i*xnum+j+k*xnum*ynum].slow = init_source.slow;
if (k <= znum-2) grid_3d[i*xnum+j+k*xnum*ynum].neighbor[0] = &grid_3d[i*xnum+j+(k+1)*xnum*ynum];
if (k >= 1) grid_3d[i*xnum+j+k*xnum*ynum].neighbor[1] = &grid_3d[i*xnum+j+(k-1)*xnum*ynum];
if (j >= 1) grid_3d[i*xnum+j+k*xnum*ynum].neighbor[2] = &grid_3d[i*xnum+j-1+k*xnum*ynum]; //left
if (j <= xnum-2) grid_3d[i*xnum+j+k*xnum*ynum].neighbor[3] = &grid_3d[i*xnum+j+1+k*xnum*ynum]; //right
if (i <= ynum-2) grid_3d[i*xnum+j+k*xnum*ynum].neighbor[4] = &grid_3d[(i+1)*xnum+j+k*xnum*ynum]; //up
if (i >= 1) grid_3d[i*xnum+j+k*xnum*ynum].neighbor[5] = &grid_3d[(i-1)*xnum+j+k*xnum*ynum]; //down
//calculate synthetic direct arrive time
grid_3d[i*xnum+j+k*xnum*ynum].syn_time = dis_point_3d(grid_3d[i*xnum+j+k*xnum*ynum], init_source) * init_source.slow;
}
}
}
//add abnormal slowness here
//abnormal_slowness(grid_3d,1e+30,200,250,0,500,0,250);
//abnormal_slowness(grid_3d,1e+30,500,550,0,500,250,500);
//abnormal_slowness(grid_3d,1e+30,800,850,0,500,0,250);
ptr_grid_point_array close_node_ptr;
//initialize source nodes and close nodes;
for (int i = 0; i < xnum*ynum*znum; i++)
{
if (dis_point_3d(grid_3d[i],init_source) <= init_source.rad)
{
grid_3d[i].tag = 2;
grid_3d[i].time = dis_point_3d(grid_3d[i],init_source) * init_source.slow;
}
}
for (int i = 0; i < xnum*ynum*znum; i++)
{
if (grid_3d[i].tag == 2)
{
for (int j = 0; j < 6; j++)
{
if (grid_3d[i].neighbor[j] != NULL && grid_3d[i].neighbor[j]->tag == 0)
{
grid_3d[i].neighbor[j]->tag = 1;
close_node_ptr.push_back(grid_3d[i].neighbor[j]);
}
}
}
}
//calculate trial time for all close nodes
for (int i = 0; i < close_node_ptr.size(); i++)
{
local_update(close_node_ptr[i], dh);
}
//marching forward and updating the close nodes set
while (!close_node_ptr.empty())
{
// heap sort close nodes pointers to put the node first that has smallest time
heap_sort(close_node_ptr,close_node_ptr.size());
//change the first node's tag to 2 and update it's neighbor's time if it is not active
close_node_ptr[0]->tag = 2;
for (int i = 0; i < 6; i++)
{
if (close_node_ptr[0]->neighbor[i] != NULL && close_node_ptr[0]->neighbor[i]->tag == 0)
{
close_node_ptr[0]->neighbor[i]->tag = 1;
local_update(close_node_ptr[0]->neighbor[i], dh);
close_node_ptr.push_back(close_node_ptr[0]->neighbor[i]);
}
else if (close_node_ptr[0]->neighbor[i] != NULL && close_node_ptr[0]->neighbor[i]->tag == 1)
{
local_update(close_node_ptr[0]->neighbor[i], dh);
}
}
close_node_ptr.erase(close_node_ptr.begin());
}
//output Gmsh(.msh) file
ofstream outfile;
outfile.open(ofilename);
if (!outfile)
{
cerr << "file open error: " << ofilename << endl;
return -1;
}
outfile<<"$MeshFormat"<<endl<<"2.2 0 8"<<endl<<"$EndMeshFormat"<<endl<<"$Nodes"<<endl<<xnum*ynum*znum<<endl;
// set the first vertex index to 1 to avoid a display bug in Gmsh
for (int i = 0; i < xnum*ynum*znum; i++)
{
outfile << i + 1 << " " << setprecision(16) << grid_3d[i].x << " " << grid_3d[i].y << " " << grid_3d[i].z << endl;
}
outfile<<"$EndNodes"<<endl;
outfile<<"$Elements"<<endl<< (xnum-1)*(ynum-1)*(znum-1) <<endl;
for (int k = 0; k < znum-1; k++)
{
for (int i = 0; i < ynum-1; i++)
{
for (int j = 0; j < xnum-1; j++)
{
outfile << 1 + j + i*(xnum-1) + k*(xnum-1)*(ynum-1) <<" 5 1 0 ";
outfile << 1 + j + i*xnum + k*xnum*ynum << " "
<< 1 + j + i*xnum + k*xnum*ynum + 1 << " "
<< 1 + j + (i+1)*xnum + k*xnum*ynum + 1 << " "
<< 1 + j + (i+1)*xnum + k*xnum*ynum << " "
<< 1 + j + i*xnum + (k+1)*xnum*ynum << " "
<< 1 + j + i*xnum + (k+1)*xnum*ynum + 1 << " "
<< 1 + j + (i+1)*xnum + (k+1)*xnum*ynum + 1 << " "
<< 1 + j + (i+1)*xnum + (k+1)*xnum*ynum << endl;
}
}
}
outfile << "$EndElements"<< endl;
int tmp_node_num = 0;
for (int i = 0; i < xnum*ynum*znum; i++)
{
if (grid_3d[i].time < 1e+10)
tmp_node_num++;
}
outfile <<"$NodeData"<< endl;
outfile<<1<<endl<<"\"fmm arrive time (ms)\""<<endl<<1<<endl<<0.0<<endl
<<3<<endl<<0<<endl<<1<<endl<<tmp_node_num<<endl;
for (int i = 0; i < xnum*ynum*znum; i++)
{
if (grid_3d[i].time < 1e+10)
{
outfile << i + 1 << " " << setprecision(16) << grid_3d[i].time << endl;
}
}
outfile<<"$EndNodeData"<< endl;
outfile <<"$NodeData"<< endl;
outfile<<1<<endl<<"\"fmm - synthetic time (ms)\""<<endl<<1<<endl<<0.0<<endl
<<3<<endl<<0<<endl<<1<<endl<<tmp_node_num<<endl;
for (int i = 0; i < xnum*ynum*znum; i++)
{
if (grid_3d[i].time < 1e+10)
{
outfile << i + 1 << " " << setprecision(16) << grid_3d[i].time - grid_3d[i].syn_time << endl;
}
}
outfile<<"$EndNodeData"<< endl;
outfile <<"$NodeData"<< endl;
outfile<<1<<endl<<"\"node tag\""<<endl<<1<<endl<<0.0<<endl
<<3<<endl<<0<<endl<<1<<endl<<xnum*ynum*znum<<endl;
for (int i = 0; i < xnum*ynum*znum; i++)
{
outfile << i + 1 << " " << setprecision(16) << grid_3d[i].tag << endl;
}
outfile<<"$EndNodeData"<< endl;
outfile.close();
return 0;
}