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chi_computation.cpp
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Thu, Dec 12, 01:20

chi_computation.cpp
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//
#include <string.h>
#include "structure_hpc.hpp"
#include "delense_CPU_utils.hpp"
#ifdef __WITH_MPI
#include <mpi.h>
#include "mpi_check.h"
#endif
void
chi_computation(double* chi, int* images_found, int* numimagesfound, struct point* imagesposition, const int *nimages_strongLensing, const galaxy* images, const int nsets)
{
int nimagesfound [nsets][MAXIMPERSOURCE]; // number of images found from the theoretical sources
struct point tim [MAXIMPERSOURCE]; // theoretical images (computed from sources)
int index = 0;
//
for( int source_id = 0; source_id < nsets; source_id ++)
{
unsigned short int nimages = nimages_strongLensing[source_id];
//
//______________________Initialisation______________________
//
//for (unsigned short int i = 0; i < nimages; ++i)
// nimagesfound[source_id][i] = 0;
memset(&nimagesfound[source_id][0], 0, nimages*sizeof(int));
//
//for( unsigned short int image_id = 0; image_id < nimages; image_id++)
//{
//#endif //collapsing
//
double image_dist[MAXIMPERSOURCE];
//
//printf(" Source %d, number of images found %d\n", source_id, numimagesfound[source_id]);
//
struct point image_position;
int image_index;
//
for (int ii = 0; ii < /*loc*/numimagesfound[source_id]; ++ii)
{
//
//
int image_index = 0;
//
image_position = imagesposition[source_id*MAXIMPERSOURCE + ii];
image_dist[0] = mychi_dist(image_position, images[index + 0].center); // get the distance to the real image
for(int i = 1; i < nimages_strongLensing[source_id]; i++)
{ // get the distance to each real image and keep the index of the closest real image
image_dist[i] = mychi_dist(image_position, images[index + i].center);
if (image_dist[i] < image_dist[image_index])
{
image_index = i;
}
}
//
// we should exit loops here
//
// p1_time += myseconds();
//
int skip_image = 0;
// Sometimes due to the numerical errors at the centerpoint,
// for SIE potentials an additional image will appear at the center of the Potential.
// This is due to the fact that it is not possible to simulate an infinity value
// at the center correctly, Check that sis correspond to Nlens[0]
/*
for (int iterator = 0; iterator < runmode->Nlens[0]; ++iterator)
{
if ( fabs(image_position.x - lens[0].position_x[iterator]) <= dx/2. and fabs(image_position.y - lens[0].position_y[iterator]) <= dx/2.)
{
skip_image = 1;
printf("WARNING: You are using SIE potentials. An image to close to one of the potential centers has been classified as numerical error and removed \n");
}
}*/
//printf("%d %d %d %d\n", x_id, y_id,thread_found_image, skip_image);
if (!skip_image)
{
//#pragma omp atomic
(*images_found)++;
struct point temp;
//printf(" source %d, image %d, index %d, Images found: %d\n", source_id, image_id, image_index, nimagesfound[source_id][image_id][image_index]);
//checking whether a closest image has already been found
if (nimagesfound[source_id][image_index] == 0)
{ // if no image found up to now
//image position is allocated to theoretical image
//#pragma omp critical
tim[image_index] = image_position;
//#pragma omp atomic
nimagesfound[source_id][image_index]++;
}
else if (nimagesfound[source_id][image_index] > 0)
{ // if we have already found an image
// If the new image we found is closer than the previous image
//printf(" tim2: %f %f\n", image_dist[image_index], mychi_dist(images[index + image_index].center, tim[image_id][image_index]));
if (image_dist[image_index] < mychi_dist(images[index + image_index].center, tim[image_index]))
{
temp = tim[image_index]; // we store the position of the old image in temp
//#pragma omp critical
tim[image_index] = image_position; // we link the observed image with the image we just found
//printf("tim2 %d %d = %f %f\n", image_id, image_index, image_position.x, image_position.y);
}
else
{
temp = image_position; // we store the position of the image we just found in temp
}
// initialising second_closest_id to the highest value
// Loop over all images in the set except the closest one
// and initialize to the furthest away image
int second_closest_id = 0;
for (int i = 1; i < nimages_strongLensing[source_id] && (i != image_index); i++)
{
if(image_dist[i] > image_dist[second_closest_id]) second_closest_id=i;
}
///////////////////////////////////////////////////////////////
// Loop over all images in the set that are not yet allocated to a theoretical image
// and allocate the closest one
// we search for an observed image not already linked (nimagesfound=0)
for(int i = 0; i < nimages_strongLensing[source_id] && nimagesfound[source_id][i] == 0; i++)
{
if(image_dist[i] < image_dist[second_closest_id])
{
second_closest_id = i;
// im_index value changes only if we found a not linked yet image
image_index = i;
//printf("tim3 %d %d = %f %f\n", image_id, image_index, temp.x, temp.y);
//#pragma omp critical
tim[image_index] = temp; // if we found an observed and not already linked image, we allocate the theoretical image temp
}
}
// increasing the total number of images found (If we find more than 1 theoretical image linked to 1 real image,
// these theoretical
//#pragma omp atomic
nimagesfound[source_id][image_index]++;
// images are included in this number)
}
}
//#pragma omp atomic
//loc_images_found++;
//thread_found_image = 0; // for next iteration
}
//
//}
//#pragma omp barrier
//____________________________ end of image loop
//
//____________________________ computing the local chi square
//
double chiimage;
//
int _nimages = nimages_strongLensing[source_id];
//
for( int iter = 0; iter < _nimages; iter++)
{
int i = iter;
//int i=iter/nimages_strongLensing[source_id];
//int j=iter%nimages_strongLensing[source_id];
//printf("nimagesfound %d %d = %d\n", i, j, nimagesfound[i][j]);
//if(i != j)
//{
if(nimagesfound[source_id][i] > 0)
{
double pow1 = images[index + i].center.x - tim[i].x;
double pow2 = images[index + i].center.y - tim[i].y;
//
//chiimage = pow(images[index + j].center.x - tim[i][j].x, 2) + pow(images[index + j].center.y - tim[i][j].y, 2); // compute the chi2
chiimage = pow1*pow1 + pow2*pow2; // compute the chi2
//printf("%d %d = %.15f\n", i, j, chiimage);
(*chi) += chiimage;
}
else
if(nimagesfound[source_id][i] == 0)
{
// If we do not find a correpsonding image, we add a big value to the chi2 to disfavor the model
(*chi) += 1000.*nimages_strongLensing[source_id];
//printf(" source_id = %d, image number = %d has not found an image, chi = %f\n", source_id, i, *chi);
}
//}
}
//
//____________________________ end of computing the local chi square
//
//printf("%d: chi = %.15f\n", source_id, *chi);
/*
for (int i=0; i < nimages_strongLensing[source_id]; ++i){
for (int j=0; j < nimages_strongLensing[source_id]; ++j){
printf(" %d",nimagesfound[i][j]);
}
printf("\n");
}*/
//Incrementing Index: Images already treated by previous source_id
index += nimages_strongLensing[source_id];
}
}

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