sig2posSe.c
No OneTemporary
Actions

Subscribers

None

File Metadata

	#include<stdio.h>
	#include<math.h>
	#include<fonction.h>
	#include<constant.h>
	#include<dimension.h>
	#include<structure.h>

	/****************************************************************/
	/* nom: sig2posSe */
	/* auteur: Eric Jullo */
	/* date: 01/07 */
	/* place: Marseille */
	/****************************************************************
	* Assuming that the deflection angle is linear between the observed
	* and predicted image, it is possible to analytically relate the
	* image plane chi2 to the source plane chi2.
	*
	* chi2_img = (xi - xiobs) = (xs - bar(xs)) / (1 - d2xxPhi)
	*
	* The observational uncertainties are the image ellipticities a & b.
	*
	* Global variables used :
	*
	*/
	void sig2posSe(struct galaxie multi, double sigx2, double *sigy2)
	{

	struct matrix grad2;

	grad2 = e_grad2_gal(multi, NULL);
	grad2.a /= multi->dos;
	grad2.c /= multi->dos;
	sigx2 = (1. - grad2.a) (1. - grad2.a) * multi->E.a * multi->E.a;
	sigy2 = (1. - grad2.c) (1. - grad2.c) * multi->E.b * multi->E.b;
	}