% Hints for HW4 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %>>>>> Integration % this command integrates "deta" from a1 to a2 chi = quad(@(x) deta(x,par),a1,a2); % note that you have to define your own funtion "deta(x,par) in the usual % manner. This line is more complicated than the simplest use of "quad" so % that the function "deta" can have two paramters. % my function "deta" looks like this (in a separate file): function [deta_ans] = deta(a,par) % the value of d eta (conformal time) in Mpc deta_ans = 1./(a.^2.*HinvMpc(a,par)); % of course to use this I need to define the function HinvMpc as well. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% %>>>>>> Minimizing % to minimize chisq as a function of muoff I use the following lines muoff = fminsearch(@(x) chisq(x,par), 0); chisqfinal = chisq(muoff,par) % the function chisq has to be constructed separately