function fit1a(n,x) c======================================================== c Fitness function for linear least squares problem c (Sect. 5.2) c======================================================== implicit none common/data/ f(200),t(200),sigma,ndata integer n,i,ndata real x(n),fit1a,f,t,sigma,a,b,sum c---------- 1. rescale input variables: a=x(1)*10. b=x(2)*100. c---------- 2. compute chi**2 sum=0. do 1 i=1,ndata sum=sum+ ( (a*t(i)+b-f(i))/sigma )**2 1 continue c---------- 3. define fitness fit1a=1./sum return end