#include <stdio.h>
#include <math.h>

float chifit_ts(float tql,float tq,float tqh);

float chifit_ts(float tql,float tq,float tqh){
int i;
float qerr=2.2;
float tqq[3];
float xn;
float step;
int ifin,istep;
float chi2last,chi2min,chi2;
 float t;
  ifin=0;
  istep=0;
  chi2min=1.0e12;
  chi2last=1.0e12;
  t=0.0;
  step=50;
NEXT:
  istep=istep+1;
  if(istep>10000)goto FIN;
  chi2=0.0;
  tqq[0]=t*t*t*t*exp(-t/33.25);
  tqq[1]=(50.+t)*(50.+t)*(50.+t)*(50.+t)*exp((-50.-t)/33.25);
  tqq[2]=(100+t)*(100+t)*(100+t)*(100+t)*exp((-100.-t)/33.25);
  xn=(tqq[0]*tql+tqq[1]*tq+tqq[2]*tqh)/(tqq[0]*tqq[0]+tqq[1]*tqq[1]+tqq[2]*tqq[2]);
  chi2=(tql-xn*tqq[0])*(tql-xn*tqq[0])+(tq-xn*tqq[1])*(tq-xn*tqq[1])+(tqh-xn*tqq[2])*(tqh-xn*tqq[2]);
  // printf("     xn %f tqq %f %f %f  %d %d %d \n",xn,xn*tqq[0],xn*tqq[1],xn*tqq[2],tql,tq,tqh);
  chi2=chi2/(qerr*qerr);
  // printf(" t chi2 step  %f %f %f \n",t,chi2,step);
  if(chi2<chi2last){
    chi2last=chi2;
    if(chi2min>chi2)chi2min=chi2;
    t=t+step;
    goto NEXT;
  }
  if(step<0.0001){ifin=1;goto FIN;}
  t=t-2*step;
  step=step/2.;
  chi2last=1.0e12;
  goto NEXT;
FIN:
  // printf(" t %f \n",t);
  return t;
}