void calc_kpkm_yields(){
  //gROOT->ProcessLine(".L /work/halld2/home/staylor/src/macros/calc_kpkm_yield.C");
  double phi_kpkm[45],dphi_kpkm[45]; 
  for (unsigned int i=1;i<46;i++){
    unsigned int k=i-1;
    double yield;
    double unc;
    calc_kpkm_yield(i,yield,unc); 
    phi_kpkm[k]=yield;
    dphi_kpkm[k]=unc;
  }
  ofstream fout2("phi_kpkm_yields.dat");
  for (int j=0;j<45;j++){
    fout2 << 2.9+0.2*j << " " <<phi_kpkm[j] << " " << dphi_kpkm[j] << endl;
  }
  fout2.close();

  double egamma[45];
  for (int j=0;j<45;j++) egamma[j]=2.9+0.2*j;
  TGraphErrors *g1=new TGraphErrors(45,egamma,phi_kpkm,0,dphi_kpkm);
  g1->Draw();



}