double fdeltatime(double z1, double z2) {
double temp;
double dz=0.001,z;
double deltat;
int n,i;
if (z1 > z2) {
temp=z1;
z1=z2;
z2=temp;
}
n=(int)round((z2-z1)/dz);
dz=(z2-z1)/n;
deltat=0.;
for (i=0;i<n;i++) {
z=z1+dz/2.+dz*i;
deltat+=fabs(dtdz(z)); // just in case there is a negative sign - results in seconds
}
deltat*=dz;
return deltat;
}
/* comoving distance (in cm) per unit redshift */
double drdz(float z){
return (1.0+z)*C*dtdz(z);
}
/* in proper Mpc */
double d_L_derivs(double z, void * params){
return (1+z) * fabs(dtdz(z));
}
/* Comoving volume (in Mpc^3) probed by past light cone, per z interval */
double dVdz(float z){
double d;
d = d_L(z);
return 4*PI*d*d*C*fabs(dtdz(z)) / (1+z) / CMperMPC;
}
double ddtdz(double z, void * params) {
return dtdz(z);
}
