C code to solve integral equations for primordial density perturbations
These are the codes I used to solve the evolution of primordial perturbations as described in arXiv:2105:?????.
There are two codes: iterative.c and boltzmann_it.c. They both evolve primordial perturbations until after recombination but before reionization. I am making these codes avaiable so anyone who is interested in details of the calculation described in the paper can find them. The code is not certified for cosmological analysis. The code uses a (poor implentation of) the UFA approximation; and uses an analytic approximation for the expansion rate at early times. It uses an ionization fraction calculated from from HyRec-.
In addition to iterative.c and boltzmann_it.c, there are a number of include files.
The output from HyRec-2 is in output_xe.dat. The input from a prior run of either code is in iterative.in.
I compiled both codes on my Mac laptop using
gcc -g iterative.c -lm -o iterative gcc -g boltzmann_it.c -lm -o boltzmann_it
although I think that my gcc is actually clang