# Selected Topics in Numerical Methods for Cosmology

## TL;DR

This paper reviews the development of numerical methods and software libraries for cosmological data analysis, emphasizing challenges and differences in implementation as precision requirements increase.

## Contribution

It provides a comprehensive review of existing cosmological software, discusses implementation challenges, and compares different codes' approaches to high-precision cosmological analysis.

## Key findings

- Identification of challenges in multi-probe cosmological software development
- Discussion on numerical definitions and implementation differences in codes
- Analysis of advantages and disadvantages of various public cosmological codes

## Abstract

The large amount of cosmological data already available (and in the near future) makes necessary the development of efficient numerical codes. Many software products have been implemented to perform cosmological analyses considering one or few probes. The need of multi-task software is rapidly increasing, in order to combine numerous cosmological probes along with their specificity (e.g., astrophysical descriptions and systematic errors). In this work we mention some of these libraries, bringing out some challenges they will face in the few-percent error era (on the cosmological parameters). We review some concepts of the standard cosmological model, and examine some specific topics on their implementation, bringing, for example, the discussion on how some quantities are numerically defined in different codes. We also consider implementation differences between public codes, mentioning their advantages/disadvantages.