MassFunc

A Python package for cosmological mass function calculations, including Press-Schechter, Sheth-Tormen mass functions, star formation rate density calculations, and more.

Features

• Cosmological calculations: Support for various cosmological parameters and models
• Mass function calculations: Implements Press-Schechter and Sheth-Tormen mass functions
• Star formation rate density: Calculate SFRD with customizable parameters
• Collapse fraction: Tools for calculating collapse fractions
• Efficient interpolation: Built-in interpolation for fast calculations

Installation

From PyPI (recommended)

pip install massfunc

From source

git clone https://github.com/SOYONAOC/MassFunction.git
cd massfunc
pip install -e .

Quick Start

import massfunc

# Create a mass function calculator with default cosmology
mf = massfunc.Mass_func(ns=0.965, sigma8=0.811, h=0.674, omegam=0.315)

# Setup interpolation for faster calculations
mf.sigma2_interpolation_set()
mf.dsig2dm_interpolation_set()

# Calculate mass function at z=0 for a range of masses
import numpy as np
masses = np.logspace(10, 15, 100)  # 10^10 to 10^15 solar masses
z = 0.0

# Press-Schechter mass function
dndm_ps = mf.dndmps(masses, z)

# Sheth-Tormen mass function
dndm_st = mf.dndmst(masses, z)

# Star formation rate density
sfrd = massfunc.SFRD(ns=0.965, sigma8=0.811)
rho_sfr = sfrd.rhosfr(1e4, 1e8, z)

Classes and Methods

CosmologySet

Base class for cosmological parameters:

• h: Dimensionless Hubble parameter
• omegam: Matter density parameter
• omegab: Baryon density parameter
• omegalam: Dark energy density parameter

Mass_func

Main class for mass function calculations:

• sigma2(): Variance of density field
• dndmps(): Press-Schechter mass function
• dndmst(): Sheth-Tormen mass function
• dndmeps(): Extended PS mass function

Collapse_fraction

Calculate collapse fractions:

• fcoll(): Collapse fraction
• dfcolldz(): Derivative of collapse fraction with redshift

SFRD

Star formation rate density calculations:

• rhosfr(): Star formation rate density
• fstar(): Star formation efficiency
• fduty(): Duty cycle

Dependencies

• numpy >= 1.18.0
• scipy >= 1.5.0
• astropy >= 4.0
• matplotlib >= 3.0.0
• sympy >= 1.6.0
• joblib >= 1.0.0

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please feel free to submit a Pull Request.

Citation

If you use this package in your research, please cite:

@software{massfunc,
  author = {Your Name},
  title = {MassFunc: A Python package for cosmological mass function calculations},
  url = {https://github.com/yourusername/massfunc},
  version = {0.1.0},
  year = {2025}
}

Support

If you encounter any issues or have questions, please file an issue on the GitHub repository.

Update log

Version 0.1.1

• Added EPS (Extended Press-Schechter) collapse fraction calculation
• New method fcolleps() in Collapse_fraction class
• Enhanced collapse fraction functionality