Inflatox - multifield inflation consistency conditions in python

Inflatox provides utilities to compute slow-roll parameters and turn-rates for two-field inflation models, based on the consistency condition from Generalised consistency condition first presented in Anguelova & Lazaroiu (2023)¹ and later generalised for the purposes of this package in Wolters, Iarygina & Achúcarro (2024)² arXiv:2405.11628. The consistency conditions can be used in a parameter sweep of a two-field model to find possible inflation trajectories.

Features

• symbolic solver for components of the Hesse matrix of an inflationary model with non-canonical kinetic terms, powered by sympy.
• transpiler to transform sympy expressions into executable compiled (C) code.
• (experimental) support for special function transpilation using the GSL
• built-in multithreaded rust module for high-performance calculations of consistency conditions that interfaces directly with numpy and python.
• utilities for performing parameter sweeps.
• extendability: inflatox' exposes a python interface to calculate any intermediate quantity, which can be used to extend it with additional consistency conditions.
• no need to read, write or compile any rust or C code manually (this is all done automatically behind the scenes).
• no system dependencies, everything needed to run the package can be automatically installed by pip.

Installation and Dependencies

The latest version of inflatox can be installed using pip:

pip install inflatox

Inflatox can be updated using:

pip install --upgrade inflatox

Example programme

The following code example shows how inflatox can be used to calculate the potential and components of the Hesse matrix for a two-field hyperinflation model.

import inflatox
import numpy as np
import sympy as sp

# define model
r, θ, m = sp.symbols("r θ m")
fields = [r, θ]

V = (1 / 2 * m**2 * (θ**2 - 2 / (3 * r**2))).nsimplify()
g = [[0.5, 0], [0, 0.5 * r**2]]

# symbolic calculation
model = inflatox.InflationModelBuilder.new(fields, g, V).build()

# run the compiler
compiled_model = inflatox.Compiler(model).compile()
compiled_model.print_sym_lookup_table()

# evaluate the compiled potential and Hesse matrix at the point x
from inflatox.consistency_conditions import GeneralisedAL

params = np.array([1.0])
x = np.array([2.0, -2.0])

anguelova_condition = GeneralisedAL(compiled_model)

potential = anguelova_condition.calc_V(x, params)
hesse_mtrx = anguelova_condition.calc_H(x, params)
print(potential, hesse_mtrx)

# evaluate the consistency condition over a range of field-space coords (extent)
extent = [0.0, 2.5, 0.0, np.pi]
consistency_condition, epsilon_V, epsilon_H, eta_H, delta, omega = (
    anguelova_condition.complete_analysis(params, *extent)
)

Special function support

Inflatox features (experimental) support for transpiling special functions from scipy to C using the GSL library. The GSL (GNU Scientific Library) is not packaged together with inflatox due to its conflicting license. Inflatox merely generates code that calls GSL functions, you must still provide the headers and compiled shared libraries (libgsl and libgslcblas) yourself.

If you intend on using this feature, make sure that:

• The GSL is installed and can be found
• GSLCBLAS is installed and can be found
• The GSL headers are installed and can be found

Check out the documentation of the Compiler class for a list of currently supported special functions, and the docs.md file for more technical details. If you are experiencing any issues with the gsl feature (or if a special function you need is missing), please open an issue on github or contact the authors.

Supported Architectures

The combinations of OS and CPU architecture listed down below have pre-compiled binary distributions of inflatox available via PiPy. If your arch is not listed here, you will have to compile inflatox manually.

• Intel/AMD x86/i686 (32 bit)
  • linux/gnu (glibc >= 2.17, kernel >= 3.2)
• Intel/AMD x86_64/amd64 (64 bit)
  • linux/gnu (glibc >= 2.17, kernel >= 3.2)
  • windows 10+
  • macOS 10.12+ / Sierra+
• ARM aarch64 (64 bit)
  • linux/gnu (glibc >= 2.17, kernel >= 4.1)
  • macOS 11.0+ / Big Sur+

License

[!CAUTION] Inflatox is explicitly not licensed under the dual Apache/MIT license common to the Rust ecosystem. Instead it is licensed under the terms of the European Union Public License v1.2.

Inflatox is a science project and embraces the values of open science and free and open software. Closed and paid scientific software suites hinder the development of new technologies and research methods, as well as diverting much- needed public funds away from researchers to large publishing and software companies.

See the LICENSE.md file for the EUPL text in all 22 official languages of the EU, and LICENSE-EN.txt for a plain text English version of the license.

References and footnotes