https://github.com/williamjameshandley/primordial

python code for solving cosmological inflation
https://github.com/williamjameshandley/primordial

Last synced: 5 days ago
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python code for solving cosmological inflation

• Host: GitHub
• URL: https://github.com/williamjameshandley/primordial
• Owner: williamjameshandley
• License: gpl-3.0
• Created: 2018-09-25T16:47:09.000Z (about 6 years ago)
• Default Branch: master
• Last Pushed: 2018-10-12T11:30:08.000Z (about 6 years ago)
• Last Synced: 2024-09-14T22:26:56.008Z (about 2 months ago)
• Language: Python
• Size: 234 KB
• Stars: 4
• Watchers: 3
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.rst
  • Contributing: CONTRIBUTING.md
  • License: LICENSE
  • Code of conduct: CODE_OF_CONDUCT.md

Awesome Lists containing this project

README

        
========================================

primordial: inflationary equation solver

========================================

:primordial: inflationary equation solver

:Author: Will Handley

:Version: 0.0.14

:Homepage: https://github.com/williamjameshandley/primordial

:Documentation: http://primordial.readthedocs.io/

.. image:: https://travis-ci.org/williamjameshandley/primordial.svg?branch=master

   :target: https://travis-ci.org/williamjameshandley/primordial

   :alt: Build Status

.. image:: https://codecov.io/gh/williamjameshandley/primordial/branch/master/graph/badge.svg

   :target: https://codecov.io/gh/williamjameshandley/primordial

   :alt: Test Coverage Status

.. image:: https://badge.fury.io/py/primordial.svg

   :target: https://badge.fury.io/py/primordial

   :alt: PyPi location

.. image:: https://readthedocs.org/projects/primordial/badge/?version=latest

   :target: https://primordial.readthedocs.io/en/latest/?badge=latest

   :alt: Documentation Status

.. image:: https://zenodo.org/badge/150298714.svg

   :target: https://zenodo.org/badge/latestdoi/150298714

   :alt: Permanent DOI for this release

Description

===========

``primordial`` is a python package for solving cosmological inflationary equations.

It is very much in beta stage, and currently being built for research purposes.

Example Usage

=============

Plot Background evolution

-------------------------

.. code:: python

    import numpy

    import matplotlib.pyplot as plt

    from primordial.solver import solve

    from primordial.equations.inflation_potentials import ChaoticPotential

    from primordial.equations.t.inflation import Equations, KD_initial_conditions

    from primordial.equations.events import Inflation, Collapse

    

    fig, ax = plt.subplots(3,sharex=True)

    for K in [-1, 0, +1]:

         m = 1

         V = ChaoticPotential(m)

         equations = Equations(K, V)

    

         events= [Inflation(equations),                    # Record inflation entry and exit 

                  Inflation(equations, -1, terminal=True), # Stop on inflation exit

                  Collapse(equations, terminal=True)]      # Stop if universe stops expanding

    

         N_p = -1.5

         phi_p = 23

         t_p = 1e-5

         ic = KD_initial_conditions(t_p, N_p, phi_p)

         t = numpy.logspace(-5,10,1e6)

    

         sol = solve(equations, ic, t_eval=t, events=events)

    

         ax[0].plot(sol.N(t),sol.phi(t))

         ax[0].set_ylabel(r'$\phi$')

    

         ax[1].plot(sol.N(t),sol.H(t))

         ax[1].set_yscale('log')

         ax[1].set_ylabel(r'$H$')

    

         ax[2].plot(sol.N(t),1/(sol.H(t)*numpy.exp(sol.N(t))))

         ax[2].set_yscale('log')

         ax[2].set_ylabel(r'$1/aH$')

         

    ax[-1].set_xlabel('$N$')

|image0|

Plot mode function evolution

----------------------------

.. code:: python

    import numpy

    import matplotlib.pyplot as plt

    from primordial.solver import solve

    from primordial.equations.inflation_potentials import ChaoticPotential

    from primordial.equations.t.mukhanov_sasaki import Equations, KD_initial_conditions

    from primordial.equations.events import Inflation, Collapse, ModeExit

    fig, axes = plt.subplots(3,sharex=True)

    for ax, K in zip(axes, [-1, 0, +1]):

        ax2 = ax.twinx()

        m = 1

        V = ChaoticPotential(m)

        k = 100

        equations = Equations(K, V, k)

        events= [

                Inflation(equations),                    # Record inflation entry and exit

                Collapse(equations, terminal=True),      # Stop if universe stops expanding

                ModeExit(equations, +1, terminal=True, value=1e1*k)   # Stop on mode exit

                ]

        N_p = -1.5

        phi_p = 23

        t_p = 1e-5

        ic = KD_initial_conditions(t_p, N_p, phi_p)

        t = numpy.logspace(-5,10,1e6)

        sol = solve(equations, ic, t_eval=t, events=events)

        N = sol.N(t)

        ax.plot(N,sol.R1(t), 'k-')

        ax2.plot(N,-numpy.log(sol.H(t))-N, 'b-')

        ax.set_ylabel('$\mathcal{R}$')

        ax2.set_ylabel('$-\log aH$')

        ax.text(0.9, 0.9, r'$K=%i$' % K, transform=ax.transAxes)

    axes[-1].set_xlabel('$N$')

|image1|

.. |image0| image:: https://raw.githubusercontent.com/williamjameshandley/primordial/master/figures/background.png

.. |image1| image:: https://raw.githubusercontent.com/williamjameshandley/primordial/master/figures/ms.png 

To do list

==========

Eventually would like to submit this to `JOSS `_. Here are things to do before then:

Cosmology

---------

* Slow roll initial conditions

* add :math:`\eta` as independent variable

* add :math:`\phi` as independent variable

Code

----

* Documentation

* Tests

   * 100% coverage

   * interpolation