Spindler-c V 1.0.0

The c version of the spindler (https://github.com/ruggero-valli/spindler) package, used to compute the long-term orbital evolution of a binary interacting with a circumbinary disk. The aim of this library is to facilitate the integration of the spindler functionalities into c or Fortran-based codes.

Based on Valli et al. 2024.

Find the python version at https://github.com/ruggero-valli/spindler

Requirements:

Spindler-c requires a working installation of librinterplate by Robert Izzard (https://gitlab.com/rob.izzard/librinterpolate).

You can use either meson/ninja or make to install spindler-c.

Installation with meson and ninja

Meson and ninja, from https://mesonbuild.com/ and https://ninja-build.org/ but best installed as system packages or with pip, are modern replacements for make which offer many options and improved performance.

To use meson and ninja to build a local version of the spindler-c shared libary without optimization, which is what you want to do if you are developing spindler-c, run

meson setup builddir 
ninja -C builddir

To build release version, with full optimization which is what you want to use spindler-c with other software, and install in the prefix $HOME i.e. shared library in $HOME/lib and include files in $HOME/include, run

meson setup builddir --buildtype=release --prefix=$HOME
ninja -C builddir install

To build a version of the spindler-c library which can run on generic (but similar, e.g. x86_64) platforms, which is useful on inhomogeneous computing clusters, run

meson setup builddir --buildtype=release -Dgeneric=true
ninja -C builddir

To build a version of the spindler-c library containing debugging information, e.g. for use with gdb, run

meson setup builddir --buildtype=debug
ninja -C builddir

To build a version of the spindler-c library for Valgrind testing run

meson setup builddir --buildtype=debug -Dvalgrind=true
ninja -C builddir

There are further options in the file meson.options, e.g. support for gprof, a build that attempts to be mathematically accurate across platforms and the use of Clang's address sanitizer.

To run the spindler-c tests:

meson setup builddir 
ninja -C builddir test_spindler
./builddir/test_spindler

Installation with make

git clone https://github.com/ruggero-valli/spindler-c.git
cd spindler-c
make

You can test wether the build was successful by running

make test

If the last line of the output is OK, then the build was successful and the program is working.

Description

spindler provides three alternative models of binary-disk interaction

• Siwek23: based on the simulations in

  • Siwek et al. 2023 (2023MNRAS.518.5059S)
  • Siwek et al. 2023 (2023MNRAS.522.2707S)

  It is defined for eccentricity between 0 and 0.8, and mass ratio between 0.1 and 1.

• DD21: based on the simulations in

  • D'Orazio and Duffell 2021 (2021ApJ...914L..21D)

  It is defined for eccentricity between 0 and 0.8, and mass ratio equal to 1.

• Zrake21: based on the simulations in

  • Zrake et al. 2021 (2021ApJ...909L..13Z)

  It is defined for eccentricity between 0 and 0.8, and mass ratio equal to 1.

Documentation of the python version

https://spindler.readthedocs.io/

The spindler-c is similar to the corresponding python package. It provides functions to compute the derivatives of the orbital parameters, exactly as in the python version.

It doesn't include the functionality to integrate these derivatives.

Example usage

#include <stdio.h>
#include <stdlib.h>
#include "spindler.h"

int main(){

    // Choose the model. It must be either "Siwek23", "Zrake21" or "DD21".
    char* model_name = "Siwek23";

    // Initialize the library
    struct spindler_data_t* spindler_data = calloc(1, sizeof(struct spindler_data_t));
    int err;
    err = spindler_init(model_name, spindler_data);
    if (err != SPINDLER_NO_ERROR){
        return 1;
    }


    // Pick a mass ration and an eccentricity
    double q=0.5, e=0.5;

    // Compute the derivatives of the orbital parameters at the given
    // eccentricity and mass ratio.
    double Dq, De, Da, DE, DJ;
    Dq = spindler_get_Dq(q, e, spindler_data);
    De = spindler_get_De(q, e, spindler_data);
    Da = spindler_get_Da(q, e, spindler_data);
    DE = spindler_get_DE(q, e, spindler_data);
    DJ = spindler_get_DJ(q, e, spindler_data);

    // Print the results
    printf("Dq: %lf, De: %lf, Da: %lf, DE: %lf, DJ: %lf\n", Dq, De, Da, DE, DJ);

    // Free the allocated structures
    spindler_free_data(spindler_data);
    free(spindler_data);
    return 0;
}