Setting custom simulation parameters

Setting custom simulation parameters (How-to)

Goal

Create simulation parameters for a Star (or Cluster) run, and optionally restrict the ages saved in output tracks using AgesOut. This overrides MORS default simulation parameters.

Prerequisites

Make sure MORS and stellar evolution data are installed:

pip install fwl-mors
mors download all

Step 1: Start from the default parameter set

Create a parameter dictionary identical to the internal defaults (paramsDefault in parameters.py):

import mors
params = mors.NewParams()

This gives you a normal Python dictionary you can edit.

Step 2: Change one or more parameters

Option A: edit the dictionary after creation

import mors
params = mors.NewParams()

params["param1"] = 1.5
params["param2"] = 2.5

Option B: set values when calling NewParams (recommended)

import mors
params = mors.NewParams(param1=1.5, param2=2.5)

Step 3: Pass the parameter dictionary into `Star` (or `Cluster`)

import mors
star = mors.Star(Mstar=1.0, Omega=10.0, params=params)

(Use the same params= keyword when creating a mors.Cluster.)

Step 4: Discover available parameters

To print a complete list of parameters (and their meanings/values as exposed by MORS):

import mors
mors.PrintParams()

You can also inspect the source file parameters.py in your MORS installation.

Step 5: Restrict output ages with `AgesOut` (optional)

By default, MORS computes tracks on its internal age grid. If you only need values at specific ages, set AgesOut so the saved tracks contain only those ages plus the starting age (1 Myr).

Single age

import mors
star = mors.Star(Mstar=1.0, Omega=10.0, AgesOut=100.0)  # Myr

Multiple ages

import numpy as np
import mors

ages = np.array([100.0, 200.0, 300.0, 400.0])  # Myr (ascending)
star = mors.Star(Mstar=1.0, Omega=10.0, AgesOut=ages)

Notes: - The simulation ends at the largest age in AgesOut. - Provide AgesOut in ascending order. - If you later call interpolating helpers like star.Lx(Age) at arbitrary ages, results can be inaccurate if AgesOut is too sparse. - Very large AgesOut grids can slow down calculations significantly.

Common pitfalls

AgesOut is in Myr.
If you intend to query many arbitrary ages later, prefer the default age grid (don’t over-thin AgesOut).

Setting custom simulation parameters