First Simulation

A narrated walkthrough of a real CosmicGrain run — not just proving the build works, but understanding the choices behind it. This page assumes you've already completed Quick Start.

Generating initial conditions

Use one of the accepted MUSIC2 files described in Zoom Setup. A dust-enabled IC begins with gas and dark matter but an empty PartType6; stellar feedback creates dust during evolution.

A minimal .param file

Start from a maintained production parameter file rather than reconstructing one from this page. For an inexpensive validation run:

1. use a \(512^3\)-equivalent IC;
2. shorten the output list while retaining early, first-star, first-dust, and late checkpoints;
3. keep the selected physics configuration unchanged;
4. enable restart writing; and
5. archive the parameter file with the output.

Validation sequence

After startup, verify increasingly demanding milestones:

1. evolution before star formation, with no stars or dust;
2. first star formation and element enrichment;
3. first SNII/LRN dust creation;
4. delayed AGB enrichment and dust creation;
5. restart continuity across an active feedback interval; and
6. whole-box mass, element, and dust-composition closure at the final output.

The accepted Halo 295/\(512^3\) benchmark is summarized in Validation.