USW
AstrophysicsN-body SimulationExpertSeed

Infer cosmological parameters from simulated surveys

Run forward simulations and use simulation-based inference to recover cosmological parameters.

Dr. Johan Bergström
Cosmology Institute
Simulation-based inference in cosmology
Nature Astronomy · 2024
~3 days (HPC)
registered 2025-11-15
cosmologySBIN-body

End goal

Recover Ωm and σ8 within 5% with calibrated posteriors.

Overview

The agent runs N-body simulations across a parameter grid, builds summary statistics, and performs simulation-based inference to recover parameters with calibrated posteriors.

Tools allowed

1
GADGET-4 (N-body)·HPC

Workflow

2-step protocol

Each step is verified against the scientist's targets. Open any simulation to test it live.

  1. 1

    Simulate & summarize

    Step 1 / 2

    Run simulations and compute summary statistics.

    Protocol

    1. aRun N-body grid.
    2. bCompute power spectra / summaries.

    Targets

    Summary fidelity≥90% within tol
    Expected output

    Summary statistics across the parameter grid.

    Simulations · click to test

    output carries into step 2
  2. 2

    Inference

    Step 2 / 2

    Infer parameters with calibrated posteriors.

    Protocol

    1. aTrain the inference network.
    2. bValidate posterior calibration.

    Targets

    Parameter error≤5% rel.
    Posterior calibration≤5% coverage err
    Expected output

    Posteriors for Ωm and σ8.