ADR 0008 — Reject IFT from core

0008 — Reject Information Field Theory from core, adopt NIFTy.re at inference layer¶

Context¶

As the jaxstro ecosystem grew, a proposal emerged to include Information Field Theory (IFT) capabilities in the core. IFT is a powerful statistical framework used in some astrophysics applications, and the question was whether to include it in jaxstro or keep it external.

Decision¶

Reject IFT from jaxstro core. If/when needed, adopt NIFTy.re as an upper-layer inference library (not part of the foundation). Seed a future ADR for this decision.

Rationale¶

• Thin-foundation principle: IFT is a heavy framework that violates the thin-foundation posture (see ADR-0001). Adding it would import significant complexity and dependencies into the foundation that every downstream package inherits.

• Specialized domain need: IFT is not generic infrastructure; it is a specialized inference method for specific applications. It belongs in domain-specific layers (e.g., a future astrophysics-inference package), not the foundation.

• No foundational dependency: jaxstro does not itself need IFT; consumers that want it can pull in NIFTy.re independently.

• Maintainability: IFT’s complexity and evolution would create maintenance burden on the foundation layer, slowing releases and decoupling version cycles.