[Bug]: Investigate precision and out-of-bounds failures

[harryswift01]

Bug Report

Some calculations may require higher numerical precision, while other failures may be caused by values or indexes moving outside their valid range.

We need reproducible evidence before changing precision across the codebase.

To Reproduce

Add known cases showing unstable results, suspected quad-precision requirements, invalid indexes, or out-of-range values.

YAML configuration

# Add the configuration here.

CLI command used

# Add the command here.

Actual output

Observed behaviour may include unstable values, platform-dependent results, crashes, or incorrect output without a clear error.

Expected output

SIST should use sufficient precision where it is genuinely needed and should catch invalid ranges before unsafe access occurs.

Proposed Work

• Reproduce known precision failures.
• Compare standard and quad precision.
• Measure scientific and performance differences.
• Check compiler and platform support.
• Review array, table, and calculated-index access.
• Add bounds checks and safe failure behaviour.
• Add regression tests.
• Document platform limitations.

Done When

• Precision concerns have reproducible cases where possible.
• The benefit and cost of increased precision are measured.
• Precision changes are targeted and justified.
• Known out-of-bounds cases are detected safely.
• Users receive a clear error for invalid ranges.
• Scientific changes have been reviewed.