DCIEM Decompression Model (1973) — Fortran IV transcription

This repository contains a faithful transcription of the DCIEM (Defence and Civil Institute of Environmental Medicine) decompression model programs described in the 1973 report “Digital Computation of Decompression Profiles” (Nishi & Kuehn). The original source was available only as scanned images inside a PDF; the goal of this project is to recover a compilable and runnable version of the 1973 Fortran code.

All example dives in dives/ reproduce the reference output from the report.

What’s here

src/main.f — Fortran source files transcribed from the 1973 document.
dives/ — Input files (and corresponding expected outputs extracted from the report) for several example dives.

For full technical documentation of the model, see the Technical Reference.

Run

The original programs read deck-style input describing the dive(s) and options. This port keeps the same spirit:

./run "Impulse Dive - 200ft 30m"

Contributing

Help is very welcome! Suggested ways to contribute:

Spot and fix transcription mistakes. If a sample differs, isolate the first divergence versus the expected listing in dives/ and inspect the adjacent code lines for common OCR/copying errors.
Improve portability. Test with multiple compilers/OSes and propose minimal fixes that don’t deviate from the original logic.
Add tests. Small scripts that run inputs and diff outputs against references are appreciated.

Please open a PR with:

A clear description of the change,
The smallest possible diff,
Before/after output snippets if you’re restoring a match to the report.

Safety disclaimer

This code is a historical and research reconstruction of a 1973 decompression model. It is not validated for real-world dive planning or life-support decisions. Do not use it to plan dives.