Iss. 14 · Spring 2026 · A nocturnal journal

AI for simulation, set down with the patience of a coastal observer at the blue hour.

Plate I · A diagram of simulation primitives, after Halley

FEATURE · CHAPTER ONE

A patient note on simulation

Simulation is, at its quietest, the discipline of asking a model to keep telling us the truth long after the experiment has been packed away. simulai.net is the working journal of that practice — a place where calibration drift, observation noise, and the slow turning of integration steps are treated with the dignity of long sentences.

We publish three things, and only three. The first is a field log: short, dated entries from operators of simulators in fluid dynamics, ecology, and policy. The second is the parameter table — a record of which constants have been changed, by whom, and at what cost. The third is the night chart: a quiet visualisation of where each simulator stands at the hour of going to print.

PARAMETER TABLE · CHAPTER TWO

A table of working numbers

Six instruments, six measurements, observed nightly. Numbers count up when this page first comes into view.

simulators online

0

across 4 instruments

mean step latency

0ms

last 24 hours, p50

runs published

0

since 2019, cumulative

calibration drift

0

RMS, normalised

field logs filed

0

all volumes

tide of correctness

0%

end-to-end test, last build

COMPARISON · CHAPTER THREE

Two ways of measuring a tide

Continuous solvers

Smoothness is bought with patience. We treat a Runge-Kutta walk as a slow letter, written one well-considered sentence at a time. The report is integrative: the tide is the area under the curve, not the curve itself.

  • · adaptive step size, error-controlled
  • · energy-preserving when asked
  • · ideal for fluids and fields

Discrete simulators

Events are counted, never approximated. The simulator is a quiet ledger of arrivals and departures. Determinism is the price of clarity, and we pay it gladly: every run can be replayed, sentence for sentence.

  • · deterministic replay
  • · sub-millisecond scheduling
  • · ideal for queues and ecologies

FIELD LOG · CHAPTER FOUR

An entry from the night desk

03:14, the second Wednesday in April. The fluid simulator on rig B-2 reported a thirty-second drift in the direction of warmer, slower currents. We adjusted the prior on the inflow temperature by half a kelvin and the residuals fell into line, like a row of small boats settling at moor.

The discrete ledger on rig D-4, by contrast, was untroubled. It counted seventeen thousand events between dusk and dawn. Three of them deserved attention. One asked, politely, whether the queue was being read in the correct order. We are still considering the question.

— M. Lenoir, watch officer, simulai.net

COLOPHON

Set in DM Sans, Libre Baskerville, & Space Mono

simulai.net is composed at the night desk and committed at first light. It uses geometric headlines for clarity, a warm serif for the body, and a monospace for numbers. The page is built to be read aloud and to be looked at in silence.

simulai · .net · published quarterly · depth: 14 fathoms