Accelerated Time¶

Learning objectives

After reading this chapter you will be able to:

Run the simulation's trading calendar faster than real time, and pick a speed for what you want to see
Say exactly what speeds up and what does not
Predict how a faster calendar changes the market you watch
Avoid the traps: restarts, dates in the statistics, auctions at high speed

One setting¶

./edumatcher.sh speed 24 && ./edumatcher.sh restart

EM_SPEED=N runs the trading calendar N times faster than the clock on the wall. At 24 a calendar day passes in an hour of wall time: the market opens, trades through the day, closes, sleeps through the night and opens again an hour later. Weekends and Swedish holidays pass too, at the same speed. EM_SPEED=1 (the default) is real time.

EM_START says where the faster calendar starts, as local time — the second argument:

./edumatcher.sh speed 24 2026-11-02T08:55 && ./edumatcher.sh restart

Without it the calendar starts at the real present moment. A start a few minutes before 09:00 on a weekday is the usual choice: the market opens almost at once.

By hand (without the container) the same two settings are the scheduler's --speed and --start flags, or the environment variables EDUMATCHER_SCHEDULER_SPEED and EDUMATCHER_SCHEDULER_START; see A Complete Set-up by Hand.

Choosing a speed¶

The trading day is 09:00–16:05: a 25-minute pre-open, a 5-minute opening auction, 6.5 hours of continuous trading, a 5-minute closing auction.

`EM_SPEED`	A trading day (09:00–16:05)	Continuous trading	An auction	A week	30 trading days	Good for
1	7 h 5 min	6 h 30 min	5 min	7 days	6 weeks	A live market alongside a course
10	42.5 min	39 min	30 s	16.8 h	4.2 days	A whole day inside one lesson
24	17.7 min	16.3 min	12.5 s	7 h	42 h	A day an hour; a week over a working day
60	7.1 min	6.5 min	5 s	2.8 h	17 h	Several days in a lesson; overnight runs
600	42.5 s	39 s	0.5 s	17 min	1.7 h	Soak tests: a month of closes in an afternoon

(Thirty trading days are six calendar weeks, weekends included.)

What speeds up, and what does not¶

Only the calendar is faster. Everything that happens during trading runs on the wall clock.

Faster (calendar time)	Not faster (wall clock)
The open, the auctions, the close, nights, weekends, holidays	How often each AI trader decides, how many orders a second the swarm sends
How far the true values move in a day: a compressed day moves as much as a real one	How long an order rests before its trader cancels it
How many headlines a trading day brings, and how soon a rumour resolves	The market maker's quoting rhythm
	Heartbeats, time-outs, every log and file timestamp

So a compressed day is a short day, not a fast day. At EM_SPEED=24 the traders send their usual orders a second, but continuous trading lasts 16 minutes, so a day has a twenty-fourth of the orders of a real one. Meanwhile the values move a whole day's worth in those 16 minutes. The consequences you can see:

Prices lag the value more. Value traders and the market maker have fewer orders to pull the price after a value that moves 24 times faster per minute. Measured with the s300-sim set-up: the typical gap between price and value (the RMS of ln(price / value)) was about 0.3 % at real speed, about 0.45 % at EM_SPEED=24 and about 3.5 % at 600.
News comes thick and fast. Six symbol headlines a trading day is one every three minutes of wall time at 24, one every 7 seconds at 600. Rumours that resolve after 8–60 trading minutes resolve after 20 s–2.5 min at 24.
Auctions get thin. A 5-minute auction lasts 12.5 s at 24 and half a second at 600 — barely time for the auction players to send their orders. Opening and closing prices at high speed come mostly from the market maker's quotes.
Order ages feel longer. A trader that cancels after 60 s keeps an order for a sixteenth of the continuous session at 24, and for longer than the whole session at 600.

For teaching, 10 to 60 keeps a market that looks right; above that, use it to test that the exchange keeps running, not to look at prices.

Traps¶

Every restart starts the calendar again. The accelerated clock begins at EM_START (or now) whenever the scheduler starts — after compose down/up, a reboot, or the container restarting a dead scheduler. With EM_START set, the market goes back to that morning. For a long accelerated run, set EM_START for the first start only, then remove it (from .env, or leave START= off make up-sim) and run the same up command again, so Compose recreates the container without it; the data stays. A container keeps the settings it was created with, so until then every restart still goes back to EM_START. Later restarts begin at the real present, which never goes back.

Dates are wall-clock dates. Statistics, clearing and the AI traders' daily results are filed by the date the wall clock shows, because every message is time-stamped with real time. At EM_SPEED=24 a whole compressed week lands on one real date: pm-stats-cli daily shows one row per symbol for that date, with the week's high and low; the AI swarm's daily summaries (ai_swarm/<date>-<worker>.jsonl, by UTC date) hold one line per trader per compressed day, numbered day 1, day 2, … in the file of the real date. If you need true daily statistics, run at real speed.

Load is per wall second. A faster calendar does not make the exchange work harder: the orders a second are the same. The disk grows by the same amount per wall-clock day at any speed (see Running It for Weeks), so a compressed month costs the disk of the real days it took to run.

A lesson plan at speed 10¶

Before class: start with EM_SPEED=10 and EM_START set to a weekday at 08:55, about five minutes before you want the open.
Pre-open and opening auction (3 minutes): watch the indicative prices form in book-gui; open the books at the open.
Continuous trading (39 minutes): inject a headline at minute 5 (News and Rumours), a rumour at minute 15, confirm or retract it at minute 20.
Closing auction (30 seconds) and close: compare the day's moves with the values (pm-market-sim --status --id OPS01 during trading).
After class: down, remove EM_START and EM_SPEED from .env, up -d — back to real hours.