D07-F08-A06 · LEVEL 2 GUIDED LAB · SYNTHETIC DATA

Log Price Transform

How does a positive price series become additive in proportional changes? Walk the evidence clock one stage at a time. This lab teaches the publication contract; it does not simulate returns, platform parity, or trade performance.

Selected expression

L_t=ln(P_t), P_t>0; log_return=L_t-L_(t-1)

Availability rule

An output at t may use only finite, basis-consistent observations available through t; chart alignment never moves the information clock backward.

calculated · step 1 of 7

Verified synthetic fixture

This lab is paired with datasets/implementation-fixtures.json: 96 deterministic, oldest-to-newest observations spanning oscillating, rising, and moderating regimes. It is teaching data—not market history or predictive evidence.

Canonical latest output (D07-F08-A06)
{
  "log_price": 4.605078326469135,
  "log_return": -0.0146799922919163
}

Executable checks cover this result, flat/zero-volume boundaries, invalid timestamps, and prefix causality in both language entry points.