Momentum phase

Momentum phase from 0 (retracement) to 3 (explosion); on this chart's wiring it reads 2 on every bar.

Each bar gets a phase label from five inputs: two rate-of-change readings (roc_fast, roc_slow), a volume momentum (obv_momentum), the close and an EMA (ema_fast). It labels a bar 3 when both rate-of-change readings are strong, volume momentum is positive and the close is above the EMA; 2 when both are modestly positive with positive volume momentum; 0 when either is negative; and 1 otherwise. The output is the highest label over the last three bars.

How to read it

The line sits in its own pane below the price and is meant to take whole values from 0 to 3.
On this chart it is a flat line at 2 across all 20,160 sampled SPY bars, so it says nothing about the price.
The cause is the wiring: all five inputs get the close price, so the rate-of-change and volume inputs are price levels, and the EMA equals the close, which keeps explosion (3) from ever firing.
A real reading needs a strategy that feeds rate-of-change, OBV momentum and EMA indicators into these inputs; this chart does not.

What it outputs

Momentum phase: Phase 0 retracement, 1 consolidation, 2 acceleration, 3 explosion: the highest label over the last three bars. Flat at 2 on this chart.

Pitfalls

Broken on this chart: the flat 2 comes from the input wiring, not from the market, so it carries no momentum information here.
The output holds the highest label of the last three bars, so an explosion (3) stays visible two bars longer and a retracement (0) is hidden for up to two bars after a 2 or 3.
On a bar where an input is missing it returns 1 (consolidation) and skips the history, so a data gap reads as calm rather than blank.