QuanTAlib/lib/signals/predicates/isrising/IsRising.md

ISRISING: Rising Predicate

Pine Script's ta.rising asks a deceptively simple question — has this value beaten everything it's seen in the last n bars — and the "excludes the current bar" detail is the whole implementation.

Property	Value
Category	Signals (Predicates)
Inputs	Source (single series)
Parameters	n (lookback, must be >= 1)
Outputs	Single crisp series (IsRising)
Output range	{0.0, 1.0} while hot; NaN during warmup
Warmup	n + 1 bars
PineScript	ta.rising(source, n)

• ISRISING tests whether the current value is strictly greater than the maximum of the n bars preceding it.
• Similar: AtHighest, IsFalling | Trading note: The breakout-of-recent-range test; BecameTrue(IsRising(n)) on a source is the rising edge equivalent of a Breakout trigger.
• Part of the strategy-primitives signal algebra. The exact definition here — current > max(previous n), current bar excluded, comparison strict — was confirmed against the "most common understanding" during the design of this predicate, superseding an earlier draft that read Pine's ta.rising as adjacent-pair monotonicity.

Mathematical Foundation

\text{IsRising}_t(n) = \begin{cases} 1.0 & \text{if } x_t > \max(x_{t-1}, \ldots, x_{t-n}) \\ 0.0 & \text{otherwise} \end{cases}

The window is the previous n bars — the current bar is never compared against itself. A tie (x_t equal to the prior maximum) is 0.0: the comparison is strict. Contrast with AtHighest, whose window includes the current bar and asks a different question ("is the current bar the maximum"), which by definition is always at least a tie for the maximum, never a strict-greater-than test against itself.

Warmup

NaN until n confirmed prior bars exist — n + 1 total bars observed (the first bar can never have n predecessors).

Implementation Details

Confirm-Then-Push: Why No Rebuild Is Needed on Correction

The window (backed by a MonotonicDeque, same data structure as numerics/Highest) holds only confirmed prior bars, never the currently forming one. A tick with isNew = true first checks whether the previous forming bar's now-settled value should join the window (it does, if one exists), pushing it in with MonotonicDeque.PushMax — then only after that does the new tick become the new pending value. A tick with isNew = false (a correction) only ever overwrites the pending value; it never touches the window, since the window was never told about the currently-forming bar in the first place.

This is the same confirm-then-push pattern as ConfirmOnClose, applied to a rolling window instead of a single value, and it means IsRising needs no RebuildMax-on-correction logic at all — unlike AtHighest, whose inclusive window does need to rebuild, because a correction there changes a value that is already inside the window.

Performance Profile

Operation	Count	Notes
Deque push (amortized)	≤1	Only when a bar closes
Deque query	1	GetExtremum
Comparison	1	current > extremum
Total	O(1) amortized	Same complexity class as numerics/Highest

Validation

Test	Status
Warmup returns NaN for the first n bars	✅
n=1: strictly greater than the immediately preceding bar	✅
Tie returns false (strict comparison)	✅
Current bar is excluded from its own comparison	✅
Correction to the forming bar does not disturb the confirmed window	✅
NaN/Infinity substitution	✅
Batch/streaming parity	✅

Common Pitfalls

1. The current bar is never part of the comparison. IsRising(n) compares against the previous n bars only; a value tying its own immediately preceding value is not "rising," and a run of n identical values followed by a higher one is rising on that last bar, not sooner.
2. Do not confuse with AtHighest. IsRising(n) and AtHighest(n) ask genuinely different questions (exclusive vs. inclusive window) and use different MonotonicDeque correction strategies internally; they are not interchangeable even though both use "n" and a rolling maximum.
3. Warmup is n + 1, not n. The first bar can never have n predecessors, so the node needs to observe n+1 bars total before its first non-NaN output.

Usage Examples

// "Higher high than the last 5 confirmed bars"
var rising5 = new IsRising(5);

// Chained from another indicator
var trendAccelerating = new IsRising(new Roc(price, 10), 3);

References

• TradingView Pine Script Reference: ta.rising.