event_probability

std.stats.event_probability · Level L0

The probability of an event E on a finite sample space with masses p: the sum of the masses of the outcomes in E, given as a 0/1 indicator. Only when the outcomes are equally likely is it |E|/|S|.

P(E) = Σ_{s∈E} p(s)

Signature

event_probability(p: f64[k], E: f64[k]) → f64[]

Structure

The function as NOVA stores it: one box per input, operation and output, and arrows that carry values. A double border marks another library function this one runs — called once, or by Scan once per element; select it to open that function.

input
operation
constant
call
output

Verification

Signature proven by NOVA’s shape solver, for every size.
Equal to the reference sum of p over the outcomes in E in exact rational arithmetic, on all 40 test cases.
All 40 float64 results are exact: the error is zero.
Interpreter and NumPy backend return bit-identical results.
At float32 too: the 40 test cases rounded to float32, and 40 of them exact, with zero error.

Accuracy in detail

correctly rounded (the float64 nearest the exact value): 100%
bit-equal to the NumPy formula in float64: 100%
largest error, in units in the last place: 0

Identity

Calls

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Called by

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sha256:1940ef4d90617882989879d1b167a2b6650121194fc883a447452a7aeb11aa98

The semantic hash of the graph. It changes when the program changes, and never when only its documentation does.

Control handle

Symbol: Ω:std.stats.event_probability · Ω:event_probability
Pins: sha256:59c62cc5aea52b4ad526bd4b94e8f4036ee8a24e3616586e0a9dabf94c976f6fthis graph and the 1 it reaches through calls
Evidence: sha256:18b6caaedfc6fcaad3b5d7e4ec6794919656b726b738b60a2892b3688b89b722the hash of its verification record
Needs: no capability: a pure function

Through NOVA’s control layer, the symbol launches this function only while the program still matches what it pins: a change to this graph, or to any graph it reaches, needs a migration first.