philox4x32_10

std.seq.philox4x32_10 · Level L5

Philox4x32-10: ten rounds of philox4x32_round (a Scan over r = 0 … 9) on four-word counters under a two-word key. Random123's generator: each output depends only on its counter and the key, so a tensor of counters draws all its numbers at once. Its authors report that it passes TestU01's BigCrush.

words = round₉ ∘ … ∘ round₀ (ctr)

Signature

philox4x32_10(ctr: i64[4, n], key: i64[2]) → i64[4, n]

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 Philox4x32-10 on Python ints, checked against Random123's known-answer vectors in exact rational arithmetic, on all 40 test cases.
All 612 int64 results are exact: the error is zero.
Interpreter and NumPy backend return bit-identical results.

Accuracy in detail

correctly rounded (the int64 nearest the exact value): 100%
bit-equal to the NumPy formula in int64: 100%
largest error, in units in the last place: 0

Note

The reference is a direct implementation on Python integers, where a·b is exact. That implementation reproduces Random123's three published known-answer vectors for Philox4x32-10, and so does this graph (see the stdlib tests).

Identity

Calls

philox4x32_round

Called by

philox_uniform

sha256:3ee978921421b9516476d9588f163ae31b82fda9a6e5dab636296778c44ebabe

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

Control handle

Symbol: Ω:std.seq.philox4x32_10 · Ω:philox4x32_10
Pins: sha256:e1a3dce7ecbdacaee824a7baf5d7a1fd7b5a2d7519cea9503649798239a448a6this graph and the 2 it reaches through calls
Evidence: sha256:e7b35d602ed171b5a3172aedd54588ba31cfc5bb15bf710e9021a8250534c7f3the 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.