discount_step

std.seq.discount_step · Level L0

One step of a discounted return: this reward plus γ times the return after it. The body that discounted_returns scans, backwards.

g′ = r + γ·g

Signature

discount_step(g: f64[], r: f64[], gamma: f64[]) → 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.

gf64[]gammaf64[]rf64[]MultiplylaterAddg2g2f64[]
  • input
  • operation
  • constant
  • call
  • output

Verification

  • Signature proven by NOVA’s shape solver, for every size.
  • Equal to the reference r + gamma * g in exact rational arithmetic, on all 40 test cases.
  • All 40 float64 results inside the running error bound; the closest uses 85% of it.
  • Interpreter and NumPy backend return bit-identical results.
Accuracy in detail
correctly rounded (the float64 nearest the exact value)
83%
bit-equal to the NumPy formula in float64
100%
largest error, in units in the last place
0.75

Identity

Calls
—
Called by
discounted_returns
sha256:9692746b555d3ec3cde0550d0e06ced838bb3261defec2b24c04efce5c02c598

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.discount_step · Ω:discount_step
Pins
sha256:9324f20c6b545ac48f745c6c7ef2a1f2b8d8f5d10d1590d9ae84d3c5b9cc96edthis graph alone
Evidence
sha256:98ebed674013a94a4ade70933f8e44b5fdcfaae6b7d702afa9762fd1e6a072c0the 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.