Justin Visser
c3f65a4029
rng.go is a construction point, not an abstraction wall; components take *rand.Rand directly (idiomatic Go dependency injection) and only RunScenario creates streams, from config seeds. Decided 2026-06-10 over the alternatives (interface wall, folding newRand into scenario.go).
21 lines
996 B
Go
21 lines
996 B
Go
// Package engine implements the agent-based spread model: build a social
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// network, run an independent cascade over it, and measure the effect of
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// education strategies. It is pure: no I/O, no web dependencies, and all
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// randomness flows from seeds in the config, so identical inputs always
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// produce identical runs.
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package engine
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import "math/rand/v2"
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// newRand returns a deterministic random stream for the given seed. The
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// engine never touches global random state; every source of randomness
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// (graph build, edge thresholds, education sampling) gets its own seeded
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// stream so each can be varied independently.
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//
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// This file is deliberately NOT a wall around math/rand/v2: components
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// take *rand.Rand parameters directly, the idiomatic Go shape. What is
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// centralised here is construction; RunScenario is the only caller, so
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// "all randomness flows from config seeds" is enforced by structure.
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func newRand(seed uint64) *rand.Rand {
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return rand.New(rand.NewPCG(seed, 0))
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}
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