Execution Modes (`bulk`, `harmonic`, `resolution`)

A locus can declare up to three named execution modes—bulk, harmonic, and resolution—to express distinct hardware execution strategies (vectorized batch throughput, cache-tiled per-class passes, and single-element scalar evaluation) over the same underlying locus state and arena.

locus Pricer {
    params { base_rate: Float = 0.05; }

    mode bulk(count: Int) -> Float {
        // Vectorized pass across a batch of inputs
        return self.base_rate * to_float(count);
    }

    mode harmonic(bucket: Int) -> Float {
        // Cache-tiled pass scoped to a specific class or partition
        return self.base_rate * to_float(bucket);
    }

    mode resolution(spot: Float) -> Float {
        // Latency-sensitive single scalar decision
        return spot * self.base_rate;
    }
}

The Three Execution Regimes

A locus declares only the modes it actually uses and invokes them with standard method call syntax (self.bulk(...), self.harmonic(...), self.resolution(...)):

Mode	Hardware Regime	Computation Shape	Typical Use Case
mode bulk(...)	High-throughput SIMD / vector units	Applies the same kernel across a large batch of elements in one pass.	Batch pricing, array transforms, columnar scans.
mode harmonic(...)	Cache-resident / locality-tiled	Processes elements grouped by class or partition so per-class state stays in L1/L2 cache.	Bucketed simulations, multi-instrument order books.
mode resolution(...)	Low-latency scalar pipeline	Evaluates a single input to produce an immediate single decision.	Per-request admission, single-order risk checks.

Note

In the current compiler release, mode declarations lower identically to synchronous fn members on the locus; the mode keyword documents the target hardware regime in the program graph without yet emitting distinct codegen passes. Because modes are substrate-facing surfaces, they cannot be declared fallible(E).

Shared State & Arena Semantics

All modes declared on a locus operate directly on the same params fields and locus arena:

• Zero state duplication: Switching between bulk warmup and per-event resolution requires no copying or synchronization between separate objects.
• Synchronous execution: Like ordinary locus methods, mode calls execute synchronously to completion, so two modes on the same locus instance never interleave concurrently over self.

When to Declare Modes

Most application and service loci only need lifecycle hooks (birth, run, dissolve) and standard fn methods. Reach for mode bulk, mode harmonic, and mode resolution only when a single stateful kernel genuinely executes in multiple hardware cost regimes over the same data.

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For the formal hypergraph specification underlying loci, projections, and modes, see The Design and the Language Reference.