/**
 * SLOPPINESS — the rarest lens: how many knobs do you REALLY have? Borrowed from "sloppy models" in systems
 * biology and physics (Sethna, Transtrum), an idea almost no optimizer ships. You think you're tuning five
 * variables; the response often cares about only two or three COMBINATIONS of them, and is nearly flat along
 * the rest. Those flat ("sloppy") directions are freedom: you can set them however is cheapest, fastest, or
 * safest without hurting the result. The steep ("stiff") directions are the ones you must hold precisely.
 *
 * SLOPPINESS fits the response curvature (the Hessian) around your data, eigen-decomposes it, and reads off
 * the spectrum: each eigenvector is a combination of your variables, each eigenvalue is how sharply the
 * result changes along it. A spectrum spanning orders of magnitude = a sloppy system: a few stiff
 * directions matter, the rest are free. The headline is the EFFECTIVE DIMENSIONALITY — "you have 5 knobs
 * but only 2 combinations truly move the needle."
 *
 * Honest by construction (DIAKRISIS): this is a LOCAL quadratic (Hessian) picture, valid where your data
 * concentrates; eigenvectors are reported as the literal variable loadings, stiffness as the eigenvalue
 * ratio to the stiffest. It abstains when there isn't enough data to fit a curvature.
 */
import { type Space } from "./space.js";
import { type Observation, type Goal } from "./engine.js";
export interface SloppyDirection {
    stiffness: number;
    kind: "stiff" | "sloppy";
    loadings: Array<{
        name: string;
        weight: number;
    }>;
}
export interface SloppinessReport {
    effectiveDims: number;
    totalDims: number;
    directions: SloppyDirection[];
    note: string;
}
/** Analyse how many independent combinations of variables actually matter (stiff) vs are free (sloppy). */
export declare function analyzeSloppiness(obs: ReadonlyArray<Observation>, space: Space, goal?: Goal): SloppinessReport;
export declare function sloppinessGauntlet(): {
    score: 0 | 100;
    checks: Array<{
        name: string;
        pass: boolean;
        detail: string;
    }>;
};
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