/**
 * Anomaly injection — `anomaly="p"` on a numeric `<gen>`.
 *
 * With probability `p` a value is turned into an OUTLIER: multiplied by
 * `anomaly_factor` (default 10), so it lands far outside the normal range. One
 * PRNG draw per row → deterministic and seekable, both engines (same wrapper as
 * `missing`). Useful for stress-testing pipelines and detectors against spikes.
 *
 * v1 injects the outliers; a ground-truth label column (which rows are
 * anomalous) is the next iteration — it needs sequence-level plumbing so a
 * companion `_anomaly` flag stays consistent across both engines.
 */
export interface AnomalySpec {
    /** Probability in [0, 1] a value becomes an outlier. */
    readonly p: number;
    /** Multiplier applied to a value that is selected as an outlier. */
    readonly factor: number;
}
/** Parse `anomaly` / `anomaly_factor`; `undefined` when no `anomaly` is set. Throws on bad input. */
export declare function parseAnomaly(attrs: Record<string, string | undefined>): AnomalySpec | undefined;
/**
 * Turn each selected value into an outlier (× `factor`), one PRNG draw per row.
 * Non-numeric values are left untouched (outliers only make sense for numbers).
 * Mutates and returns `values`.
 *
 * `flagsOut`, when given, records what ACTUALLY HAPPENED to the row, so an
 * `anomaly_flag` column is ground truth rather than a record of intent.
 *
 * It used to record the SELECTION (`draw < p`) on the reasoning that anomaly is a
 * numeric-only feature, so selected == spiked. That holds only for the gens whose
 * output is numeric by construction. A `type="template"` column of surnames is
 * selected like any other and then left alone here — and came out flagged `true`
 * beside an untouched ordinary name, while the page promised the flag and the
 * spike "can never disagree". A label that marks a row nothing happened to is
 * worse than no label: it is training data for an anomaly detector, and every
 * such row teaches it something false.
 *
 * `draw` is asked for the uniform of row i rather than for "the next" one: the
 * streaming engine derives it from the row, and the in-memory engine passes a
 * closure over its own PRNG. Same rows selected either way.
 */
export declare function applyAnomaly(values: string[], spec: AnomalySpec, draw: (i: number) => number, flagsOut?: boolean[]): string[];
/**
 * The spike keeps the SHAPE of the value it replaced.
 *
 * Multiplying and re-stringifying threw away everything the column had already
 * been rendered with — the zero padding `length=` asked for, and the decimal
 * places `decimals=` asked for — so the outlier rows were the only ones in the
 * file with a different shape:
 *
 *     length="5"    00014 00046 00053 …  and then  117
 *     decimals="2"  85.66 40.97 11.52 …  and then  6.445
 *
 * That is worse than it looks. A column of fixed-width identifiers stops being
 * fixed width on exactly the rows a test is about to exercise, and a column
 * declared with `decimals` is typed a float in Parquet — a spike with a third
 * place is a value the declared type never promised. An outlier is meant to be
 * far from the others in VALUE, not in format.
 *
 * So: the same number of decimal places, and at least the same digit width. The
 * padding only ever adds, so a spike that genuinely outgrew the width keeps its
 * extra digits — which is the whole point of one.
 */
export declare function keepShape(original: string, spiked: number): string;
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