rhythm-math

rhythm-math

Rhythm mathematics for the browser and web audio — tempo, polyrhythm, groove, syncopation, and meter.

Install

npm install rhythm-math

API

Types

• Tempo — { bpm: number }
• Polyrhythm — { rates: number[] }
• Groove — { velocities: number[], offsets: number[] }
• Meter — { numerator: number, denominator: number }

Tempo

• bpmToMs(bpm) → milliseconds per beat
• msToBpm(ms) → BPM
• tempoCurve(start, end, steps, curve) → number[] where curve is "linear", "exponential", or "logarithmic"

Polyrhythm

• polyrhythmCycleLength(rates) → LCM of rates
• polyrhythmPattern(rates) → binary arrays per voice
• polyrhythmDensity(rates) → average hit density

Groove

• swingFactor(grid, amount) → swung grid positions
• grooveVelocity(pattern, accents?) → MIDI velocities (0–127)
• microtiming(offsets, humanize) → humanized offsets

Syncopation

• syncopationScore(pattern, meterNumerator) → Longuet-Higgins/Lee score
• offbeatDensity(pattern, meterNumerator) → fraction of off-beat hits
• rhythmicEntropy(pattern) → Shannon entropy of interval distribution

Meter

• isSimple(meter), isCompound(meter), isOdd(meter) → boolean
• beatCount(meter) → main beats per measure
• subdivision(meter) → subdivisions per beat
• downbeats(measures, meter) → downbeat positions
• timeSignatureChanges(meters, repeats?) → expanded meter sequence

License

MIT