# interval.density

Get the intervals analysis of a collection of notes

Returns an array with the format `[p, m, n, s, d, t]` where:

-   p: the number of perfect fourths or fifths
-   m: the number of major thirds or minor sixths
-   n: the number of major sixths or minor thirds
-   s: the number of major seconds or minor sevenths
-   d: the number of major sevents or minor seconds
-   t: the number of tritones

This is, mostly, an academic puzzle to show the expresiveness of tonal.
Implements the ideas found in "The Analysis of Intervals" chapter from
[Harmonic Materials of Modern Music](<>):

> The letters _pmn_, therefore, represent intervals commonly considered
> consonant, whereas the letters _sdt_ represent the intervals commonly
> considered dissonant. (...) A sonority represented, for example, by the
> symbol `sd^2`, indicating a triad composed of one major second and two minor
> seconds, would be recognized as a highly dissonant sound, while the symbol
> `pmn` would indicate a consonant sound.

**Parameters**

-   `notes` **([Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)\|[String](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String))** the notes to analyze

Returns **[Array](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array)** the _pmnsdt_ array