Diamond function: Difference between revisions

Wikispaces>genewardsmith
**Imported revision 243027989 - Original comment: **
Wikispaces>genewardsmith
**Imported revision 243257651 - Original comment: **
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<h2>IMPORTED REVISION FROM WIKISPACES</h2>
<h2>IMPORTED REVISION FROM WIKISPACES</h2>
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=Definition=
=Definition=
If S is a finite set of positive real numbers, then the diamond of S, Diamond(S), is the set {octave-reduce(u/v) | u,v in S}; that is, the set of all ratios of any two elements of S, reduced to the octave. The diamond of a set is usually considered in connection with just intonation, in which case S is a set of rational numbers. The important special case where S is the set of odd integers less than or equal to an odd n is called the tonality diamond, and is often taken as the set of theoretical consonances in the n odd limit. This can be justified on the grounds that these are just the intervals appearing in the "chord of nature", or overtone series, hence objecting to 17/16 on the grounds it isn't actually very consonant doesn't take account of the fact that the integers up to 17, a "chord of nature", contain this interval.  
Given a collection of notes S, the //diamond// of S, diamond(S), is the set of intervals between those notes, taking the intervals in direct and inverted form, reduced to an octave. For instance, given the notes {1, 3, 5}, diamond({1, 3, 5}) is {1, 6/5, 5/4, 4/3, 3/2, 8/5, 5/3}). The diamond of a set is usually considered in connection with just intonation, in which case S is a set of rational numbers, but it applies to any collection; for instance diamond({0, 400, 700}) where the notes are expressed in cents, is {0, 300, 400, 500, 700, 800, 900}. The important special case where S is the set of odd integers less than or equal to an odd n is called the tonality diamond, and is often taken as the set of theoretical consonances in the n odd limit. This can be justified on the grounds that these are just the intervals appearing in the "chord of nature", or overtone series, hence objecting to 17/16 on the grounds it isn't actually very consonant doesn't take account of the fact that the integers up to 17, a "chord of nature", contain this interval.  


=Creating scales=
=Creating scales=
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If S is a finite set of positive real numbers, then the diamond of S, Diamond(S), is the set {octave-reduce(u/v) | u,v in S}; that is, the set of all ratios of any two elements of S, reduced to the octave. The diamond of a set is usually considered in connection with just intonation, in which case S is a set of rational numbers. The important special case where S is the set of odd integers less than or equal to an odd n is called the tonality diamond, and is often taken as the set of theoretical consonances in the n odd limit. This can be justified on the grounds that these are just the intervals appearing in the &amp;quot;chord of nature&amp;quot;, or overtone series, hence objecting to 17/16 on the grounds it isn't actually very consonant doesn't take account of the fact that the integers up to 17, a &amp;quot;chord of nature&amp;quot;, contain this interval. &lt;br /&gt;
Given a collection of notes S, the &lt;em&gt;diamond&lt;/em&gt; of S, diamond(S), is the set of intervals between those notes, taking the intervals in direct and inverted form, reduced to an octave. For instance, given the notes {1, 3, 5}, diamond({1, 3, 5}) is {1, 6/5, 5/4, 4/3, 3/2, 8/5, 5/3}). The diamond of a set is usually considered in connection with just intonation, in which case S is a set of rational numbers, but it applies to any collection; for instance diamond({0, 400, 700}) where the notes are expressed in cents, is {0, 300, 400, 500, 700, 800, 900}. The important special case where S is the set of odd integers less than or equal to an odd n is called the tonality diamond, and is often taken as the set of theoretical consonances in the n odd limit. This can be justified on the grounds that these are just the intervals appearing in the &amp;quot;chord of nature&amp;quot;, or overtone series, hence objecting to 17/16 on the grounds it isn't actually very consonant doesn't take account of the fact that the integers up to 17, a &amp;quot;chord of nature&amp;quot;, contain this interval. &lt;br /&gt;
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