Hobbit: Difference between revisions
Wikispaces>genewardsmith **Imported revision 187427749 - Original comment: ** |
Wikispaces>genewardsmith **Imported revision 193568886 - Original comment: ** |
||
Line 1: | Line 1: | ||
<h2>IMPORTED REVISION FROM WIKISPACES</h2> | <h2>IMPORTED REVISION FROM WIKISPACES</h2> | ||
This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | This is an imported revision from Wikispaces. The revision metadata is included below for reference:<br> | ||
: This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt> | : This revision was by author [[User:genewardsmith|genewardsmith]] and made on <tt>2011-01-15 23:23:45 UTC</tt>.<br> | ||
: The original revision id was <tt> | : The original revision id was <tt>193568886</tt>.<br> | ||
: The revision comment was: <tt></tt><br> | : The revision comment was: <tt></tt><br> | ||
The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | The revision contents are below, presented both in the original Wikispaces Wikitext format, and in HTML exactly as Wikispaces rendered it.<br> | ||
Line 13: | Line 13: | ||
Denoting the OE seminorm for any element x of interval space by T(x), we first define the hobbit of an odd-numbered scale; that is, a scale for which v[1] is an odd number. If v[1] is odd then for each integer j, 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that <v|m> = j, 0 less than <J|m> less than or equal to 1 where J is the JI mapping <log2(2) log2(3) ... log2(p)|, and T(m) is minimal. | Denoting the OE seminorm for any element x of interval space by T(x), we first define the hobbit of an odd-numbered scale; that is, a scale for which v[1] is an odd number. If v[1] is odd then for each integer j, 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that <v|m> = j, 0 less than <J|m> less than or equal to 1 where J is the JI mapping <log2(2) log2(3) ... log2(p)|, and T(m) is minimal. | ||
If v[1] is even, we choose a monzo u such that T(u) is minimal under the condition that T(u) > 0; in other words, u is a shortest positive length interval. Then for each integer j, where 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that <v|m> = j, 0 less than <J|m> less than or equal to 1, and where T(2m - u) is minimal. | If v[1] is even, we choose a monzo u such that T(u) is minimal under the condition that T(u) > 0; in other words, u is a shortest positive length interval. Then for each integer j, where 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that <v|m> = j, 0 less than <J|m> less than or equal to 1, and where T(2m - u) is minimal. It should be noted that while this gives a canonical choice, the inverse hobbit is full equal as a scale to the cannonical hobbit. | ||
The intervals selected by this process are a [[transversal]] of | The intervals selected by this process are a [[transversal]] of the scale, and we may now apply the chosen tuning to the monzos in the transversal, obtaining values (in cents or fractional monzos) defining a scale. The monzos in the transversal are defined only modulo the commas of the temperament, but since these are tempered out this does not affect the definition of the scale. | ||
An alternative and equivalent approach is to work directly with the notes of the temperament, using the [[Tenney-Euclidean metrics|temperamental norm]] defined on the note classes of the temperament modulo period (an octave or fraction of an octave) of the temperament. | An alternative and equivalent approach is to work directly with the notes of the temperament, using the [[Tenney-Euclidean metrics|temperamental norm]] defined on the note classes of the temperament modulo period (an octave or fraction of an octave) of the temperament. | ||
Line 32: | Line 32: | ||
Denoting the OE seminorm for any element x of interval space by T(x), we first define the hobbit of an odd-numbered scale; that is, a scale for which v[1] is an odd number. If v[1] is odd then for each integer j, 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that &lt;v|m&gt; = j, 0 less than &lt;J|m&gt; less than or equal to 1 where J is the JI mapping &lt;log2(2) log2(3) ... log2(p)|, and T(m) is minimal.<br /> | Denoting the OE seminorm for any element x of interval space by T(x), we first define the hobbit of an odd-numbered scale; that is, a scale for which v[1] is an odd number. If v[1] is odd then for each integer j, 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that &lt;v|m&gt; = j, 0 less than &lt;J|m&gt; less than or equal to 1 where J is the JI mapping &lt;log2(2) log2(3) ... log2(p)|, and T(m) is minimal.<br /> | ||
<br /> | <br /> | ||
If v[1] is even, we choose a monzo u such that T(u) is minimal under the condition that T(u) &gt; 0; in other words, u is a shortest positive length interval. Then for each integer j, where 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that &lt;v|m&gt; = j, 0 less than &lt;J|m&gt; less than or equal to 1, and where T(2m - u) is minimal.<br /> | If v[1] is even, we choose a monzo u such that T(u) is minimal under the condition that T(u) &gt; 0; in other words, u is a shortest positive length interval. Then for each integer j, where 0 less than j less than or equal to v[1], we choose a corresponding monzo m such that &lt;v|m&gt; = j, 0 less than &lt;J|m&gt; less than or equal to 1, and where T(2m - u) is minimal. It should be noted that while this gives a canonical choice, the inverse hobbit is full equal as a scale to the cannonical hobbit.<br /> | ||
<br /> | <br /> | ||
The intervals selected by this process are a <a class="wiki_link" href="/transversal">transversal</a> of | The intervals selected by this process are a <a class="wiki_link" href="/transversal">transversal</a> of the scale, and we may now apply the chosen tuning to the monzos in the transversal, obtaining values (in cents or fractional monzos) defining a scale. The monzos in the transversal are defined only modulo the commas of the temperament, but since these are tempered out this does not affect the definition of the scale.<br /> | ||
<br /> | <br /> | ||
An alternative and equivalent approach is to work directly with the notes of the temperament, using the <a class="wiki_link" href="/Tenney-Euclidean%20metrics">temperamental norm</a> defined on the note classes of the temperament modulo period (an octave or fraction of an octave) of the temperament.<br /> | An alternative and equivalent approach is to work directly with the notes of the temperament, using the <a class="wiki_link" href="/Tenney-Euclidean%20metrics">temperamental norm</a> defined on the note classes of the temperament modulo period (an octave or fraction of an octave) of the temperament.<br /> |