Operations on MOSes: Difference between revisions

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Dualization: Rewrote dualization section
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== Dualization ==
== Dualization ==
'''Dualization''' creates new MOS patterns from a MOS pattern in a specific EDO by swapping step sizes with step frequencies.
Given a MOS pattern ''x''L ''y''s with concrete step sizes L and s, '''dualization''' is the process in which the values of ''x'' and L are swapped, the values of ''y'' and s are swapped, or both are swapped. This is not to be confused with the sister operation.
 
xL ys can be read as a formula: ''x'' * ''L'' + ''y'' * ''s'' = edo-size. From this formula it is clear we can swap for example ''x'' (the number of L-steps) with ''L'' (the size of the L-step) to get a new MOS scale in the same EDO, this is called the '''L-dual'''. Similarly we have the '''s-dual''' and when swapping both we get the '''Ls-dual''' (or just the '''dual''').
 
For example, take 5L 2s in 43 EDO, with L=7 and s=4:
* The L-dual is 7L 2s with L=5 and s=4
* The s-dual is 5L 4s with L=7 and s=2
* The Ls-dual is 7L 4s with L=5 and s=2


Depending on which values are swapped, a different MOS scale is produced; however, the relationship between these scales depends on the sizes of L and s, and since ''x * L + y * s'', these relationships also depends on the edo. Additionally, it's possible for a dual to be itself, if either ''x'' and L are the same or ''y'' and s are the same.
{| class="wikitable"
|+Example with 5L 2s in 43edo
!MOS
!Step pattern
!Notes about step sizes
!Step visualization
|-
|5L 2s
|LLLsLLs
|L = 7, s = 4
Original scale
|{{Step vis|7 7 7 4 7 7 4}}
|-
|7L 2s
|LLLLsLLLs
|L = 5, s = 4
L-dual, as ''x'' and L are swapped
|{{Step vis|5 5 5 5 4 5 5 5 4}}
|-
|5L 4s
|LLsLsLsLs
|L = 7, s = 2
s-dual, as ''y'' and s are swapped
|{{Step vis|7 7 2 7 2 7 2 7 2}}
|-
|7L 4s
|LLsLLsLLsLs
|L = 5, s = 2
Ls-dual, as ''x'' and L are swapped, as are ''y'' with s
|{{Step vis|5 5 2 5 5 2 5 5 2 5 2}}
|}
[[Category:MOS scale]]
[[Category:MOS scale]]