Constrained tuning: Difference between revisions

More clarifications; adopt "just tuning map"
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All constrained tunings are standard temperament optimization problems. Specifically, as [[TE tuning]] can be viewed as a [[Wikipedia: Least squares|least squares problem]], CTE tuning can be viewed as an equality-constrained least squares problem.  
All constrained tunings are standard temperament optimization problems. Specifically, as [[TE tuning]] can be viewed as a [[Wikipedia: Least squares|least squares problem]], CTE tuning can be viewed as an equality-constrained least squares problem.  


The most common subject of constraint is the octave, which is assumed unless specified otherwise. For higher-rank temperaments, it may make sense to add multiple constraints, such as a pure-2.3 constrained tuning. For a rank-''r'' temperament, specifying ''m'' eigenmonzos will yield ''r'' - ''m'' [[Wikipedia: Degrees of freedom|degrees of freedom]] to be optimized.  
The most common subject of constraint is the octave, which is assumed unless specified otherwise. For higher-rank temperaments, it may make sense to add multiple constraints, such as a pure-2.3 (pure-octave pure-fifth) constrained tuning. For a rank-''r'' temperament, specifying a rank-''m'' constraint list will yield ''r'' - ''m'' [[Wikipedia: Degrees of freedom|degrees of freedom]] to be optimized.  


== Definition ==
== Definition ==
Given a temperament [[mapping]] V and the [[JIP]] J, we specify a weight and a skew, represented by transformation matrices W and X, respectively, and a ''p''-norm. Suppose the tuning is constrained by the eigenmonzo list M<sub>C</sub>. The goal is to find the generator list G by
Given a temperament [[mapping]] V and the [[just tuning map]] J, we specify a weight and a skew, represented by transformation matrices W and X, respectively, and a ''p''-norm. Suppose the tuning is constrained by the eigenmonzo list M<sub>C</sub>. The goal is to find the generator list G by


Minimize
Minimize
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The problem is feasible if
The problem is feasible if
# rank (M<sub>C</sub>) ≤ rank (V), and
# rank (M<sub>C</sub>) ≤ rank (V), and
# The subspaces of M<sub>C</sub> and N (V) are [[Wikipedia:linear independence|linearly independent]].
# The subgroups of M<sub>C</sub> and N (V) are [[Wikipedia:linear independence|linearly independent]].


== Computation ==
== Computation ==
As a standard optimization problem, numerous algorithms exist to solve it, such as [[Wikipedia: Sequential quadratic programming|sequential quadratic programming]], to name one. [[Flora Canou]]'s [https://github.com/FloraCanou/temperament_evaluator/blob/32a2198f1ebd9038fc64e02b10b547e011d4eaa4/te_optimizer_legacy.py tuning optimizer] is such an implementation in [https://www.python.org Python]. Note: it depends on [https://scipy.org/ Scipy].  
As a standard optimization problem, numerous algorithms exist to solve it, such as [[Wikipedia: Sequential quadratic programming|sequential quadratic programming]], to name one. [[Flora Canou]]'s [https://github.com/FloraCanou/temperament_evaluator/blob/32a2198f1ebd9038fc64e02b10b547e011d4eaa4/te_optimizer_legacy.py tuning optimizer] is such an implementation in [https://www.python.org Python]. Note: it uses [https://scipy.org/ Scipy].  


{{Databox| Code |
{{Databox| Code |
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<math>\langle \begin{matrix} 1200.000 & 1896.656 & 2786.625 & 3366.562 \end{matrix} ]</math>
<math>\langle \begin{matrix} 1200.000 & 1896.656 & 2786.625 & 3366.562 \end{matrix} ]</math>


The CTE tuning map is even sharper, with 3 tuned flat and 5 and 7 sharp.
The CTE tuning map is even sharper, with 3 tuned flat and 5 and 7 sharp:


<math>\langle \begin{matrix} 1200.000 & 1896.952 & 2787.809 & 3369.521 \end{matrix} ]</math>
<math>\langle \begin{matrix} 1200.000 & 1896.952 & 2787.809 & 3369.521 \end{matrix} ]</math>
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== Systematic name ==
== Systematic name ==
In D&D's guide to RTT, the [[Dave Keenan & Douglas Blumeyer's guide to RTT: alternative complexities #Naming|systematic name]] for the CTE tuning scheme is ''[[Dave Keenan %26 Douglas Blumeyer%27s guide to RTT: all-interval tuning schemes #Held-octave minimax-.28E.29S|held-octave minimax-ES]]'', and the systematic name for the CTWE tuning scheme is ''[[Dave Keenan %26 Douglas Blumeyer%27s guide to RTT: tuning fundamentals #Held-intervals|held-octave]] [[Dave_Keenan %26 Douglas Blumeyer%27s guide to RTT: alternative complexities #Tunings used in 7|minimax-E-lils-S]]''.
In D&D's guide to RTT, the [[Dave Keenan & Douglas Blumeyer's guide to RTT: alternative complexities #Naming|systematic name]] for the CTE tuning scheme is ''[[Dave Keenan %26 Douglas Blumeyer%27s guide to RTT: all-interval tuning schemes #Held-octave minimax-.28E.29S|held-octave minimax-ES]]'', and the systematic name for the CTWE tuning scheme is ''[[Dave Keenan %26 Douglas Blumeyer%27s guide to RTT: tuning fundamentals #Held-intervals|held-octave]] [[Dave Keenan %26 Douglas Blumeyer%27s guide to RTT: alternative complexities #Tunings used in 7|minimax-E-lils-S]]''.


[[Category:Terms]]
[[Category:Terms]]
[[Category:Math]]
[[Category:Math]]
[[Category:Regular temperament tuning]]
[[Category:Regular temperament tuning]]