Tenney–Euclidean temperament measures: Difference between revisions
The wedgies should be weighted too |
Interpretation of Graham's RMS |
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$$ \norm{M_W}_2 = \sqrt {\abs{V_W V_W^\mathsf{T}}} $$ | $$ \norm{M_W}_2 = \sqrt {\abs{V_W V_W^\mathsf{T}}} $$ | ||
where {{!}} | where {{!}}·{{!}} denotes the determinant, and {{t}} denotes the transpose. | ||
Graham Breed and [[Gene Ward Smith]] have proposed different RMS norms. Let us denote the RMS norm of ''M'' as ‖''M''‖<sub>RMS</sub>. In Graham's paper<ref name="primerr">[http://x31eq.com/temper/primerr.pdf ''Prime Based Error and Complexity Measures''], often referred to as ''primerr.pdf''</ref>, an RMS norm is proposed as | |||
$$ \norm{M_W}_\text{RMS} = \sqrt {\abs{\frac {V_W V_W^\mathsf{T}}{n}}} = \frac {\norm{ | $$ \norm{M_W}_\text{RMS} = \sqrt {\abs{\frac {V_W V_W^\mathsf{T}}{n}}} = \frac {\norm{M_W}_2}{\sqrt {n^r}} $$ | ||
where ''n'' is the number of primes up to the prime limit ''p'', and ''r'' is the rank of the temperament, which equals the number of | where ''n'' is the number of primes up to the prime limit ''p'', and ''r'' is the rank of the temperament. Thus ''n''<sup>''r''</sup> is the number of permutations of ''n'' things taken ''r'' at a time with repetition, which equals the number of entries of the wedgie in its full tensor form. | ||
: '''Note''': that is the definition used by Graham Breed's temperament finder. | : '''Note''': that is the definition used by Graham Breed's temperament finder. | ||
Gene Ward Smith has defined another RMS norm, | |||
$$ \norm{M_W}_\text{RMS}' = \sqrt {\frac{\abs{V_W V_W^\mathsf{T}}}{C(n, r)}} = \frac {\norm{ | $$ \norm{M_W}_\text{RMS}' = \sqrt {\frac{\abs{V_W V_W^\mathsf{T}}}{C(n, r)}} = \frac {\norm{M_W}_2}{\sqrt {C(n, r)}} $$ | ||
where {{nowrap|C(''n'', ''r'')}} is the number of combinations of ''n'' things taken ''r'' at a time, which equals the number of entries of the wedgie. | where {{nowrap|C(''n'', ''r'')}} is the number of combinations of ''n'' things taken ''r'' at a time without repetition, which equals the number of entries of the wedgie in the usual, compressed form. | ||
: '''Note''': that is the definition currently used throughout the wiki, unless stated otherwise. | : '''Note''': that is the definition currently used throughout the wiki, unless stated otherwise. |