Octave reduction: Difference between revisions

Separated general formulas from simple methods in two top-level sections
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=== Logarithmic measures ===
=== Logarithmic measures ===


For a starting interval <math>l</math> and octave <math>e</math> expressed in the same units, the reduced form <math>\text{red}(l, e)</math> of that interval can be found using this formula: <math>\text{red}(l, e) = r - e\left\lfloor{l/e}\right\rfloor</math>­.
For a starting interval <math>l</math> and octave <math>e</math> expressed in the same units, the reduced form <math>\text{red}(l, e)</math> of that interval can be found using this formula: <math>\text{red}(l, e) = r \bmod e</math>­, where <math>\bmod</math> is the modulo operation.


Example:
Example:


* Octave-reducing 412 steps of 97edo can be done by using the formula with <math>r = 412</math>, <math>e = 97</math>:<br><math>\begin{align}\text{red}(412, 97) &= 412 - 97\left\lfloor{412/97}\right\rfloor \\
* Octave-reducing 412 steps of 97edo can be done by using the formula with <math>r = 412</math>, <math>e = 97</math>:<br><math>\begin{align}\text{red}(412, 97) &= 412 \bmod 97 \\
&= 24\end{align}</math>
 
This formula can also be written without the modulo operation: <math>\text{red}(l, e) = r - e\left\lfloor{l/e}\right\rfloor</math>­.
 
Example:
 
* Octave-reducing 412 steps of 97edo again:<br><math>\begin{align}\text{red}(412, 97) &= 412 - 97\left\lfloor{412/97}\right\rfloor \\
&= 412 - 97\left\lfloor{4.24742\ldots}\right\rfloor \\
&= 412 - 97\left\lfloor{4.24742\ldots}\right\rfloor \\
&= 412 - 97 \cdot 4 \\
&= 412 - 97 \cdot 4 \\