Harmonic entropy: Difference between revisions

Mike Battaglia (talk | contribs)
Mike Battaglia (talk | contribs)
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However, in practice, the "unnormalized entropy" appears to be an extremely good approximation to the normalized entropy for large values of <math>N</math>. The resulting curve has the same minima and maxima as HE, the same general shape, and for all intents and purposes looks exactly like HE, just shifted on the y-axis.
However, in practice, the "unnormalized entropy" appears to be an extremely good approximation to the normalized entropy for large values of <math>N</math>. The resulting curve has the same minima and maxima as HE, the same general shape, and for all intents and purposes looks exactly like HE, just shifted on the y-axis.


It would be nice to show that the unnormalized entropy converges to the normalized entropy, up to a constant additive shift or multiplicative scaling, in the limit of large <math>N</math>. However, we will leave this for future research, as well as the question of how to do an exact derivation of the normalized entropy function.
Here are some examples for different values of <math>s</math>. All of these are Shannon HE (<math>a=1</math>), using <math>\sqrt{nd}</math> weights, with unreduced rationals (more on this below), with the bound that <math>nd < 1000000</math>, just with different values of <math>s</math>. All have been scaled so that the minimum entropy is 0, and the maximum entropy is 1:
 
[[File:HE vs UHE s=0.5%.png]]
 
[[File:HE vs UHE s=1%.png]]
 
[[File:HE vs UHE s=1.5%.png]]
 
As you can see, the unnormalized version is extremely close to a linear function of the normalized one. A similar situation holds for larger values of <math>a</math>. The Pearson correlation coefficient of "rho" is also given, and is typically very close to 1 - for example, for <math>s=1%</math>, it's equal to 0.99922. The correlation also seems to get better with increasing values of <math>N</math>, such that the correlation for N=1,000,000 (shown above) is much better than the one for N=10,000 (not pictured).
 
In the above examples, note that there are slightly adjusted values of <math>s</math> (usually by less than a cent) between the normalized and unnormalized comparisons for each plot. For example, in the plot for <math>s=1%</math>, corresponding to 17.2264 cents, we compare to a slightly adjusted UHE of 16.4764 cents. This is because, empirically, sometimes a very slight adjustment corresponds to a better correlation coefficient, suggesting that the UHE may be equivalent to the HE with a miniscule adjustment in the value of <math>s</math>.
 
It would be nice to show the exact relationship of unnormalized entropy to the normalized entropy in the limit of large <math>N</math>, and whether the two converge to be exactly equal (perhaps given some miniscule adjustment in <math>s</math> or <math>a</math>). However, we will leave this for future research, as well as the question of how to do an exact derivation of normalized HE.


For now, we will start with a derivation of the unnormalized entropy for <math>N=\infty</math>, as an interesting function worthy of study in its own right - not only because it looks exactly like HE, but because it leads to an expression for unnormalized HE in terms of the [[The_Riemann_Zeta_Function_and_Tuning|Riemann Zeta function]].
For now, we will start with a derivation of the unnormalized entropy for <math>N=\infty</math>, as an interesting function worthy of study in its own right - not only because it looks exactly like HE, but because it leads to an expression for unnormalized HE in terms of the [[The_Riemann_Zeta_Function_and_Tuning|Riemann Zeta function]].