Re^2: A better way of lookup?

$lookup = exp( -2.276 + 0.997 * log( $v ) );

That's a pretty good fit(*) -- a lot closer than I got -- but, this is intended to replace the Mysterious Function, and on balance, I think those constants make it even more mysterious.

I'm not particularly happy with my mysterious lookup table either, but every other attempt I've had screws up the results to a greater or lesser extent, whereas this works. I just need to come up with some documentation to explain it. (Not easy!).

(* However, I would be very interested to know how you derived that equation?)

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'

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Re^3: A better way of lookup? by hdb (Monsignor) on Apr 26, 2015 at 13:43 UTC
Paste the data into Excel as two columns, apply LN to the data, use SLOPE and INTERCEPT to get the constants. That gives you have a linear formula to predict the log of the desired value as a funtion of the log of the input, therefore take EXP on the result. If you want to do it in Perl, have a look at this: Re^5: Data range detection?. There is a coefficients function in that module. Update: On documentation, I remember that all these numbers are milliseconds, so translating into seconds, minutes, hours, days, and years should be helpful.	[reply]

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Re^3: A better way of lookup?
by hdb (Monsignor) on Apr 26, 2015 at 13:43 UTC

Paste the data into Excel as two columns, apply LN to the data, use SLOPE and INTERCEPT to get the constants. That gives you have a linear formula to predict the log of the desired value as a funtion of the log of the input, therefore take EXP on the result. If you want to do it in Perl, have a look at this: Re^5: Data range detection?. There is a coefficients function in that module.

Update: On documentation, I remember that all these numbers are milliseconds, so translating into seconds, minutes, hours, days, and years should be helpful.

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