question on fixing the mpz_sizeinbase() command to work correctly

[American Citizen]

To everyone:

I still believe that adding just a few simple lines of C code will fix 
the mpz_sizeinbase() command to give the correct answer.

I am examining thousands of different numbers, maybe more.

Randall

On 3/17/24 11:46, marco.bodrato at tutanota.com wrote:
> Ciao Randall,
>
> 16 mar 2024, 23:50 da website.reader at protonmail.com:
>
>> I was sorting numbers based upon the count of digits that each had.
>>
> How many numbers? Lots of them?
>
>
>> However things didn't work right and I had to fix my code which used the gmp v6.3 mpz_sizeinbase() command.
>>
> Great, after reading the manual, and the definition of the function, you was able to correctly use its result. That's fine!
>
>
>> Here's the suggested fix for this command in a C++ code unit
>>
>> ==== start code.cpp unit here below this line ====
>>
> [just a handful of lines of simple code]
>
>
>> Can this simple fix be placed into gmp?
>>
> Your short code shows why there is no need to change the library.
> The GMP function is very fast giving, as documented, an approximation of the actual number of digits needed to represent the given number with the given base.
> Moreover, it is easy for the user to write a few lines of code to adjust the possible error.
> Your code is a brilliant example.
>
> Since you seem to need to classify many numbers, are you sure that the best way is to compute every time, again and again, the ui_pow_ui? Maybe it's more efficient to compute it once and compare it with a bunch of numbers giving the same result with mpz_sizeinbase, isn't it? Instead of recomputing the power, for the next number of digit, it is more efficient to update it... 5000 digits, 5001 digits, 5002 digits... with a fast small multiplication.
> It would be impossible to implement such an optimization if it the ui_pow_ui was hardcoded in the library, for each call of the function. Should the library let optimizations became more difficult to achieve?
>
> Should that function in the library be changed? The answer is no.
>
> Ĝis,
> mb
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