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23h
awarded  Self-Learner
2d
revised Is there a fast divisibility check for a fixed divisor?
added 3 characters in body
Apr
25
revised Is there a fast divisibility check for a fixed divisor?
edited body
Apr
25
revised Is there a fast divisibility check for a fixed divisor?
added 6 characters in body; edited title
Apr
25
comment Is there a fast divisibility check for a fixed divisor?
@BillDubuque Done.
Apr
25
revised Is there a fast divisibility check for a fixed divisor?
added 480 characters in body
Apr
25
comment Is there a fast divisibility check for a fixed divisor?
@TravisJ Correct. That is what I meant with 'constant divisor' in the question.
Apr
25
comment Is there a fast divisibility check for a fixed divisor?
@TravisJ The code I listed is code to generate constants a and b. This is precomputation, and doesn't end up in the final code. The expressions all the way at the bottom of my answer is an example of the generated code for $76 \mid n$ for 64-bit integer $n$.
Apr
25
revised Is there a fast divisibility check for a fixed divisor?
added 2 characters in body
Apr
25
comment Is there a fast divisibility check for a fixed divisor?
@TravisJ Yes, integer division/modulo ranges from expensive to very expensive on CPUs. If I'm not mistaken two comparisons, one multiplication and one bitshift is faster than integer modulo on virtually every CPU in existence. This also extends to operations on very large integers.
Apr
25
revised Is there a fast divisibility check for a fixed divisor?
added 178 characters in body
Apr
25
asked Is there a fast divisibility check for a fixed divisor?
Apr
25
answered Is there a fast divisibility check for a fixed divisor?
Apr
17
asked Are there famous complex constants?
Apr
15
accepted How to continue this argument/proof?
Dec
15
awarded  Caucus
Oct
14
comment Prove that if all triangles have the same angle sum then the sum of the angles in any triangle must be 180.
Hint: find an example.
Jul
2
awarded  Curious
Oct
16
accepted Is this notation correct?
Oct
16
comment Is this notation correct?
@TobiasKildetoft I'm afraid that will hurt the understanding. This is for describing a cryptographic scheme, and placing $\text{large_expression}$ and $x$/$y$ further apart from eachother (by introducing another variable or function) will make it harder to see that some events are mutually exclusive, on which the security of the scheme relies.