Questions tagged [modular-arithmetic]
99 questions
5
votes
1 answer
modulo with n instead of 0 without using if-statement
Is there a way to to express the following without using an if statement, but with mathematical operations instead?
{ 5 if x % 5 = 0, x % 5 otherwise }
maddingl
- 153
- 2
4
votes
3 answers
How to reverse in modular arithmetic
Given an RGB color {127, 255, 212} where scale is 0-255, VBA's RGB function find a long integer x such that
IntegerPart@{Mod[x,256],Mod[x/256,256],Mod[x/256^2,256]}
is equal to {127,255,212}. In this particular case the
x=13959039
How do i…
user13892
- 9,375
- 1
- 13
- 41
3
votes
2 answers
Evaluate modular fractions
If I have a list of numbers l = {256/11, 258/11, 263/11, 263/11, -22, -22, 251/11, 0, 261/11, -22, 265/11, 259/11, 0, 259/11} which I want to evaluate mod 26, how do I do that?
I know I can do Mod[l, 26], but that just gives me {256/11, 258/11,…
Matt G
- 349
- 2
- 9
2
votes
0 answers
Effective way of iterating multiplication modulo p
I am trying to compute discrete logarithms modulo p (in a naive way). I have three approaches
LogMod1[a_, b_, p_] := Block[{j = 0},
While[PowerMod[a, j, p] != b && j < p, j++];
j];
LogMod2[a_, b_, p_] := Block[{j = 0, aa = 1},
While[aa != b…
gerald
- 233
- 1
- 5
2
votes
1 answer
A Difficult Application of Modular Arithmetic
Looking to input a $p$ for the first line:
p=6;
Build a list of primes from the 3rd to $p-1$:
plist=Table[Prime[n],{n,3,p-1}];
Then build a list as follows:
bmod=Outer[Mod,{3*Prime[p]},plist]
Here's the code so far with the…
Elem-Teach-w-Bach-n-Math-Ed
- 707
- 3
- 11
1
vote
2 answers
Modular arithmetic in Mathematica?
I want to implement something like 1 + 1 = 0; i.e., simple modular arithmetic in Mathematica.
This seems like it should be a really easy built-in option, but I can't find any info on it anywhere. I think probably I'm just overlooking…
quantum_loser
- 329
- 1
- 9
0
votes
1 answer
Solving for $d$ in $x= E^d \bmod(n)$
With regards to Public Key Cryptography, I have been tasked with the problem of attacking some information given in an assignment and discovered a private key used to digitally sign a…
Matt
- 19
0
votes
1 answer
Eliminate an expression with Mod operation
The target below should equal 0, since 2x + c = a + b + c = 6c, and Mod[6c,3] == 0
But Mathematica seems to be unable to simplify this expression containing Mod?
It says "target-1/4\ Mod[c+2\ x,3] is not a well-formed equation."
Eliminate[{a == b +…
worldterminator
- 123
- 4
-2
votes
1 answer
Want code for a modular operation
Given numbers a1 and a2 and a positive integer k, such that a3 = Mod[a1 a2, k], a4 = Mod[a1 a3, k] and so on, I want the Mathematica code that can compute the value of {a1, a2, a3, a4, ..., an} stopping at a point where a particular condition is…
myg
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- 6