# Mod function returns decimal value?

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SNEHA P S on 20 Jul 2017
Answered: Jan on 20 Jul 2017
I was trying to generate some random sequence using chaotic tent map. After generating some values i would like to convert them to a higher value which helps to perform some operation with pixel values of an image. So i used an equation "s = mod((y * (10^10)),256);" where y is the generated sequence using tent map. But after performing this mod operation the result i got was weird because it outputs decimal values like 0, 240.959269494109, 225.918538988219, 210.877808482386, 195.837077976437. Why this happens? The output of mod operation should be an integer, right?? Instead of Modulo i tried rem() function also. The result was same. Please help me.

Jan on 20 Jul 2017
The output of mod operation should be an integer, right??
No.
The output of modulo operation returns the remainder value, right?
Yes.
The remainder is the rest after the division. 9.83 divided by 3 = 3*3 + 0.83, such that 0.83 is the remainder - and this need not be an integer.

David Goodmanson on 20 Jul 2017
Hi sneha,
You have already demonstrated that mod does not necessarily output integers. Something like
s = mod(round(y*10^10),256)
would.
David Goodmanson on 20 Jul 2017
Edited: David Goodmanson on 20 Jul 2017
Suppose both numbers here are positive for simplicity. By definition the remainder is the positive quantity that is left over after you evenly divide the first number by the second as many times as possible.
6.7 = 3*2 + .7
>> mod(6.7,2)
ans = 0.7000
Naturally if both numbers are integers the remainder will be an integer. But that's not what you had, and that's why I suggested using the round command.