Re: math:mod
- Posted by bill May 12, 2012
- 1348 views
Not exactly:
Modulus mathmatically:
- x modulus 0: is undefined.
- x modulus n: is a number in the range 0 .. |n|-1
- where |a| = absolute value of a.
Hence the statement:
- The result is non-negative and has lesser magnitude than divisor.
The mod function uses floored division which would
mean that:
-9 mod 5 = floor(-1.8) = -2 * 5 + 1 => 1 -9 mod -5 = floor(1.8) = 1 * -5 + -4 => -4 9 mod -5 = floor(-1.8) = -2 * -5 + -1 => -1 9 mod 5 = floor(1.8) = 1 * 5 + 4 => 4
As -1 mod 5 equals 4 mod 5 and
- -4 mod 5 equals 1 mod 5
the sign of the dividend is irrelevant.
Clearly the mod function is not modulus.
and secondly the documentation is seriously
misleading.
This needs to be fixed.
