Message-ID: <oprn4v5zz2faouaq@200.24.8.4>
Date: 2003-04-24T12:40:37Z
From: Kenneth Cabrera
Subject: How %% and %/% work on negative numbers?
Hi R developers and users:
How do "mod" and "integer division" work with negative integers on R?
I mean why you obtain different results if you work on C or anywhere else
and in R?
I see R guarantees that `x == (x %% y) + y * ( x %/% y )', but
it looks rare the individual (x %% y) and y * ( x %/% y ) results when
you use negative integers, because is contradictory to what is expected,
e.g.
-17 mod 15 should be -2, but R shows 13 and
-17 integer division 15 should be -1, but R shows -2
because the reconstruction formula should be 15*(-1)+(-2) == -17
Or am I wrong?
Thank you for your help
Kenneth