From 8237156ffb390b38c55863d1b14f246af8a1c19c Mon Sep 17 00:00:00 2001 From: Mattias Andrée Date: Sat, 5 Mar 2016 16:36:56 +0100 Subject: More detailed description of division and modulus MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Signed-off-by: Mattias Andrée --- man/zmod.3 | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'man/zmod.3') diff --git a/man/zmod.3 b/man/zmod.3 index 9c6e72b..a6cd21d 100644 --- a/man/zmod.3 +++ b/man/zmod.3 @@ -24,11 +24,22 @@ Mod .P The result .RI ( remainder ) -is always non-negative. +is always non-negative. To be more precise, +a Mod b = |a| Mod |b| for all integers a +and b. .P It is safe to call .B zmod with non-unique parameters. +.SH RATIONALE +There are many ways to define modulus with +negative integers. You have to select how the +signness is selected, and when to invert +(in respect to modulated addition) the remainder. +The simplest way to implement modulus is to +ignore the sign of the operands. This solution +also makes it very easy for those that which +to write a wrapper that changes the definition. .SH SEE ALSO .BR zdivmod (3), .BR zstr (3), -- cgit v1.2.3-70-g09d2