Re: bad mod function

[Rik]

On 06/19/2018 08:45 AM, address@hidden wrote:

Subject:

bad mod function - Matlab

From:

Vic Norton <address@hidden>

Date:

06/19/2018 08:08 AM

To:

Octave Maintainers List <address@hidden>

List-Post:

<mailto:address@hidden>

Content-Transfer-Encoding:

quoted-printable

Precedence:

list

MIME-Version:

1.0 (Mac OS X Mail 10.3 \(3273\))

Message-ID:

<address@hidden>

Content-Type:

text/plain; charset=utf-8

Message:

5

The mod function in my Mac system is not working.
———————————————————————————————————

Here is essentially the same script run with Matlab.
This is the way the mod function is supposed to work

%% testmod.m  - test the mod function
%    with Matlab '9.3.0.713579 (R2017b)'

fprintf('-- bad mod function? --\n');
for i = 1 : 11
 fprintf('%4d', i);
 if mod(i, 5) == 1; fprintf('\n'); end
end
fprintf('-- good mod function --\n');
for i = 1 : 11
 fprintf('%4d', i);
 if modxy(i, 5) == 1; fprintf('\n'); end
end

function v = modxy(x, y)  % to replace the faulty mod function
 v = x - y .* floor (x ./ y);
end

%{

testmod

-- bad mod function? --
  1
  2   3   4   5   6
  7   8   9  10  11
-- good mod function --
  1
  2   3   4   5   6
  7   8   9  10  11
%}

For the moment, skip the for loop and more complicated code.  What does the following return when entered on the Octave command line?

mod (5,5)
mod (6,5)
mod (7,5)

It should be 0, 1, and 2 respectively.  If it isn't then there is something wrong with the installation as Dmitri suggested.

--Rik