Issue in Rmpq_z_div(r, z, q) when z=0

[trizen]

Hi Rob,

There is a minor issue in Rmpq_z_div(r, z, q) when z holds the value 0.

use strict;
use warnings;

use Math::GMPz;
use Math::GMPq;

my $r = Math::GMPq->new('0');
my $z = Math::GMPz->new('0');
my $q = Math::GMPq->new('42');

Math::GMPq::Rmpq_z_div($r, $z, $q);

print $r;                        # should print '0'

Output:

[1]    31405 floating point exception (core dumped)  perl x.pl

[sisyphus]

From: Daniel Șuteu Sent: Monday, April 17, 2017 9:31 AM To: sisyphus/math-gmpq Cc: Subscribed Subject: [sisyphus/math-gmpq] Issue in Rmpq_z_div(r, z, q) when z=0 (#3) Hi Rob,

There is a minor issue in Rmpq_z_div(r, z, q) when the z holds the value 0.

Duh ... probably shouldn't multiply a denominator by zero. I think (untested) this will work correctly: void Rmpq_z_div(mpq_t * rop, mpz_t * z, mpq_t * op) { if(rop != op) mpq_set(*rop, *op); mpq_inv(*rop, *rop); mpz_mul(mpq_numref(*rop), mpq_numref(*rop), *z); mpq_canonicalize(*rop); } But I also need to catch the "divide-by-zero" cases - in many (if not all) of the division routines. The ones I tested all crash on "divide-by-zero" which is not very helpful. I expect that the above reworking of Rmpq_z_div will also crash if op is zero, irrespective of the value of z. I just need to insert code that calls a croak() whenever a "divide-by-zero" is about to occur. I'll do that over the next couple of days, write some tests that check that "divide-by-zero" is being caught, and then push another release to CPAN. Cheers, Rob

[sisyphus]

I've just pushed Math-GMPq-0.45 to CPAN.
Hopefully this fixes the issue (along with the divby0 issues I mentioned above).
Cheers,
Rob

[trizen]

Hi Rob,

Fix confirmed here. Thank you very much.

Regards,
Daniel