Re: [eigen] cwiseop_1 test failure

[Gael Guennebaud <gael.guennebaud@xxxxxxxxx>]

even better, if you comment all the lines *after* the first test which fails :

VERIFY_IS_APPROX(m4.setConstant(s1), m3);

then no error at all !!!

gael

On Fri, Jun 11, 2010 at 2:57 PM, Gael Guennebaud
<gael.guennebaud@xxxxxxxxx> wrote:
> to be honest I really think this is a GCC issue like the one I
> reported here a couple of months ago:
>
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=42255
>
> At that time this bug only showed up with when coverage testing was
> enabled, but it seems to me we are now hitting the same bug with -O2
> only.
>
> Indeed, I rewrote the test_ei_isApprox function like this:
>
> EIGEN_DONT_INLINE void foo(bool& x) {x=x;}
>
> template<typename Type1, typename Type2>
> EIGEN_DONT_INLINE bool test_ei_isApprox(const Type1& a, const Type2& b)
> {
>  bool ret = a.isApprox(b, test_precision<typename Type1::Scalar>());
>  foo(ret);
>  return ret;
> }
>
> and that fixed the issue (both the failure and valgrind's issue).
>
> However, if I comment the line foo(ret);, then the issue shows up.
> Note that here Type1 == Type1 == Matrix<float, 1, 1>. It cannot be
> more trivial.
>
> I even get a segfault at the line return a.isApprox(b); when doing:
>
> template<typename Type1, typename Type2>
> inline bool test_ei_isApprox(const Type1& a, const Type2& b)
> {
>  bool ret;
>  std::cerr << a << " == " << b << " " << (a-b) << " " << (ret =
> a.isApprox(b)) << "\n";
>  return a.isApprox(b);
> }
>
> Really strange.
>
> gael
>
> On Fri, Jun 11, 2010 at 12:41 PM, Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx> wrote:
>> Hello,
>>
>> I had a quick look at the cwiseop_1 test, which according to the dash board
>> fails on both Gael's and my computer but only with GCC 4.3.
>>
>> I did not get very far and I have other commitments at the moment (and I've
>> also run out of ideas), but perhaps somebody can continue from here.
>>
>> The offending line is
>>
>>   VERIFY_IS_APPROX(m4.setConstant(s1), m3);
>>
>> Here, m3 and m4 are of type MatrixType = Matrix<1,1,float>, s1 is a random
>> float, and m3 is set to MatrixType::Constant(1,1,s1).
>>
>> I did not manage to get an self-contained test case, though given more time
>> this should be possible.
>>
>> valgrind reports:
>> Use of uninitialised value of size 4
>>    at 0x804A35F: bool Eigen::test_ei_isApprox<Eigen::Matrix<float, 1, 1, 0,
>> 1, 1>, Eigen::Matrix<float, 1, 1, 0, 1, 1> >(Eigen::Matrix<float, 1, 1, 0,
>> 1, 1> const&, Eigen::Matrix<float, 1, 1, 0, 1, 1> const&) (in .../cwiseop_1)
>>    by 0x804AE1E: void cwiseops<Eigen::Matrix<float, 1, 1, 0, 1, 1>
>>>(Eigen::Matrix<float, 1, 1, 0, 1, 1> const&) (in .../cwiseop_1)
>>    by 0x8049DB9: test_cwiseop() (in .../cwiseop_1)
>>    by 0x804A0EA: main (in .../cwiseop_1)
>>
>> The error persists if I replace
>>
>>   VERIFY_IS_APPROX(m4.setConstant(s1), m3);
>>
>> by
>>
>>   VERIFY(test_ei_isApprox(m4.setConstant(s1), m3));
>>
>> However, the error goes away if I replace it by
>>
>>   VERIFY(m4.setConstant(s1).isApprox(m3, test_precision<typename
>> MatrixType::Scalar>()));
>>
>> As far as I see, this is just inlining the definition of test_ei_isApprox,
>> so I don't see why this makes a difference.
>>
>>
>> Jitse
>>
>>
>>
>>
>