Subject: Re: [boost] [multiprecision] Are these types suitable as numeric types for unit tests?
From: John Maddock (john_at_[hidden])
Date: 2013-06-08 04:39:39
> I'm writing new numeric types, and my unit tests use MPL lists of numeric
> types. I usually use stuff like int, unsigned, and double, but now I'm
> adding cpp_int and cpp_dec_float_50. Those types were OK when I was just
> doing type equalities and sizeof checks. Now I'm doing tests that use
> objects of those types and I'm getting problems.
> typedef boost::mpl::list<int, unsigned, cpp_int> test_integer_types;
> typedef boost::mpl::list<double, cpp_dec_float_50> test_floating_types;
> I'm getting warnings about integer overflow. The problem is at Line 59 of
> boost/test/tools/detail/print_helper.hpp. It sets an output stream's
> precision based on the digits given by std::numeric_limits.
That's harmless but annoying: it's because
std::numeric_limits<cpp_int>::digits is INT_MAX. The stream precision isn't
ever used by integer types anyway...
> This time it's an error, at Line 59 of
> boost/test/tools/floating_point_comparison.hpp. There no (close enough)
> matching function for "fpt_abs" from some
> "boost::multiprecision::detail::expression<..." type. (It was truncated
> by the display. I don't know how to get a clean print-out of errors from
> Code::Blocks.) I'm guessing the expression template setup is screwing
> things up.
Yes, it's because Boost.Test can't be used with expression template enabled
types. It's a known issue, and I've added a patch for this:
https://svn.boost.org/trac/boost/ticket/8272, but Genediiy seems to be MIA
at present :-(
Do you particularly want to test with expression-template enabled types (I
reaslise there are cases when you do)? If not then you could use
multiprecision types that have expression templates turned off and that
should fix things.
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