id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
9717	Boost math library on PPC64 has thousands of errors	Tony Reix <tony.reix@…>	John Maddock	"Hi,

I'm trying to port Boost 1.55 on PowerPC64 BE and LE.
Thousands of errors appear with math library.

Investigation one test (bessel_zeros_example_1) which loops, I see by means of gdb the following:
  boost::math::cyl_bessel_j_zero< double, .....
  boost::math::detail::cyl_bessel_j_zero_imp<__float128, .....

This  ""__float128"" seems erroneous.
However, looking at boost/math/special_functions/bessel.hpp code, I see that this type is chosen at compilation time, by means of:
 typedef typename policies::evaluation<result_type, Policy>::type value_type;
and it is a nightmare to understand why the compiler did choose __float128. Unless gdb is showing nuts ?

Exact test is:
bin.v2/libs/math/example/bessel_zeros_example_1.test/gcc-4.8.2/debug/bessel_zeros_example_1

Comparing execution path of this test code in PPC64/BE to Intel64, I see some floor() value computed differently on the 2 systems, and leading the test program to enter a wrong path and stay stucked in an infinite loop.

There is some fundamental error, hidden by compiler which compiles templates and gives me no hint.

I need help to determine what is wrong with Boost math on PPC64.

Tony"	Bugs	new	To Be Determined	math	Boost 1.55.0	Problem