id	summary	reporter	owner	description	type	status	milestone	component	version	severity	resolution	keywords	cc
11272	Incorrect use of abs() function in libs/math/example/normal_misc_examples.cpp	Quentin Armitage <quentin@…>	John Maddock	"When running normal_misc_examples, it produces the following error:
{{{
If we want the 0.0500 th quantile to be located at 2.90, would need a standard deviation of 0.00

Message from thrown exception was:
   Error in function boost::math::normal_distribution<double>::normal_distribution: Scale parameter is 0, but must be > 0 !
}}}

The reason for this is line 373:
{{{
double sd95 = abs((x - mean)) / qp;
}}}
where the abs() function is the C function which takes an int parameter. Passing it the double (x - mean) returns 0.

As a temporary workaround, I have modified the code to
{{{
double sd95 = (x - mean) / qp;
if (sd95 < 0)
    sd95 = -sd95 ;
}}}
and this resolves the problem."	Bugs	closed	To Be Determined	math	Boost 1.57.0	Problem	fixed