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Bug 1424

Summary:	Eigen::Matrix< unsigned int >::setLinSpaced
Product:	Eigen	Reporter:	simon.floery
Component:	Core - general	Assignee:	Nobody <eigen.nobody>
Status:	RESOLVED FIXED
Severity:	Compilation Problem	CC:	chtz, fl.gagliardi, gael.guennebaud, jacob.benoit.1
Priority:	Normal
Version:	3.3 (current stable)
Hardware:	All
OS:	Windows
Whiteboard:

Description simon.floery 2017-05-02 12:23:48 UTC

Dear all,

In both VS2015 and VS2017, the following code snippet fails to compile with eigen-3.3.3.:

	Eigen::Matrix< unsigned int, 1, 5 > m;
	m.setLinSpaced(0u, 7u);

VS2015 complains:
Severity	Code	Description	Project	File	Line
Error	C2668	'abs': ambiguous call to overloaded function	eigen_vs2015	c:\eigen-3.3.3\eigen\src\core\mathfunctions.h	1066

With eigen-3.2.8, we do not get any errors.

thanks, Simon

Comment 1 Flavio Gagliardi 2017-05-05 12:14:34 UTC

(In reply to simon.floery from comment #0)
> Dear all,
> 
> In both VS2015 and VS2017, the following code snippet fails to compile with
> eigen-3.3.3.:
> 
> 	Eigen::Matrix< unsigned int, 1, 5 > m;
> 	m.setLinSpaced(0u, 7u);
> 
> VS2015 complains:
> Severity	Code	Description	Project	File	Line
> Error	C2668	'abs': ambiguous call to overloaded function	eigen_vs2015
> c:\eigen-3.3.3\eigen\src\core\mathfunctions.h	1066
> 
> With eigen-3.2.8, we do not get any errors.
> 
> thanks, Simon

I am not an expert and I don't know if a better solution exists. Personally, I solved this problem in GCC 7.1 by adding a template specialization for unsigned int and long unsigned int in MathFunctions.h

after the function

template<typename T>
EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE
typename NumTraits<T>::Real abs(const T &x) {
  EIGEN_USING_STD_MATH(abs);
  return abs(x);
}


I added 

template<>
EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE
typename NumTraits<long unsigned int>::Real abs(const long unsigned int& x) {
  return x;
}

template<>
EIGEN_DEVICE_FUNC EIGEN_ALWAYS_INLINE
typename NumTraits<unsigned int>::Real abs(const unsigned int& x) {
  return x;
}

Comment 2 Gael Guennebaud 2017-06-09 10:02:01 UTC

Thank you for the report, fixed:

https://bitbucket.org/eigen/eigen/commits/cfb064a552e8/ (devel)
https://bitbucket.org/eigen/eigen/commits/15f6a8f430ab/ (3.3)

Comment 3 Nobody 2019-12-04 16:58:43 UTC

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