Line2.Collinear function not work right.

[0smile]

Environment

• OS Version: <Ubuntu 20.04>
• Source or binary build?
  <binary, math6.8>

Description

• Expected behavior: I'm using the function 'Collinear' of the class 'Line2'. Ideally it should calculate the cross product of two lines using the function Line2.CrossProduct, and than compare the product with 0 using the math::equal function. However it doesn't work right.
• Actual behavior: While I make from the source code, it shows 'error: no matching function for call to ‘equal(double, int, double&)’. I think it is because that Line2.CrossProduct returns a double number, but the math::equal can not compare the double with a int 0.

Steps to reproduce

1. type: line1.Collinear(line2)
2. make from the source code.

Output

In file included from /usr/include/ignition/math6/ignition/math.hh:41,
                 from /home/shaw/Desktop/ignition/math/test.cpp:3:
/usr/include/ignition/math6/ignition/math/Line2.hh: In instantiation of ‘bool ignition::math::v6::Line2<T>::Parallel(const ignition::math::v6::Line2<T>&, double) const [with T = int]’:
/usr/include/ignition/math6/ignition/math/Line2.hh:140:22:   required from ‘bool ignition::math::v6::Line2<T>::Collinear(const ignition::math::v6::Line2<T>&, double) const [with T = int]’
/home/shaw/Desktop/ignition/math/test.cpp:14:32:   required from here
**/usr/include/ignition/math6/ignition/math/Line2.hh:126:27: error: no matching function for call to ‘equal(double, int, double&)’**
  126 |         return math::equal(this->CrossProduct(_line),
      |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
  127 |             static_cast<T>(0), _epsilon);
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/ignition/math6/ignition/math/graph/Vertex.hh:29,
                 from /usr/include/ignition/math6/ignition/math/graph/Edge.hh:28,
                 from /usr/include/ignition/math6/ignition/math.hh:23,
                 from /home/shaw/Desktop/ignition/math/test.cpp:3:
/usr/include/ignition/math6/ignition/math/Helpers.hh:556:17: note: candidate: ‘template<class T> bool ignition::math::v6::equal(const T&, const T&, const T&)’
  556 |     inline bool equal(const T &_a, const T &_b,
      |                 ^~~~~
/usr/include/ignition/math6/ignition/math/Helpers.hh:556:17: note:   template argument deduction/substitution failed:
In file included from /usr/include/ignition/math6/ignition/math.hh:41,
                 from /home/shaw/Desktop/ignition/math/test.cpp:3:
/usr/include/ignition/math6/ignition/math/Line2.hh:126:27: note:   deduced conflicting types for parameter ‘const T’ (‘double’ and ‘int’)
  126 |         return math::equal(this->CrossProduct(_line),
      |                ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
  127 |             static_cast<T>(0), _epsilon);
      |             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~
make[2]: *** [CMakeFiles/test.dir/build.make:63: CMakeFiles/test.dir/test.cpp.o] Error 1
make[1]: *** [CMakeFiles/Makefile2:76: CMakeFiles/test.dir/all] Error 2
make: *** [Makefile:84: all] Error 2

[scpeters]

can you provide a complete c++ file so that I can reproduce the failure?

[0smile]

Thanks for your concern!

…

________________________________ 发件人: Steve Peters ***@***.***> 发送时间: 2021年7月11日 5:51 收件人: ignitionrobotics/ign-math ***@***.***> 抄送: 0smile ***@***.***>; Author ***@***.***> 主题: Re: [ignitionrobotics/ign-math] Line2.Collinear function not work right. (#213) can you provide a complete c++ file so that I can reproduce the failure? ― You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub<#213 (comment)>, or unsubscribe<https://github.com/notifications/unsubscribe-auth/AMU6ELWIMVLLNTY3LNXDAXTTXEWPLANCNFSM5AE4S63Q>. cmake_minimum_required(VERSION 3.5 FATAL_ERROR) # Find the Ignition-Math library set(IGN_MATH_VER 6) find_package(ignition-math${IGN_MATH_VER} REQUIRED) add_executable(test test.cpp) target_link_libraries(test ignition-math${IGN_MATH_VER}::ignition-math${IGN_MATH_VER})

[chapulina]

@0smile , are you able to provide a minimal failing example?

[WagnerMarcos]

I have come across this issue, and I am pushing a fix in this PR, with this issue described in the Line2 Issues and notes section. Using 0. (A float type 0) should fix the problem. This issue appears when using a Line2 with the double template