add test for spherical_coslat_differential

[rjnrohit]

Description

1. Previously, cross generate errors for some coordinate system i.e previous version can't able to identify bu::conversion_factor(plane_angle, meter for cross(cartesian point, spherical point) ) in calculation part of code.
2. Now cross returns cross product in requested representation( It returns correct units for every representation).
3. Updated unit_vector function in arithmetic.hpp to return a unit vector directed from one point to another point.
4. Update tests to check the cross product of representation.
5. Test added for spherical_coslat_differential representation, update io.hpp header to support differential motion object.
   6.Now, cross can also calculate cross product of differential motion objects too.

References

Tasklist

• Add test case(s)
• Ensure all CI builds pass
• Review and approve

[rjnrohit]

@lpranam please review this PR and provide feedback to me. #123

[rjnrohit]

Function to return current differential of this object. By doing this we are able to calculate cross of differential objects.

[sarthak2007]

Look at #123 (comment)

[sarthak2007]

You should submit different PRs for different contexts. Like in this case, separate PRs should be there for unit_vector, magnitude, tests.
Also, you should push after squashing the commits.

[sarthak2007]

As you have made this function to support differentials, you should name the arguments differential1 and differential2 instead of representation1 and representation2 to maintain uniformity in the library. And change this whole function accordingly.

[rjnrohit]

ok. I'll do that.

[sarthak2007]

What is the need of this function? get_differential is already there in base_differential.hpp.

[rjnrohit]

By doing this we can extend all arithmetic function to work for differentials as well. Otherwise, we may get a conflict of .get_point() in all arithmetic functions.

[sarthak2007]

I guess this will help in magnitude function. But functions like sum, mean, difference, dot use make_cartesian_representation() and hence can't be extended to work for differentials by defining get_point for differential.

[rjnrohit]

It'll also help to calculate cross for two differential classes or one representation class and one differential class. In the code where we used
bg::transform(cartesian1.get_point(), tempPoint1); bg::transform(cartesian2.get_point(), tempPoint2);

[rjnrohit]

@sarthak2007 I'm closing this PR. I have created a separate PR #127 for the extension of arithmetic functions to support differential systems.

[rjnrohit]

You should submit different PRs for different contexts. Like in this case, separate PRs should be there for unit_vector, magnitude, tests.
Also, you should push after squashing the commits.

Ok. I'll create a new PR for every context.