CODEWITHSUNDEEP
c++eigenpoint-cloud-library
SPS
SPS

Reputation: 475

Eigen::vector::normalize precision

I'm using Eigen library, v.3.2.1. I'm calculating some normals of some planes. Then I want to normalize them. My problem is that for some normals the calculated norm is not precisely 1.00000, that is:

normalA=(0.0000,0.0000,1165.0521)----->normalA.normalize()=(0.0000,0.0000,1.0000)

normalB=(0.0000,0.0000,1165.0524)----->normalB.normalize()=(0.0000,0.0000,1.0000)

normalC=(0.0000,0.0000,312.17474)----->normalC.normalize()=(0.0000,0.0000,1.0000)

normalD=(0.0000,0.0000,2017.9299)----->normalD.normalize()=(0.0000,0.0000,0.99999994)

My problem is that when I compare normalA with normalD c++ return false and my algorithm fails, i.e if(normalA==normalD).

How could I solve this problem? Are there some function to avoid this simple problem? I'm sorry, but I'm a beginner: teach me!

Upvotes: 1

Views: 8395

Answers (1)

Philipp Schlehuber
Philipp Schlehuber

Reputation: 21

As already pointed out, the error is caused by floating point arithmetic. This post

[1]: https://stackoverflow.com/questions/15051367/how-to-compare-vectors-approximately-in-eigen

Provides a nice way to cope with your problem.

Best regards

Upvotes: 2

Related Questions