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Summary: | Add vectorization of sqrt for doubles | ||
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Product: | Eigen | Reporter: | panda-34 <anikin> |

Component: | Core - vectorization | Assignee: | Nobody <eigen.nobody> |

Status: | RESOLVED FIXED | ||

Severity: | enhancement | CC: | chtz, gael.guennebaud, jacob.benoit.1 |

Priority: | Normal | ||

Version: | 3.2 | ||

Hardware: | x86 - SSE | ||

OS: | All | ||

Whiteboard: | |||

Bug Depends on: | |||

Bug Blocks: | 558 |

Description
panda-34
2013-08-08 20:34:26 UTC
I fully agree. I guess the main problem with the fast implementation are wrong results for negative values (should be NaN), +inf (should be inf) and denormalized values (rsqrt treats them as 0.0f, resulting in inf which leads to a NaN after the refinement). Related discussion on the ML (old!): http://listengine.tuxfamily.org/lists.tuxfamily.org/eigen/2009/03/msg00114.html And I agree with Christoph, the main pb is not on the accuracy but on the handling of negative, inf and denorms. https://bitbucket.org/eigen/eigen/commits/97d9a7772106/ Changeset: 97d9a7772106 User: ggael Date: 2013-08-19 16:02:27 Summary: Fix bug 642: add vectorization of sqrt for doubles, and make sqrt really safe if EIGEN_FAST_MATH is disabled -- GitLab Migration Automatic Message -- This bug has been migrated to gitlab.com's GitLab instance and has been closed from further activity. You can subscribe and participate further through the new bug through this link to our GitLab instance: https://gitlab.com/libeigen/eigen/issues/642. |