Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0 |

[ Thread Index | Date Index | More lists.tuxfamily.org/eigen Archives ]

*To*: "eigen@xxxxxxxxxxxxxxxxxxx" <eigen@xxxxxxxxxxxxxxxxxxx>*Subject*: Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0*From*: Jitse Niesen <jitse@xxxxxxxxxxxxxxxxx>*Date*: Sat, 17 Jul 2010 22:52:43 +0100 (BST)

On Sat, 17 Jul 2010, Benoit Jacob wrote:

Another reason why we decided not to expose condition numbers in Eigen is that for the main purpose they're used for, namely checking if a result is reliable, there is a better approach which is: check the result itself. For example, if you want to check how accurate your matrix inverse is, just compute matrix*inverse and see how close it is to the identity matrix. Nothing beats that! When it comes to more general solving with potentially non full rank matrices, this is even better, because the condition number of the lhs matrix alone doesn't tell all you need to know (it also depends on your particular rhs), so the approach we're recommending in Eigen, to compute lhs*solution and compare with rhs, is the only way to know for sure how good your solution is.

Cheers, Jitse

**Follow-Ups**:**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Benoit Jacob

**References**:**[eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Robert Lupton the Good

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Christoph Hertzberg

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Gael Guennebaud

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Robert Lupton the Good

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Benoit Jacob

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Aron Ahmadia

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Benoit Jacob

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Benoit Jacob

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Aron Ahmadia

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Aron Ahmadia

**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0***From:*Benoit Jacob

**Messages sorted by:**[ date | thread ]- Prev by Date:
**Re: [eigen] [history] 4 years already!!** - Next by Date:
**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0** - Previous by thread:
**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0** - Next by thread:
**Re: [eigen] Problem inverting a Matrix4f with Eigen 2.0.0**

Mail converted by MHonArc 2.6.19+ | http://listengine.tuxfamily.org/ |