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Subject: Re: funny problem about the precision of matrix transpose and inverse.
Date: Wed, 31 Oct 2012 04:15:09 +0000 (UTC)
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"Steven_Lord" <slord@mathworks.com> wrote in message <k6omou$54f$1@newscl01ah.mathworks.com>...
> 
> As an additional note for the original poster, if you're trying to solve a 
> system of linear equations do NOT repeat NOT construct the normal equations 
> and invert.
> 
> http://en.wikipedia.org/wiki/Linear_least_squares_%28mathematics%29#Computation
> 
> Use the backslash operator instead.
> 
> http://www.mathworks.com/help/matlab/ref/mldivide.html
> 

Yeah, I used the backslash in my code.

I'm linearizing a nonlinear inversion problem and solving A*m=b in a least squares sense, where A is the jacobian matrix. 

Backslash seems provide no help.  I still get a warning that the matrix is badly scaled or nearly singular and sometimes it gives rise to NaNs.