# Re: Setting precision in Ruby-GSL calculations?

**URL:** <https://www.ruby-forum.com/t/re-setting-precision-in-ruby-gsl-calculations/100740>\
**Category:** Ruby\
**Created:** [July 31, 2006, 8:11pm UTC](https://www.ruby-forum.com/t/re-setting-precision-in-ruby-gsl-calculations/100740 "2006-07-31T20:11:05Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\
**Post date:** [July 31, 2006, 8:11pm UTC](https://www.ruby-forum.com/t/re-setting-precision-in-ruby-gsl-calculations/100740/1 "2006-07-31T20:11:05Z")

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Dear Ed, dear Yoshiki,

thanks for your replies… I am now able to reproduce your results in  
Ruby-Gsl,  
(eliminating some typos),

and I’ve learnt that there are some conflicting definitions of singular  
value  
decompositions, which lead to part of my difficulties:

Ruby-Gsl defines these as M= U S V^tr,  
where U can have uneven dimensions, but many authors require U to  
be square (and softwares, eg. Mathematica) - then it has the dimensions  
of the image space of the linear mapping M defines … this definition  
makes  
it easier to calculate pseudo-inverses, as it doesn’t lead to dimension  
problems  
in multiplication…

I still don’t know why I don’t get singular values to higher precision  
…  
does one have to convert to Float or something ?

Thank you for your time,

Best reagrds,

Axel