[racket] Thanks for Math

Jens Axel Søgaard wrote most of the linear algebra functions; he's the 
high-caliber guy to thank for `matrix-solve'. In case he doesn't pop in 
here to say it himself, you're very welcome. :)

Neil ⊥

On 04/22/2013 01:21 PM, Richard Cleis wrote:
> Recently I used it for estimating orientation parameters of
> telescopes. Inputs are the locations of stars, outputs are telescope
> coordinates, parameters describe the relationship of axes to each other
> and to the earth.
>
> In matrix-solve, MX=B are
> M : J[transpose]J, where the J matrix is filled with numerically
> computed derivatives of each parameter vs outputs.
>
> B : J[transpose]E, where E is filled with the errors in each axis as
> measured by observing stars
>
> X : the changed in parameters that are to be solved on each iteration of
> the estimator
>
> Due to numerous orthogonal components and parallel parameters (for
> certain pointing directions), the matrix library has to be rigorously
> written, else the iterations die of round-off errors etc. I had several
> choices, but given the high caliber people that write Racket code, I
> figured I could go with matrix-solve and expect it to work.
>
> rac
>
>
> On Apr 21, 2013, at 11:11 AM, Joe Gilray wrote:
>
>> Yes, the math library is awesome.  Many thanks.
>>
>> Richard, what are you using it for? (if you are liberty to say, of
>> course).
>>
>> -joe
>>
>>
>> On Sat, Apr 20, 2013 at 8:28 PM, Richard Cleis <rcleis at me.com
>> <mailto:rcleis at me.com>> wrote:
>>
>>     Thanks for the math library. I started using some of the linear
>>     algebra functions for my paid programming, and have had zero
>>     trouble with any of it. Matrix-solve works like a dream, and the
>>     docs are on the mark.
>>
>>     I have to wonder what would happen if a program manager were
>>     looking over my shoulder on the rare occasion that I commit a
>>     Contract Violation for issues like non-invertible matrices. PMs
>>     are a humorless lot in regards to violation of contractual terms.
>>
>>     rac
>>
>>
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