On Wed, Feb 29, 2012 at 3:55 PM, Miguel Negrao
<miguel.negrao-li...@friendlyvirus.org> wrote:
> Would an automated “blind" search algorithm possibly

Speaking of that, you probably want to search the list archives for a
thread I started in 2009 titled:

"A stupid optimizer for irregular ambisonic layouts"

In it I provide the source for a simplistic decoder that uses a
generic open source blackbox non-linear optimizer library with a
simple objective to make matrixes.

I like the generic optimization approaches _more_ than more
mathematically elegant closed form solutions because it's easy to play
around with the objective functions— and usually any change to the
objective makes your closed form solutions need to start from scratch.

The URL I gave is dead, but I found what I _believe_ is the same file
and put it a location which should be a bit longer lasting.

https://people.xiph.org/~greg/ambisonics/ambi_opt.c

(compilation is just "gcc -std=c99 -O3 -o ambi_opt ./ambi_opt.c -lm -lnlopt")

Giving a brief glance at the code, now with several more years of
experience with optimization— and I see that my objective function
appears differentiable.  If I were to do this again I'd probably use a
C++ reverse mode automatic differentiation library, so that I could
get a version of the objective with gradients.

My email archives indicate that Aaron Heller made a version with a
bunch of improvements like RME rE optimization, and adding direction
mismatch between rE and rV as part of the objective.  Somewhere I had
some version with support for higher orders and 3d but I don't know
where that is right now.

There are a lot of things you can do starting from a simple framework like this.
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