seepee wrote:
> On Thu, 21 Dec 2006 09:12:47 +0200, seepee wrote:
>
>   
>> Does anyone know of a functional Matrix math class for ruby that could
>> multiply, add and substract 3x2 or larger matrices.
>>
>> The matrix.rb that is in Ruby API cannot multiply anything larger than 2x2
>> matrices, which makes it useless for 2D or 3D graphics (for instance).
>>
>> SP
>>     
>
> Problem:
> go to terminal, and type "irb" or "irb1.8"
>
>   
>> require 'matrix' #or require >rubylibrarypath/matrix.rb
>> p Matrix[ [25, 93, 33], [0, -1, 66] ] * Matrix[ [1, 53, 33], [1, -21, 77]
>>     
>
> ExceptionForMatrix::ErrDimensionMismatch: Matrix dimension mismatch
>         from /usr/lib/ruby/1.8/matrix.rb:466:in `*' from (irb):4
>
> ??
>   
Yes, it's because you cannot multiply a 2x3 matrix with another 2x3 
matrix.... try:

Matrix[ [25, 93, 33], [0, -1, 66] ] * Matrix[ [1, 53, 33], [1, -21, 77]].transpose


Julien