Determinant of Large Matrix

[Tommy Nordgren]

On 6 jun 2007, at 13.10, James Stroud wrote:

> Hello All,
>
> I'm using numpy to calculate determinants of matrices that look like
> this (13x13):
>
> [[ 0.  1.  1.  1.  1.  1.  1.  1.  1.  1.  1.  1.  1.  1.]
>   [ 1.  0.  1.  4.  1.  9.  4.  4.  1.  1.  4.  9.  4.  9.]
>   [ 1.  1.  0.  1.  4.  4.  9.  9.  4.  4.  1.  4.  1.  4.]
>   [ 1.  4.  1.  0.  9.  1.  4.  4.  9.  1.  4.  1.  4.  1.]
>   [ 1.  1.  4.  9.  0.  4.  4.  4.  1.  4.  1.  9.  4.  9.]
>   [ 1.  9.  4.  1.  4.  0.  4.  4.  9.  4.  1.  1.  4.  1.]
>   [ 1.  4.  9.  4.  4.  4.  0.  1.  1.  1.  9.  1.  9.  4.]
>   [ 1.  4.  9.  4.  4.  4.  1.  0.  4.  1.  9.  4.  4.  1.]
>   [ 1.  1.  4.  9.  1.  9.  1.  4.  0.  4.  4.  4.  4.  9.]
>   [ 1.  1.  4.  1.  4.  4.  1.  1.  4.  0.  9.  4.  9.  4.]
>   [ 1.  4.  1.  4.  1.  1.  9.  9.  4.  9.  0.  4.  1.  4.]
>   [ 1.  9.  4.  1.  9.  1.  1.  4.  4.  4.  4.  0.  4.  1.]
>   [ 1.  4.  1.  4.  4.  4.  9.  4.  4.  9.  1.  4.  0.  1.]
>   [ 1.  9.  4.  1.  9.  1.  4.  1.  9.  4.  4.  1.  1.  0.]]
>
> For this matrix, I'm getting this with numpy:
>
>   2774532095.9999971
>
> But I have a feeling I'm exceeding the capacity of floats here. Does
> anyone have an idea for how to treat this? Is it absurd to think I  
> could
> get a determinant of this matrix? Is there a python package that could
> help me?
>
> Many thanks for any answers.
>
> James
> -- 
> http://mail.python.org/mailman/listinfo/python-list
	Are you sure NumPy return float results. As far as I know, it  
returns doubles
(about 16 digits)
------------------------------------------------------
"Home is not where you are born, but where your heart finds peace" -
Tommy Nordgren, "The dying old crone"
tommy.nordgren at comhem.se