Re: [Maxima-discuss] matrixexp

[Helmut J. <jar...@ig...>]

On 03/19/2014 10:08:12 AM, Iai Masafumi ax wrote:
> Hi,
> 
> Could you tell me the meaning of this warning message from  
> matrixexp()?
> 
>  "Proviso: assuming 4*(w3^2+w2^2+w1^2) # 0"
> 
> Can I consider its result is reliable?
> 
> The commands I entered are below:
> 
> declare(w1, real);
> declare(w2, real);
> declare(w3, real);
> W:matrix([0, w3, -w2, w1], [-w3, 0, w1, w2], [w2, -w1, 0, w3], [-w1,
> -w2, -w3, 0]);
> expW:matrixexp(W);
> 
> 
factor(determinant(W));
gives (w3^2+w2^2+w1^2)^2, so Maxima assumes that W is a regular matrix.
I don't know the internals of matrixexp, but the warning states that the
result is OK unless W is singular.

Helmut