Re: Extension of MatrixExp
- To: mathgroup@smc.vnet.net
- Subject: [mg11723] Re: [mg11669] Extension of MatrixExp
- From: David Withoff <withoff@wolfram.com>
- Date: Thu, 26 Mar 1998 03:08:51 -0500
> Dear MathGroup users,
>
> MatrixExp is not able to give me a nice answer in the following very
> easy case:
>
> In[1] = m = {{2,0,0},{0,3,0},{0,0,4}} ; (* A diagonal matrix *)
>
> In[2] = MatrixExp[t*m]
>
> I define my own function
>
> The result is ok, but perhaps somebody have a best (more compact)
> solution...
>
> Thank you for your answers.
>
> Fred lang
Try using ToRadicals:
In[1]:= m = {{2,0,0},{0,3,0},{0,0,4}} ;
In[2]:= MatrixExp[t m] //ToRadicals
2 t 3 t 4 t Out[2]= {{E , 0, 0},
{0, E , 0}, {0, 0, E }}
The fact that you need to do this is an oversight in Version 3.0. This
will almost certainly be changed for the next release of Mathematica.
Dave Withoff
Wolfram Research