Re: [Maxima-discuss] matrixexp

[Raymond R. <ray...@gm...>]

On 02/20/2014 05:05 PM, Mark wrote:
> On 02/20/2014 05:59 PM, Raymond Rogers wrote:
>> Because of the way matexp is implemented the following produces the
>> wrong result:
>>
>> The following has an incorrect result
>> Two files are attachedon: e source and one window dump generated from
>> the source.
>> H_Lag :
>> matrix([0,0,0,0,0],[-1,1,0,0,0],[-1,0,1,0,0],[-1,0,0,1,0],[-1,0,0,0,1]);
>> P_Lag : matrixexp(H_Lag);
>>
>>                        [   1     0   0   0   0  ]
>>                        [                        ]
>>                        [ 1 - %e  %e  0   0   0  ]
>>                        [                        ]
>> 		        [ 1 - %e  0   %e  0   0  ]
>>                        [                        ]
>>                        [ 1 - %e  0   0   %e  0  ]
>>                        [                        ]
>>                        [ 1 - %e  0   0   0   %e ]
>>
>> Which is certainly wrong

> Are you certain?

i am absolutely certain I made a mistake and apologize for wasting 
peoples time thinking about it!

Embarrassed
Ray
>
> Your matrix H_Lag satisfies H_Lag^^n = H_Lag for any integer n>0. So,
> matrixexp(H_Lag) = identfor(H) + H_Lag*(%e-1)
> which is your P_Lag
>
> -M

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