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Extension of MatrixExp



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


In[3] = matrixExp[m_ , t_] := Module[

        {e,d,i,j} ,

        e = m // N // Eigenvectors // Transpose ;

        i = e // Inverse ;

        d = i.m.e ;

        d = d*t ;

        Do[ d[[j,j]] = Exp[d[[j,j]]] , {j, Length[d]}]

        e.d.i

        ]


In[4] = matrixExp[m , t]

The result is ok, but perhaps somebody have a best (more compact)
solution...


Thank you for your answers.

Fred lang




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