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Re: numerical solutions to matrices??

  • Subject: [mg2763] Re: numerical solutions to matrices??
  • From: pnardon at ulb.ac.be (Pasquale Nardone)
  • Date: Thu, 14 Dec 1995 01:46:50 -0500
  • Approved: usenet@wri.com
  • Distribution: local
  • Newsgroups: wri.mathgroup
  • Organization: Université Libre de Bruxelles

the solution is (if A is t-independant):
phi[t]=Exp[A (t-t0)]. phi[t0]

so you can use MatrixExp[A (t-t0)] to see your solution
for example:
In[17]:=
A=Table[Random[Real,{0,1}],{18*18}];
In[18]:=
A=Partition[A,18];
In[19]:=
m[t_]:=MatrixExp[A t]
In[20]:=
m[1].Table[Random[Real,{0,1}],{18}]
Out[21]=
{3481.83, 3862.08, 4212.43, 4398.74, 3460.61, 3715.79, 3763.28, 
3059.84, 3439.42, 4540.72, 3938.2, 3422.45, 3910.71, 
3144.03, 3479.06, 3443.73, 3884.24, 3297.41}

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