Mathematica 9 is now available
Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
1995
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 1995

[Date Index] [Thread Index] [Author Index]

Search the Archive

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}

--------------------------------------------
 Pasquale Nardone                          *
                                           *
 Universiti Libre de Bruxelles             *
 CP 231, Sciences-Physique                 *
 Bld du Triomphe                           *
 1050 Bruxelles, Belgium                   *
 tel: 650,55,15 fax: 650,57,67 (+32,2)     *
        ,,,
       (o o)
----ooO-(_)-Ooo----


  • Prev by Date: Speedcomparison of Mathematica on Various Machines
  • Next by Date: RE: Re: Re: X-FrontEnd crashes upon certain keystrokes
  • Previous by thread: numerical solutions to matrices??
  • Next by thread: Re: numerical solutions to matrices??