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• To: mathgroup at smc.vnet.net
• Subject: [mg22576] Question
• From: aranisin at usc.edu (aranisin)
• Date: Sat, 11 Mar 2000 17:52:47 -0500 (EST)
• Organization: University of Southern California, Los Angeles, CA
• Sender: owner-wri-mathgroup at wolfram.com

Hello,

In the following code, the program takes more
runtime and memory resources than that allowed 
by my system.  The suspected code is underlined. 
Is there a better way of writing this code?

Please e-mail me responses at this e-mail address.

Thank you very much.

Arani Sinha


ScientificForm[%];

R11=2;
R22=2;

L11=10^-9;
L22=10^-9;
L12=5 10^-10;

C11=25 10^-15;
C22=25 10^-15;
C12=15 10^-15;

Rs1=50;
Rs2=50;

Cs1=10^-14;
Cs2=10^-14;

a=4.24 10^10;



D1={{0,0,-R11,0},
    {0,0,0,-R22},
    {0,0,0,0},
    {0,0,0,0}};

E1={{0,0,-L11,-L12},
    {0,0,-L12,-L22},
    {-C11,C12,0,0},
    {C12,-C22,0,0}};

X=D1+s E1;
Y=MatrixExp[X];

A={{1/Rs1,0,0,0,1,0,0,0},
   {0,1/Rs2,0,0,0,1,0,0},
   {0,0,s Cs1,0,0,0,-1,0},
   {0,0,0,s Cs2,0,0,0,-1},
   {Y[[1,1]],Y[[1,2]],-1,0,Y[[1,3]],Y[[1,4]],0,0},
   {Y[[2,1]],Y[[2,2]],0,-1,Y[[2,3]],Y[[2,4]],0,0},
   {Y[[3,1]],Y[[3,2]],0,0,Y[[3,3]],Y[[3,4]],-1,0},
   {Y[[4,1]],Y[[4,2]],0,0,Y[[4,3]],Y[[4,4]],0,-1}};

Vs=1/(s+a);
V={{Vs/Rs1},{0},{0},{0},{0},{0},{0},{0}};

M[i_]:=M[i]=D[M[i-1],s];
M[0]=A;
Z[i_]:=Z[i]=(Limit[M[i],s->0,Direction->1])/(Factorial[i]);

P[k_]:=P[k]=-Inverse[Z[0]].(Sum[Z[r].P[(k-r)],{r,1,k}]);
--------------------------------------------------------
P[0]=Inverse[Z[0]].V;
---------------------
Q=P[0]+s P[1]+s^2 P[2]+s^3 P[3]+s^4 P[4]+s^5 P[5];
-------------------------------------------------

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