Re: Help with Matrices in Mathematica

• To: mathgroup at smc.vnet.net
• Subject: [mg21211] Re: [mg21054] Help with Matrices in Mathematica
• From: "Hans Michel" <hmichel at meddevel.com>
• Date: Fri, 17 Dec 1999 01:29:10 -0500 (EST)
• Sender: owner-wri-mathgroup at wolfram.com

```On Dec 12 arani wrote

Hi,

I am trying to build a matrix of matrices
and wondering whether the following does

Thanks,

Arani

ScientificForm[%];

R11=20
R22=20
L11=10^-8
L22=10^-8
L12=5 10^-9
C11=25 10^-14
C22=25 10^-14
C12=15 10^-14
Rs1=50
Rs2=50
Cs1=10^-14
Cs2=10^-14

Table[Table[f[p,q],{p,4},{q,4}],{i,6},{j,20}]

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}}
One={{1,1,1,1},{1,1,1,1},{1,1,1,1},{1,1,1,1}}
Mat[[1,1]] = One
Mat[[1,2]] = D1
For[i=3, i< 20, i++,Mat[[1,i]]=0]
Mat[[2,1]] = E1
Mat[[3,1]] = (1/2) E1.E1
Mat[[4,1]] = (1/6) E1.E1.E1
Mat[[5,1]] = (1/24) E1.E1.E1.E1
Mat[[6,1]] = (1/120) E1.E1.E1.E1.E1
Do[Mat[[i,j]] = (1/(i+j))*(D1.Mat[[i,j-1]] +
E1.Mat[[i-1,j]]),{i,2,6,1},{j,2,20,1}]

although this is a complicated way of doing things what you are missing is
an array defined for Mat
Mat = Array[m, {6, 20}];

Try the following modification to your code:
I added semicolons and also added the array definition see the asterisk
(remove it if
R11=20; R22=20; L11=10^-8; L22=10^-8; L12=5 10^-9; C11=25 10^-14; C22=25
10^-14; C12=15 10^-14; Rs1=50; Rs2=50; Cs1=10^-14; Cs2=10^-14;
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}};
One={{1,1,1,1},{1,1,1,1},{1,1,1,1},{1,1,1,1}};
Mat = Array[m, {6, 20}];*
Mat[[1,1]] = One;
Mat[[1,2]] = D1;
For[i=3, i< 20, i++,Mat[[1,i]]=0];
Mat[[2,1]] = E1;
Mat[[3,1]] = (1/2) E1.E1;
Mat[[4,1]] = (1/6) E1.E1.E1;
Mat[[5,1]] = (1/24) E1.E1.E1.E1;
Mat[[6,1]] = (1/120) E1.E1.E1.E1.E1;
Do[Mat[[i,j]] = (1/(i+j))*(D1.Mat[[i,j-1]] +
E1.Mat[[i-1,j]]),{i,2,6,1},{j,2,20,1}];
Mat[[3,1]]

I get {{1.62499999999999982`*^-21, 1.37499999999999977`*^-21, 0, 0},
{1.37499999999999977`*^-21, 1.62499999999999982`*^-21, 0, 0}, {0, 0,
1.62499999999999982`*^-21, 1.37499999999999977`*^-21}, {0, 0,
1.37499999999999977`*^-21, 1.62499999999999982`*^-21}}

I would strongly recommend checking out
<< LinearAlgebra`MatrixManipulation`; there might be a more elegant way to
solve your problem paticularly with BlockMatrix

Good Luck

```

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