% Four loops, electE00.m, Spring 04
clear                       % variables
format short e              % E format
volt1 = 8
volt4 = 10
volt5 = 0

k12 = 1/7;  k23 = 1/7;
k34 = 1/11; k24 = 1/12;
k25 = 1/7;  k35 = 1/6;
k11 = k12;
k22 = k12 + k23 + k24 + k25;
k33 = k23 + k34 + k35;
k44 = k34 + k24;
k55 = k35 + k25;
beta = k12*1e7;              % zienk factor

stiff = [ k11   -k12    0      0    0     % matrix
         -k12    k22  -k23   -k24 -k25
          0     -k23   k33   -k34 -k35
          0     -k24  -k34    k44   0
          0     -k25  -k35      0  k55 ];
df =  [ volt1*beta;  0; 0;  volt4*beta; volt5*beta ] 
zienk = stiff;
zienk(1,1)=zienk(1,1)+beta;
zienk(4,4)=zienk(4,4)+beta;
zienk(5,5)=zienk(5,5)+beta

displ = inv(zienk) * df;    % displacements
format short
volts = displ'
current = (stiff * displ)'  % force vector
% print the results
fprintf('\n     Elect04 5x5 ')
fprintf('\n  Your name,  MENG 421, ')
disp(date)

fprintf('\n   Node     Volts     Current\n')
for i = 1:length(df)
  disp(sprintf('    %2.0f   %8.2f   %8.2f',i,volts(i),current(i)))
end

%      Elect04 5x5 
%   Your name,  MENG 421, 12-Apr-2004

%    Node     Volts     Current
%      1       8.00       0.43
%      2       4.99      -0.00
%      3       4.05       0.00
%      4      10.00       0.96
%      5       0.00      -1.39