% A truss example
% The unknowns are F1, ..., F7, R1, R2, R3
a = cosd(30);
b = cosd(60);

A = [b, -b,  0,  0,  0,  0, -1,  0,  0,  0;
     a,  a,  0,  0,  0,  0,  0,  0,  0,  0;
     0,  0,  0,  b, -b,  0,  1,  0,  0,  0;
     0,  0,  0,  a,  a,  0,  0,  0,  0,  0;
    -b,  0, -1,  0,  0,  0,  0,  1,  0,  0;
     a,  0,  0,  0,  0,  0,  0,  0,  1,  0;
     0,  b,  1, -b,  0, -1,  0,  0,  0,  0;
     0,  a,  0,  a,  0,  0,  0,  0,  0,  0;
     0,  0,  0,  0,  b,  1,  0,  0,  0,  0;
     0,  0,  0,  0,  a,  0,  0,  0,  0,  1 ]
     
rhs1 = [0,  0,  0,  0,  0,  0,  0,  1000,  0,  0]'
rhs2 = [0,  0,  0,  0,  0,  0,  0,  1050,  0,  0]'

A \ rhs1
A \ rhs2

% Here the gaussian elimination step is done once

[Aupper,r] = gauss(A)
gaussSolve(Aupper, r, rhs1)
gaussSolve(Aupper, r, rhs2)