New answers tagged matlab
1
$0.1$ is not exactly representable in double precision arithmetic, and it will be rounded. The double precision representation of $0.1$ is
$\verb|00111111 10111001 10011001 10011001 10011001 10011001 10011001 10011010|,$
which is $0.100000000000000005551115123126$. As you can see, if you compute $h$ by subtracting "$0.1$" from it repeatedly, you ...
0
To make my comments more explicit:
Try with the following code for the DDE function that eliminates P
function dydt = dde(t,y,yd,A)
n = length(A);
dydt = diag(A).*y;
k = 0;
for i = 1:n
for j = (i+1):n
dydt(i) += A(i,j)*yd(j,k);
dydt(j) += A(i,j)*yd(i,k);
k = k+1;
end
end
end
This eliminates the $O(n^3)$ matrix-vector ...
0
Let's take it from the beginning. I was unable to run your code as it must be missing some input, but I see that your input to the differential equations is the current $I$ which you control as a user, and it looks something like this:
You will notice that this input is discontinuous, and thus non-differentiable. Unfortunately matlab does not have any ...
2
The elemental stiffness matrix must be always singular because while deriving it we do not impose any constraints or boundary conditions. Thus inverting the stiffness matrix to solve for displacements/position-vectors/degrees-of-freedom should yield indeterminate results.
0
I think that what you are looking for is a Computer Algebra System (CAS). You could find a list in Wikipedia.
I don't know which one suits your particular interest, although Singular seems to be a good candidate.
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