# Tagged Questions

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### Integration of ODE equation in Matlab / Octave

I have a system of 8 ODE's where the initial conditions are in matrix form. $\frac{dT}{dS} = H T$ where T at the initial state is the identity matrix. $T(a) = I$ H is a constant 8x8 matrix T is ...
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### Fast algorithm for approximating Eigenvalue distribution of large sparse matrix

I am interested in the eigenvalue distribution of a huge $2^{16}$x$2^{16}$ Hermitian sparse matrix with spectrum contained in $[-1,1]$. That is I don't need to know all eigenvalues exactly, but rather ...
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### Gauss Seidel iteration in matlab

I've posted this question before for crout factorization. Now, I need help with Gauss-Seidel iteration. Write a program that takes a value for n and solves for x using the following method: ...
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### Matlab terminate code if warning occurs [closed]

I am running a code where by I want to maximise a parameter (basically the range of integration) by increasing it in steps until a warning occurs. It involves inverting a linear system Ax=b and I want ...
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### Dense symmetric positive definite matrix

How could one define a dense symmetric positive definite matrix (dimension $1000 \times 1000$) with uniformly distributed eigenvalues (with the smallest eigenvalue $1$ and the condition number $100$) ...
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### Solve Ax = b, but I have a function that implements A

I have an overdetermined linear system $Ax = b$. I need to choose an $x$. $x$ has about 100 elements in it. If I had the matrix $A$, I would set x equal $A^\dagger b$, the pseudoinverse of $A$ ...
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### Partial vs. full eigendecomposition when computing matrix logs with Matlab

I'm looking over a program that performs a matrix logarithm in each iteration, which necessitates looking at the eigendecomposition of the given matrix iterate $M^{(i)}$. However, rather than consider ...
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### What is the algorithm for LU factorization in MATLAB?

What is the algorithm for LU factorization in MATLAB, i.e. [L,U] = lu(a)? After searching for many examples and trying to compare the result with MATLAB, they are ...