# All Questions

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416 views

### Rapidly determining whether or not a dense matrix is of low rank

In a software project that I'm working on, certain computations are vastly easier for dense low-rank matrices. Some problem instances involve dense low-rank matrices, but they're given to me in full, ...
34 views

### How to determine the orientation of convex/concave hexahedra?

I am writing a code that checks the orientation of a list of vertices (along with face connectivity) describing both convex and concave hexahedra. The face connectivity table stores the list of vertex ...
54 views

### Solving absolute value systems

Let $z, b \in \mathbb R^n$, $A \in M_n (\mathbb R)$ and $|z| := (|z_1|, \dots, |z_n|)$. I am searching for an efficient algorithm to solve the absolute value system: z - A |z| = b. \...
39 views

### RBF-FD laplacian solver on python

I am trying to find a laplacian of the function explicitly using the RBF-FD approach The function is sin(pi*x)*cos(pi*z/2) and its analytical solution of the ...
18 views

### optimization for complex number

I don't know how to solve the optimization problem. Please suggest a theory or approach to solving the above optimization problem.
31 views

### Efficiency of scipy.sparse.linalg.expm_multiply with sparse vs unsparse vectors

From the package scipy.sparse.linalg in Python, calling expm_multiply(X, v) allows you to compute the vector ...
86 views

49 views

### 2-norm and infinty norm of a system in controls

How to compute 2-norm or infinity norm of following system? i am confused whether to calculate using simple matrix theory "where it don't regard for s domain" or H2 and H-infinty norm. ...