Questions tagged [matlab]

For mathematical questions about MATLAB; questions purely about the language, syntax, or runtime errors would likely be better received on Stack Overflow. MATLAB is a high-level language and interactive programming environment for numerical computation and visualization developed by MathWorks.

2,600 questions
27 views

fractional imaginary calculation

Assume $j=\sqrt{-1}$, to calculate $(-3.1416j)^{0.5}$ in Matlab, I type (j*-3.1416)^0.5 and it gives me the result: ...
139 views

Crank-Nicolson code for in-situ combustion model (MATLAB)

I need to solve in MATLAB the following system (1): \begin{align} &\frac{\partial \theta}{\partial t} + u \frac{\partial (\rho\theta)}{\partial x} = \frac{1}{\text{Pe}_T} \frac{\partial^2 \...
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How to simplify exponential matrix complex output in MATLAB?

I want to use MATLAB to find $e^{\mathbf{A}t}$ for $$\mathbf{X'}=\begin{pmatrix} -3 & -1 \\ \phantom{-}2 & -1 \end{pmatrix}\mathbf{X}$$ this is what I wrote in the command window ...
26 views

Plotting basis vectors of a 3D local coordinate system defined by a homogenous transform

Given a 4x4 homogenous transform $H$ I know that the first three columns of $H$ (ignoring the last row) define the basis vectors of the 3D coordinate system that it moves its "parent" coordinate ...
19 views

Estimating probability density function of big amount of data coming from Monte Carlo simulation

I am trying to estimate Probability Density Function (PDF) of a big amount of data ($1e^6$ , $1e^7$, and higher) coming from Mote Carlo (MC) simulation. My objective is to estimate the PDF (e.g. with ...
37 views

Plots in MATLAB

Is it possible to generate by MATLAB, plots and subplots like the ones below? The plots come from an economics paper (http://people.bu.edu/sgilchri/research/GSSZ_FHMU.pdf) and I have looked at ...
63 views

How does MATLAB compute the real Schur decomposition?

Let matrix A be defined as ...
20 views

Fredholm determinant

Suppose we have a Jacobi unitary ensemble $W$ with eigenvalues $-1<\lambda_{1}\leq \lambda_{2}\leq \cdots\leq \lambda_{n}<1$. We can express the eigenvalue correlations near $1$ in terms of the ...
32 views

How to find a non-singular sub-matrix in a full-rank matrix.

Suppose we are given $A\in\mathbb{R}^{n\times m}$, where $n<m$, and we know that $A$ is a full-rank matrix. What is a simple and efficient way to find any submatrix $B\in\mathbb{R}^{n\times n}$ ...
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Want to compute product of Bessel and Hankel function in Matlab - $J_m(x)\cdot H_m^{(1)}(y)$ - but large order or argument returns 'inf'?

I am trying to compute (in Matlab) the product of a Bessel function and a Hankel function where the order $m$ of the functions may be very large and/or the arguments $\alpha x$ and $\alpha y$ of the ...
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BVP with intermediate constraints (Multipoint BVP?)

I have a scalar BVP in the form $$\ddot{n}(t) = f(n(t),\dot{n}(t),t)$$ with BCs $\dot{n}(0) = \dot{n}(t_f)=0$. In addition to these BCs, I have constraints on velocities as $\dot{n}=0$ at ...
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Is there mistake in derivation/simulation of Maximum A Posterori (MAP) estimation?

I'm trying to estimate $X$ using MAP Estimator. If $Y = aX + N$, where $a$ is a constant, $X \sim \mathcal{N}(0,\sigma_{x}^{2})$ and $N \sim \mathcal{N}(0,\sigma_{n}^{2})$. The likelihood function ...
7 views

2D Meshing of an Arbitrary Polygon in Matlab

I am trying to create meshing for an arbitrary polygon; such as, ...
11 views

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Making a animation in Matlab, timedependent function $T\mapsto R_T$

I am dealing with the Pontryagin-Maximum-Principle and i calculated the so called reachable set $R_T$. I am using the following code that plots the reachable set for a certian endtime $T$: ...
62 views