# All Questions

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124 views

### Initial values of position (x) and speed (v) of a particle visualizing using Mathematica

$$\vec{F}(\vec{r})=-m\omega^2\begin{pmatrix}x\\4y\end{pmatrix}$$ I have the force $F$ shown above. How could I specify the initial values of position ($x$) and speed ($v$) in Mathematica using the <...
254 views

### Solving Differential Equation System for HIV Treatment Model

I was working on a project about optimal strategies for HIV treatment, models used from [Butler, Kirschner, and Lenhart] 1997. This model explains the spread of HIV viruses in the human body, where ...
228 views

### How to directly input calculated Geodesic differential equation into *NDSolve*

I am trying to find the trajectory of a test particle around a relativistic object. Initially, I was trying the Kerr metric as spacetime but the final simulations clearly were not correct as I saw the ...
66 views

332 views

### Calculating the current through coil with a flyback diode using NDSolve

I plan to simulate the current through a coil with flyback (or freewheel) diode for an arbitrary voltage signal (square or PWM modulated signal is possible). You can find the circuit diagram over ...
105 views

### How to avoid unnecessary calculations in a numerical simulation and improve performance? [closed]

Corresponding to the previous question I posted: Discontinuous boundary condition distorts in the numeric solution. ...
103 views

### How to define inclusions in FEM/NDSolve? [closed]

I am trying to simulate the compaction process of hot mix asphalts and want to do this with mathematica's FEM libraries. How can I define inclusions in meshes (i.e aggregate particles in the binder) ...
209 views

### Issues with modeling pulses in a very simple system of DAEs

Bug introduced in 10.4.1 or earlier and fixed in 11.0.0 Bug has been confirmed by WRI [Case:3594387]: It does appear that the NDSolve function is not behaving properly in this case and an incident ...
478 views

### Beam deformation due to localized force distribution

I would like to simulate the deformation of a beam which is fixed on one end and has some localized forces applied along the top. I have been inspired by this Mathematica example: http://www....
523 views

### Solving coupled first-order autonomous differential equations

I am trying to run a simulation of a circuit to observe chaotic behavior, and have obtained a set of differential equations from an analysis of the circuit. I thought perhaps I could produce a plot ...
893 views

### Evaluation problems with NDSolve using the fixed step ExplicitEuler-Method

Motivation I am using Mathematica to implement System Dynamics (SD) models, e.g. differential equation models as applied to management/economic problems following the "methodology" of Jay W. ...
127 views

### My simulation is not never finishing and it is taking so much time?

I am running simple code which involves calculation of two first order differential equations.It is taking so much time and i am unable to get the results as the simulation is never finishing. ...
386 views

### Simulate a polygon bouncing with collision detection inside a circle/polygon

Simulate a polygon bouncing with collision detection inside a circle/polygon. the example can be see in help page by searching WhenEvent; ...
158 views

### How to control pedestrians to enter the simulation region with random functions?

I am working on simulating crowds of a cross-typed region, given that pedestrians entering from 4 gates of north, east, west and south, ...
623 views

### Optimizing Monte Carlo simulation of a Pred-Prey model

My assignment and code As part of an assignment for one of my classes, I'm trying to run a "massive" Monte Carlo simulation in Parallel on the follow model: ...
632 views

### Partial Differential Equation in Parallel

is there any native way to implement multi-core parallel solving of PDE in Wolfram Mathematica? WM 10 now supports Finite Elements Method, but it is actually useless without parallelization. Usually ...
7k views

### Animation of double pendulum

Sadly, I am a completely newbie. I am studying Physics and in our theoretical physics class we got the task to solve the double pendulum using Mathematica. We just got the program, but no introduction ...
560 views

### NDSolve with arrays and Tables of Equations and WhenEvent

I've been toying around with NDSolve for a while, and read through the website. By doing so I discovered that I could use it for vectors and arrays with much pleasure. So I wanted to write a simple ...
1k views

### Detecting a collision in n-body simulation with NDSolve

Consider this three-body system: ...
900 views

### Problem using WhenEvent to constrain solution

Note: This question has also been posted at the Wolfram Community Problem: Simulate pressure in volume 1 and 2 for 1 second. The circuit is as follows: From this I set up the governing DE for both ...