# Tagged Questions

Questions about approaches for simulating physical systems or phenomena by building from related understanding and basic principles.

134 views

### Sound synthesizer using Manipulate

Sound synthesizers, both digital and analog, often include a parameter section for shaping the amplitude of a sound wave over time. This parameter section is commonly known as an "ADSR EG" (attack, ...
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### Maximum Likelihood Approach for parameter estimation of multi response data, could you provide a tutorial? [migrated]

I was trying to fit the parameters a time dependent system coupled of ODES relate to a kinetic experiment with multi response data. example: A->B+H A+H->C+H A->D dcA(t)/dt=-k1Ca(t)-k2Ca(t)*Ch(t)-k3*Ca(...
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### Multivariable non-linear fitting

I have a function called "C" that I know it depends on 6 variable. I have a set of data points, 6 rows by 9 columns, in which in each row only one variable is changing and the rest of the variables ...
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### FindFit and NMinimize to fit a parametric model (minimize the distance of two curves)

I am trying to find a fit to the cumulative distribution of a set of points using FindFit or NMinimize. In particular, I would like to find the parameters of the cdf of the Beta Distribution that ...
68 views

### Help needed, building a trajectory model [duplicate]

I'm trying to build a trajectory model that considers air-friction. The first step, I reckon is to find the Function of both vertical and horizontal displacement with time, then I can use ...
155 views

### How to simulate Multifractional Brownian Motion?

The maximum I would ask, is hints, how to model MFBMotion. Link to paper Firstly, i wanted to simulate in MATLAB that code: ...
51 views

### Can I model the general political landscape with mathematica? [closed]

I want to develop a website which would model a province of 2 million people from a political point of view. Is mathematica a good fit for such a project? My background is that I'm an experienced ...
204 views

### Problem exporting and re-importing STL file

I wrote all code and there're no errors in code. Result of code is like first picture(left). But I can't Import that structure. The result of import stl file is second one(right one). How can I import ...
113 views

### Transposition of state space form of a transfer function

How can I transpose the output of state space model in Mathematica? trying the following code would transpose the top right symbol s instead of the matrices. ...
114 views

### Extract Transfer Matrix from TransferFunctionModel

I have a MIMO transfer function model, and I'd like to know how to perform arithmetic on this model. For instance, to see the difference between two systems' outputs for arbitrary inputs, I'd like to ...
266 views

### Solution to heat equation with Neumann boundary conditions and lateral heat loss

I am conducting an experiment on heat conduction in a copper rod. To do so I am using a thin copper rod with several temperature probes, then I am going to compare the data with a solution to the heat ...
208 views

### Modeling a stellar atmosphere

I'm trying to model a stellar atmosphere using Mathematica. Basically I'm working in a physical and chemical model which combined should give me a profile of the chemical abundance in the atmosphere. ...
171 views

### Animating a 3D shape along path a (2D and 3D) parametric function curve [Update]

I have a 3D object under the action of gravity field.The trajectory of path is a parabola.I would like to animate , as in the example GIF. ...
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### Disease Network Model Using NDSolve

I have a basic disease model using NDSolve: ...
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### How does Mma compute Confidence Intervals?

I am trying to understand how Mma computes the Confidence Intervals after a NonlinearModelFit. Consider the following example: ...
429 views

### Find fit of an experimental PDF

After quite some struggle, I managed to put up a code that is syntaxically correct. The goal is to find the parameters for a gamma distribution that best match experimental data. The data is a set of ...
127 views

### Martingale pricing_Simulation random walk stock price

I need to make an example of a walk of a stock price.I have this data: and i need to resolve this equation: where "W" is a Wiener process [0,Δt]. I need to make a path of 157 steps(date of ...
128 views

### How can I calculate the maximum number of grid layout possibilities?

I am doing some modelling where I am trying to randomly layout some points on a grid. What I know: How big the grid is The number of objects that have to be laid out on the grid, at a point The ...
358 views

### Computing launch parameters for hitting a point in 3D with projectile under influence of wind

The end goal of this problem is to compute functions which describe the launch parameters which are needed to hit a specified goal in 3D in the presence of wind disturbances. This is as far I have ...
997 views

### Fitting a Damped Sine to Data

I have some collected data that should be modeled by a damped oscillation. Here are the data in a list of ordered pairs: ...
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### Plot Plane to Intersect 3D Contour Plot in Mathematica

I have a 3D model of a heart in Mathematica and I'm trying to create a plane so that the open surface (as seen in the image below) is cut off so that the heart can have a solid, level surface. How ...
202 views

### How can I model the volatility, using a GARCH(1,1), of a time series of returns (and plot it) using Mathematica?

I know that if I use this code: tsm = TimeSeriesModelFit[ret, {"GARCH", {1, 1}}]; I can get the parameters using this: ...
507 views

### Modelling the effect of a structure on a “tsunami” (hyperbolic wave equation)

So, the hyperbolic wave equation can be quite easily solved in Mathematica like this: ...
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### Fitting data with inclusion of constraints

How do I find a fit for the dataS (see below) with the constraint that the parameter np is an integer, and that the parameters la+lc = 100. A weak attempt at this is provided below for a specific ...
2k views

### Mathematica Package for Bayesian Networks

Are there any packages that allow the simulation of Bayesian Networks with Mathematica? I found what seemed to be a promising package (Dynamics) on a Brown University URL, http://www.cs.brown.edu/...
223 views

### How to combine objects from different .obj files?

I got a screw .obj model with the head diameter of 2cm, and a board .obj model of 10cmx10cmx4cm in dimension. I would like the ...
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### Parameters in NDSolve for an Accurate Graphical Output — What to Tweak?

Friday Greetings, I'm working on an ODE system as a basic model for cancer treatment: \$\begin{array}{c} \frac{{dN}}{{dt}} = kN\left( {1 - \frac{N}{\alpha }} \right) - \mu CN\\ \frac{{dC}}{{dt}} = ...
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### ToDiscreteTimeModel fails following video

Following the systems-modeling video here at about 15 min, 20 seconds in, the presenter (Bob Sanhedrick, I think) shows a model for an "Asteroids-game"-like 2D spacecraft. The model is trivial: <...
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### Mathematica Implementations of the Random Forest algorithm

Is anyone aware of Mathematica use/implementation of Random Forest algorithm?
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### Determining the total illumination of a polygon

Is it possible to determine the total illumination of a particular polygon with the given light sources? I truly acknowledge that Mathematica is not supposed to do this modeling, but it is what is ...
242 views

### Problem with SARIMA Time Series Model

I'm in the process of becoming familiar with some on the version 10 new functionality. I have two data sets, datasetA and datasetC, of time series data that I would like to make forecasts on. Here is ...
186 views

### Creating an animated graph model based on equations

So I have a graph that looks like this ...
535 views

### Model fitting to noisy data with a custom minimization function

I'm looking into fitting some data with Mathematica. I've got my head around how NonlinearModelFit works (I've been using the Levenberg-Marquardt algorithm for some ...
163 views

### RSolve fails on a two-equation non-linear system

I have a system of just two recurrence equations, I need to solve them and so I use RSolve: ...
440 views

### Approximate minimum degree permutation algorithm in Mathematica

In MATLAB there is a nice implementation of the so called AMD (approximate minimum degree permutation) algorithm named amd (see Online MATLAB Documentation). There is an alternative algorithm called ...