# Tagged Questions

Questions on the symbolic (DSolve, DifferentialRoot) and numerical (NDSolve) solutions of differential equations in Mathematica.

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### Any possible to save a 'partial' result of NDSolve when it was aborted due to insufficient memory?

I have run a NDSolve code for an extremely long time. Unfortunately, it was aborted because there was insufficient memory available to complete the computation. At ...
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### How to pass arguments in NIntegrate and NDSolve

I am solving PDEs with NDSolve and NIntegrate, but I do not know how to pass arguments correctly. My orignial code is very ...
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### Plotting Limit Cycle

I have Lotka Volterra Equations where the prey equation is modified. The Equations are x'[t]=a*x[t]*(1-x[t]/k)-b*x[t]*y[t] y'[t]=-c*y[t]+d*x[t]*y[t] To plot the ...
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### Numerical fitting trajectory to model that has NDSolve

I have a model which describes the motion of an object on a plane. ...
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### Double Integral with NDSolve!

I have fivefold multiple integral and I wanted a speed calculations.I came across on this Question and had already begun the problems. Here is a toy example with simple double integral: ...
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### Fitting Three-Dimensional Data with Parameters

I have been trying to fit a model of rate equations to data of three dimensions. The rate equations in my model are as follows. ...
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### In NDSolve, how to involve in the odes a integration function that depends on ode functions and can't be analytically integrated?

I think it would be better to use this simple code to explain my questions: ...
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### PolarPlot with InterpolatingFunction not working?

So I have solved a PDE with NDSolve which returns h -> InterpolatingFunction. I can happily plot the results with ...
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### Diffusional equation [closed]

I am still new to Mathematica. I'm trying to solve a diffusional equation ...
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### Can I solve system of differential equation in a matrix form?

I'd like to solve simple system of differential equations: x'[t] == 6x[t] - 6y[t], y'[t] == x[t]-2y[t]; but I want to avoid formulas like DSolve[{x'[t] == 6x[t] - 4y[t], y'[t] == x[t]-2y[t]}, {x,y},...
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### Working with Real/Imaginary/Modulus parts of an complex Interpolating Function?

From solving n times a numerical (complex) equation, like: ...
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### How do I get a 'list' (or something similar) of functions?

I'm solving an NDSolve equation, like: ...
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### How many boundary conditions are required for two coupled Non-linear ODE in two variables?

I'm using NDSolve to solve the following two coupled Nonlinear ODEs in two variables: Equation1 = Equation2 = It can be seen that the level of nonlinearity is very high. I have solved the ...
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### Produce several file outputs within one calculation

I have a differential equation which I solve with NDSolve. With the obtained solution I calculate some quantity. Then a constant in the ODE will be raised (until a ...
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### Looking under the hood of DSolve [closed]

Is it possible to print out information about the algorithms DSolve uses to solve a differential equation? I'm looking for something similiar to this Maple procedure. It lets you specify how much ...
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### Using loops to draw multiple polygons and discretizing them

I am trying to plot the first eigenvalue of the Laplacian operator with zero Dirichlet condition on following figure against decreasing values of $\varepsilon$. I used ...
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### Lagrangian for Spring-Pendulum [closed]

I solved a Spring-Pendulum System with NDSolve. I tried to plot a graph with the interpolated data but always returns a message "An improperly formatted directive with head Symbol was encountered." <...
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### PDE: Specify AccuracyGoal, StepSize, and WorkingPrecision interval-wise [closed]

I am using Mathematica 8. I have two ODEs (in time) and a diffusion PDE (in radius and time) which are all coupled to each other. I solve them using NDSolve by ...
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### numerical values for the solution of NDEigensystem

I tried to solve Schrödinger equation in 3D box using the NDEigensystem. My code is: ...
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### Power Spectral Density Plotting [closed]

I am new to signal processing.I am analyzing the connection between the behavior of the Rossler model and its parameter c. \begin{array}{ll} \dot{x} = -y - z \\ \dot{y} = x + 0.2y \\ \label{eq:...
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### Stiff second order ODE

I am trying to solve numericaly $f''=f^{3}-f$, exact solution is Tanh(x). Problem is numerical solution fails if i coming closer to tanh plateau. StiffnessSwitching method dont help. ...
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### Nonlinear Markov chain (numerical simulation)

Suppose you have a linear Markov process, and you can write it as x(t+1) = Ax(t). Here x is the vector of values, and A is the transition matrix. Since this is linear, it can be solved analytically, ...