2
votes
0answers
51 views

Locate Blow-up in NDSolve with Whenevent

At some point I get this error: ...
3
votes
0answers
141 views

Numerically solving a system of PDEs where one function is composed with the other

I'm trying to solve the following system using NDSolve: $$ \begin{align} u_t(x,t) &= u_{xx}(x,t) - v(x,t) \\ v_t(x,t) &= u(v(x,t),t) \end{align} $$ with ...
0
votes
1answer
95 views

Problem evaluating results of DSolve (Power::infy)

So, after browsing through older posts to see if anybody else could have had the same problem, I have come to the conclusion that I am stuck. That bothers me, especially because it should be straight ...
1
vote
1answer
76 views
3
votes
3answers
252 views

StreamPlot using NDSolve gives error messages

StreamPlot[{x[0], x'[0]} /. NDSolve[{x''[t] == 1, x'[0] == v0, x[0] == x0}, {x, x'}, {t, 0, 1}], {x0, -2, 2}, {v0, -2, 2}] The above code gives me the errors ...
7
votes
2answers
238 views

Adding a constant vector to a vector differential equation seems to break NDSolve. Why?

I'm trying to solve a differential equation that's phrased in terms of matrices and vectors. My minimum working example is this: ...
1
vote
1answer
279 views

What does the Error Message in DSolve really mean?

Having this ordinary non linear differential equation $$y'-x^2 (y+1)\cdot (y+2)^2= 0$$ with the boundary condition $y(4)=2$. When trying to solve this one with Mathematica by using ...
2
votes
1answer
311 views

Infinite Expression Error from NDSolve

I am trying to solve a differential equation numerically. So I have ...
3
votes
2answers
199 views

How can I get WhenEvent to recognize criterion I specify?

Using NDSolve I want to solve a differential equation till a quantity which is a function of the dependent variables reaches a certain value. My functions and criteria are complicated, but I am able ...
4
votes
1answer
327 views
2
votes
2answers
460 views

Problem with NDsolve for a system of equations

I want to solve a system of differential equations which is not very complicated, but I cannot handle the problem with mathematica!! Please have a look at the problem and result and help me with your ...
3
votes
2answers
355 views

How to set the initial condition? (to make IC and BC consistent)

I want to find the initial condition which fits mixed boundary condition of Phi[r, Theta, t]. The original initial condition in text is Phi[r, Theta, 0] == 1 . ...
2
votes
1answer
381 views

Inconsistent initial and boundary conditions

I have a 4th order nonlinear PDE with the following BCs and IC: ...
6
votes
1answer
291 views

What does MaxStepFraction do?

I find that with NDSolve[...] while solving a partial differential equation, changing the MaxStepFraction from ...