All Questions
Tagged with scoping differential-equations
15 questions
2
votes
2
answers
157
views
Replacement with equivalent local variable and global variables give apparently different results using the same NDSolve output
I am solving a system ODEs which Mathematica quickly gives me a result varsol and dvarsol. Up to this point, everything is good.
...
- 1,495
0
votes
1
answer
275
views
How to use result of NDSolve within a module?
I want to numerically solve a differential equation and use the resulting interpolating function for further calculations:
...
- 197
0
votes
1
answer
69
views
2
votes
1
answer
75
views
How to "Hold" variables assigned value inside DSolve?
Consider the following ODE:
a = 0.8; b = 8;
v = DSolveValue[{
u[x] == a*(b* u'[x] + u''[x]),
u[4.925] == 4,
u'[4.925] == 0.625
}, u[x], x]
which gives ...
- 153
0
votes
0
answers
73
views
NDSolve and NIntegrate with parameters
I have a problem with a numeric computation. I should solve a numeric ODE and the rhs is a numeric parametric function that I find with several NIntegrate. I'd like ...
- 1
1
vote
2
answers
131
views
Problem with internal variable of a `Module` which returns the solution of an `NDSolve` command. y$25947 → InterpilatingFunction[…]
I will try to give a minimal example of my problem. Say I define the following function, spitting out an NDSolve result, using ...
- 683
1
vote
1
answer
111
views
NDSolve with Events that reevaluate with different Discrete Variables
I have the following problem:
I have a set of ODEs and some discrete variables which I can solve successfully. Now I want mathematica to check at every $0.1 \,t$ time step, wether it would increase ...
5
votes
1
answer
131
views
why DSolve in V 12 returned an internal module variables with $ on them in this example?
Fyi, Reported to WRI in case it is a bug. [CASE:4288939]
Is this supposed to happen?
...
- 150k
0
votes
1
answer
216
views
5
votes
2
answers
207
views
HoldAll Attributes and Delayed Evaluation: ContourPlot with solutions to NDSolve
This is a general question on evaluating functions that are defined to be evaluated with delay.
In particular, I am having difficulties working with the ...
- 607
5
votes
2
answers
280
views
Sow in WhenEvent can't extract parameter value of ParametricNDSolve
This is a problem I noticed when trying to answer this question. Just consider the following toy example:
...
- 68.4k
3
votes
2
answers
329
views
Problem with Evaluate inside Module
My problem
I have a large system of differential equations which is automatically created, but to give you an easy example let's just say it is
...
- 379
0
votes
0
answers
144
views
How do I declare global constants and local constants? [duplicate]
Many times I have a Mathematica code like this
...
- 697
5
votes
4
answers
572
views
Memory Problem with Modules and NDSolve
I'm using NDSolve inside a module, and I appear to have a memory leak. The relevant code is:
...
- 560
0
votes
1
answer
155
views
Substitution of a function in a differential equation
Suppose we have a differential equation as follows:
g[t_] := t/2
m[t_] := t/3
A[t_] := {{g[t], 1}, {1, m[t]}}
p'[t] == A[t]. p[t], p[0] == {1, 0}
...
- 25