All Questions
11 questions
1
vote
1
answer
359
views
Fitting delay differential equations (DDE)
I have the following differential equations:
$$S'(t) = 0.31 S(t) \Big( 1 - \frac{S(t)}{6.19} \Big)- \frac{a}{1 + B(t)} S(t),$$
$$B'(t) = c (1 - B(t)) - d B(t) S(t) - 3 c (1 - B(t - 18)),$$
where $B(t -...
user95418
3
votes
1
answer
133
views
1
vote
1
answer
60
views
How to fit a linear ODE system?
Consider the equations
$$
\begin{align}
b'(t)=p_1 c(t)-k_1b(t),\\
c'(t)=p_2b(t)-k_2c(t)
\end{align}
$$
Given data on $b$ and $c$, and initial conditions, how do I find the best fitting parameters $k_1,...
- 4,953
1
vote
0
answers
118
views
Non linear differential equation plot [closed]
Consider the following paper:
https://reader.elsevier.com/reader/sd/pii/S0096300306007715?token=2B98E3B12F1E623C99A0787996469AF36E8EF230F6ED5289EAFB60B64CE79A6ACCF74B946A34F3370C65D4FC99018648&...
- 407
1
vote
2
answers
194
views
FindFit problem, some models work -- and some do not
I asked this question. Answers and comments were appreciated.
But (some) of the comments did not make satisfied. [Maybe due to my bad English I did not describe my problem very well].
Let me try ...
- 338
1
vote
3
answers
232
views
FindFit, FindFormula, Fit, NonlinearModelFit - Which one to use? (I got no good curves & plots)
See this code, what mistake I did? (I got no plot)
...
- 338
3
votes
1
answer
186
views
How to compute "SinglePredictionConfidenceIntervalTable"-Values on validation data with NonlinearModeFit?
When I perform a NonlinearModelfit I get a FittedModel object and I can see the values of the property "SinglePredictionConfidenceIntervalTable".
Now I apply the FittedModel object on a new data case (...
- 119
0
votes
2
answers
206
views
Can NonlinearModelFit be used instead of TimeSeriesModelFit without loss of generality?
I am trying to model sales seasonality. As I am unfamiliar with TimeSeriesModelFit[], I am using NonlinearModelFit[]. However, ...
- 1,605
0
votes
2
answers
286
views
From the data the growth of tumor spheroids determine doubling time using Mathematica and by hand
Task:
From the data the growth of tumor spheroids determine doubling time
Link to the data.
My idea was to use least squares method and Mathematica to helps me find result. But I think that this is ...
- 103
4
votes
2
answers
259
views
Comparison between numerical solution of nonlinear ode and nonlinear ode of second order
Background
Let's consider the following initial value problem for nonlinear system
$$
\begin{cases}
E' &=& 1 - n_e, \\
n_e' &=& -8\,n_e\,E,
\end{cases}
\tag{1}
$$
with the following ...
- 129
2
votes
1
answer
6k
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:
...
- 23