6
votes
2answers
156 views

Interpolating an Antiderivative

I'd like to be able to make InterpolatingFunctions for antiderivatives of functions that can't be integrated symbolically. However, the following code returns several error messages: ...
3
votes
0answers
47 views

NIntegrate::ncvbr: How should we interpret and handle this error not mentioned in any documentation?

I have some user-defined module describing my integrand which has to be computed numerically (it's much more complicated than this but bear with me): ...
0
votes
0answers
44 views

NDSolve::derarg error: requiring pure function in solving differential equations

I'm trying to numerically solve 2 partial differential equations eq1 and eq2 given the boundary conditions in ...
9
votes
2answers
315 views

Symbolic integration fails while numerical integration succeeds

I am hoping to evaluate the following integral Integrate[((r^3 - 7)^(2/3)*(1 - (r^3 - 7)^(2/3)/r^2))/r^3, {r, 2, Infinity}] but Mathematica informs me that this ...
7
votes
2answers
264 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: ...
0
votes
0answers
38 views

NIntegrate issue to do with unknown types [duplicate]

I have a numerical function zz: zz[s_ ? NumericQ] := so3toE3[Inverse[yn[s]].ND[yn[k], k, s]]; The other functions involved have 2 pages of code defining them so ...
2
votes
1answer
408 views

Infinite Expression Error from NDSolve

I am trying to solve a differential equation numerically. So I have ...
0
votes
1answer
144 views

Error messages when using NInverseFourierTransform

I have two functions that I need to inverse Fourier transform and I was trying to get Mathematica to help me. I tried simply using theInverseFourierTransform ...
2
votes
1answer
134 views

Differences between ParametricPlot3D and NIntegrate

I have a function $f : \mathbb{R} \rightarrow \mathbb{R}^3$ defined in a rather nasty way in mathematica however it's a smooth function and what not. I am interested in $f'[t]$ and when I run it ...
4
votes
1answer
343 views

Differential Equations with Matrices

I'm trying to implement the differential equation of a Cellular Neural Network in Mathematica as seen below: ...
4
votes
1answer
491 views
2
votes
2answers
610 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 ...
0
votes
1answer
2k views

Stategies to avoid NIntegrate::slwcon error

I am trying to numerically evaluate an integral whose integrand depends on two parameters, say $(a,b)$ and when $b\gg 1$ I suspect (although it's not guaranteed) that the integrand is very small. Thus ...
3
votes
2answers
382 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 . ...
5
votes
1answer
2k views

How do I prevent NIntegrate::inumr errors within other functions?

I believe this question is best illustrated with a simple example. If I run FunctionInterpolation[NIntegrate[a + b, {a, 0, 1}], {b, 0, 1}] I get errors of the ...
4
votes
1answer
299 views

Error Interpretation in NIntegrate

I am using a recursion algorithm developed by Migdal for Lattice Field Theory, and I have the following code: ...
6
votes
1answer
342 views

What does MaxStepFraction do?

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