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3h
comment Error propagation code
@DineshKumar Glad it helps. If you feel satisfied with my answer, you can vote it up by clicking the gray triangles and accept it by clicking the checkmark sign.
4h
comment Declaring functions in NDSolve?
Possible duplicate of Simple problem with Manipulate and Plot
5h
comment NDSolve::ivar error when trying to solve DE
Clear[t], NSolve should be NDSolve
6h
comment How to handle a special Neumann-like boundary condition in NDSolve?
@LCFactorization ?NumericQ is necessary to suppress the warning, if you don't mind the warning, simply use solL[xl_]. There're many examples for the usage of ?NumericQ in this site, you can have a search.
6h
comment How to handle a special Neumann-like boundary condition in NDSolve?
@LCFactorization It's just derivative symbol, when xL gets a numeric value, solL[xl] will evaluate to a InterpolatingFunction. As to the reading material part, have you ever read Leonid Shifrin's excellent book? Here's the unfinished Chinese edition: tieba.baidu.com/p/3230448463
17h
comment How to handle a special Neumann-like boundary condition in NDSolve?
@LCFactorization See my edit. If you still have difficulty in understanding, evaluate solL[14] alone and check the output. Notice that precisely speaking, $x_0$ is not undetermined, but to be determined.
19h
comment How to handle a special Neumann-like boundary condition in NDSolve?
@LCFactorization f is just a function that creates function. I create this function for conciseness. These 2 lines can be replaced by sol1[x0_?NumericQ] := NDSolveValue[{eqn, bcl, bcr[[1]]}, y, {x, -14, 0}]; sol2[x0_?NumericQ] := NDSolveValue[{eqn, bcl, bcr[[2]]}, y, {x, -14, 0}];, now it's a little easier to understand, right?
2d
comment NDSolve: problem due to boundary conditions
Just tried ep=zb=10^-4, though some warning pops up, the "shape" of result looks quite similar to that with ep=zb=10^-2, what's the unexpected part?: i.stack.imgur.com/aw0xw.png
2d
comment Differential equations with rational functions as solution
Write the solution out in terms of unknown coefficients, substitute, expand and collect terms, and solve the resulting system of equations is the only approach I can think out, and I think it should work when the degree isn't too high. Can you show an example that is hard to handle with this approach?
2d
comment NDSolve: problem due to boundary conditions
Can you show a concrete example for the numerical errors? Have you tried a higher WorkingPrecision?
2d
comment Partial differential equation with infinity limit
Is it - D[U0[t], t] or + D[U0[t], t]? And where's the initial condition ($u(y,0)=?$)?
Feb
10
comment Can't clear variables with subscripts
Related: mathematica.stackexchange.com/a/46239/1871
Feb
9
comment Table with List iterator return unpacked list
Interesting, another possible evidence: With[{xx = Range[1., 10., 0.01]}, Table[w + ky, {w, Range[1., 10., 0.01]}, {ky, xx}]] // Developer`PackedArrayQ
Feb
9
comment Table with List iterator return unpacked list
Mathematica never promised to give you a packed array :D, anyway, it's a interesting observation.
Feb
8
comment How to define a complicated function inside the body of Compile?
@MichaelE2 Yeah, actually the memory cost is the only thing in my mind, because I think that's what OP is concerned. However, after checking FullForm@f, I noticed my answer is incorrect, it also inserts 3 copies of the (compiled) function into the body! So far I can't think out a way to define a sub routine as OP desires…
Feb
7
comment How to define a complicated function inside the body of Compile?
@MichaelE2 I guess it… depends on how the big nasty function is defined :D
Feb
7
comment Weird behaviour for a vector InterpolatingFunction inside an NDSolve
@march is right, {0} + g[x] will evaluate to {g[x]} before NDSolve execute. I think you'll find this post interesting: mathematica.stackexchange.com/a/97006/1871
Feb
7
comment How to define a complicated function inside the body of Compile?
I think this has little difference with define bigNastyFunction outside and use option "InlineExternalDefinitions" -> True, because then three copies of that function will be inserted into the body of the compiled function verbatim"
Feb
1
comment Problems when solving a nonlinear PDE system with NDSolve
"Is there any offline version of such conversion tools", check this post:mathematica.stackexchange.com/q/1137/1871 . As to your new update, since I'm now at home and have no access to the new mentioned article, I'd like to stop verifying the model, I write this comment mainly to mention, the NDSolve::bcart: can be suppressed by using T[x, 0] == (Tw - Tgin) (Exp[1000 (x - xr)]) + Tgin instead of the corresponding boundary, NDSolve::pdord can be suppressed by using neweq5 = D[sys[[5]], t] /. Solve[D[sys[[4]], t], Derivative[0, 2][Tg][x, t]][[1]]; instead of eq5.
Jan
30
comment Problems when solving a nonlinear PDE system with NDSolve
BTW, I usually use steampiano.net/msc to convert the special characters. halirutan's extension is quite unstable at least in my Chrome.