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May
20
comment Save a C compiled function without losing the blessing of C compiler
@OleksandrR. Er…are you sure? I just tested the code in this answer, and funcNew apparently makes use of the DLL even if I restart Mathematica: i.stack.imgur.com/gIqig.png
May
19
comment Can Mathematica be used for developing “normal” stand-alone software?
Related: mathematica.stackexchange.com/q/37888/1871
May
19
comment Laplace transform of $\frac{1-\cos (t)}{t}$
Well, are you sure that LaplaceTransform[f[t], t, 2 s] is always equal to LaplaceTransform[f[t/2], t, s]?
May
16
comment Analogue for Maple's dchange - change of variables in differential expressions
How about adding one more syntax dChange[expresion, rule, {oldVars}, {newVars}, {functions}] that will internally make use of CoordinateTransform instead of Solve? Then one can do something like Assuming[{r > 0, -Pi < θ < Pi}, dChange[D[f[x, y], x, x] + D[f[x, y], y, y] == 0, "Cartesian" -> "Polar", {x, y}, {r, θ}, f[x, y]]]
May
13
comment Manipulating a damped oscillator plot - plot does not show
possible duplicate of Manipulate not showing anything
May
13
comment Bilateral Laplace Transform
@Guesswhoitis. Yeah, I know, but InverseFourierTransform doesn't know 囧:i.stack.imgur.com/PGcPh.png
May
12
comment Bilateral Laplace Transform
@jlperla I managed to make a better implementation of bilateral Laplace transform, it can handle DE now, have a look!
May
9
comment Save a C compiled function without losing the blessing of C compiler
Actually there's no need to use LibraryFunctionLoad, the only necessary part is to save the DLL to a non-temporary directory. Then one can save & load f2 and recover the C compiled function with something like f2new = ReplacePart[f2, {-1,1} -> (* The file path of the DLL *)]. In this way the RuntimeAttributes of the compiled function will also be recovered so your answer will be fully apply to this question :D
May
9
comment Save a C compiled function without losing the blessing of C compiler
+1. BTW it's a little surprising to me that the default Directory[] isn't included in $LibraryPath.
May
7
comment How to implement symbolic Ramanujan's summation in Mathematica?
@Anixx Yeah, the ability of Sum seems to become the new threshold. BTW the new formula using DifferenceDelta is even harder to implement… p.s. I suggest you to add these formulas to the question rather than in the comment only.
May
7
comment Speed up the auxiliary function magicSquare when $n$ is doubly-even
@ShutaoTang It's undocumented, but mentioned in a few posts here, for example this. You can have a search for more…Well, I admit I found no detailed explanation for so long. Maybe you can consider asking a separate question for this issue?
May
7
comment How to implement symbolic Ramanujan's summation in Mathematica?
@Anixx Seems to be another invalid definition: f[x_] = x; g[x_] = DifferenceDelta[f[x], x]; -NSum[ BernoulliB[Floor@n, 1]/n! Derivative[n - 1][g][0], {n, Infinity}] produces -0.5.
May
7
comment How to implement symbolic Ramanujan's summation in Mathematica?
Well, actually I really tried to solve this problem for a while on the day you raised this question, but finally be confused and worn out by the definition in the wikipedia page. There seems to be several different definitions in wiki, and none of them produces the desired result, maybe I didn't understand them correctly...
May
7
comment How to implement symbolic Ramanujan's summation in Mathematica?
@Anixx What's the definition of $\Delta[]$?
May
7
comment Speed up the auxiliary function magicSquare when $n$ is doubly-even
@ShutaoTang I've added some brief explanation, hope it helps.
May
6
comment Speed up the auxiliary function magicSquare when $n$ is doubly-even
Where's the definition of magic1? By the way Tr@Transpose@mat should be something like Tr@Reverse@mat.
May
6
comment Can we abuse notation and write equations in differential one-form?
I think you really uncovered a blind spot! Now the procedure seems to be evident: Dt[y[x]] evaluates to y'[x] Dt[x] and for any correct DE Dt[x] will be eliminated finally. But these thoughts never came to me!
May
6
comment Singularity or stiffness error solving a system of differential equations
Maybe that's just the nature of your model?
May
6
comment Why does DSolve not give the expected analytical solution for a system of DAE?
I'm not an expert of DAE, but I think for a linear system it's natural to have only one solution. Can you provide a proof for your belief?
May
5
comment Problem solving a nonlinear partial differential diffusion equation
v10 manages to handle bc[[1]] and bc2[[1]]? I think they're redundant, actually they cause failures of NDSolve in v9.