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Feel free to correct the grammar mistakes in my posts.


Nov
5
comment Poisson PDE using FDM in Mathematica
Well, if you don't add @xzczd in your comment, I won't get the reminder. BTW, your new-added code is messy (and in fact broken), please press Ctrl+Shift+I to change it into InputForm before pasting it here.
Nov
5
comment A Stupid Question Maybe - EigenNDSolve
"It may be that floating point numbers should not be input as such", this explanation isn't wrong, and I think the failure will be reproduced in any version of Mathematica. To fix the problem, the easiest way is to change the floating point numbers into exact numbers i.e. change 10.5 etc. to 105/10 etc.
Nov
3
comment Problem with series expansion and integrate
@rhermans Apparently it's not available for OP, one needs at least 75 reputations to start a bounty 囧.
Nov
3
comment Fluid mechanics problem concerning flow over a wedge
If you feel satisfied with an answer, you can click the checkmark sign to accept it.
Nov
1
comment Poisson PDE using FDM in Mathematica
@wlkyr So the polar form isn't what you need either and you simply want to explore FDM for irregular region?
Nov
1
comment Poisson PDE using FDM in Mathematica
Well, is it necessary for you to use FDM rather than NDSolve solving this equation? To say at least, is it necessary for you to use Cartesian form of the equation rather than polar form? The handling for irregular mesh in FDM is really cumbersome in my view, in fact that's where I stoped my self-learning for FDM. (You may be interested in this post. )
Nov
1
comment Division by zero is slow
@wxffles I think the most probable obstacle for one to understand the code is unfamiliarity with Unitize and vectorization :) …OK, I've added a bit explanation, just a bit though.
Nov
1
comment Aligning the axeslabel in a 3D list plot ($x,y,z$) (edited)?
@SeyhmusGüngören Sorry, I can't understand what you mean, I just checked my approach with kguler's data, the behavior is exactly the same at least in my computer. Can you elaborate a little?
Oct
28
comment Aligning the axeslabel in a 3D list plot ($x,y,z$) (edited)?
@AlexeyPopkov Oh, I didn't know this function! Added.
Oct
28
comment Division by zero is slow
The trick will fail when c and d are using different masks. (Block won't help because the FullForm of the output of ComplexInfinity generated by 1/0 etc. is DirectedInfinity[].) Anyway, it's the fastest method for OP's specific example so far.
Oct
28
comment Second order differential equation with boundary conditions solving repeatedly
If you simply want to make the code elegant, have a look at Do, While, Nest, NestWhile etc. Nevertheless, I'm afraid it's hard to speed up the code if you want dd[x] to be analytic. BTW, shouldn't the phi[x] phi[t] be phi[x]^2?
Oct
28
comment Solving Differential Algebraic Equations as BVP
@VenkatKV You can also consider using RootSearch. BTW, you can click the checkmark sign to accept it if satisfied with an answer.
Oct
25
comment Solving Differential Algebraic Equations as BVP
@VenkatKV No, it's just the StandardForm of ==. (Notice its length. ) Which version of Mathematica are you using? What's your platform? I'm using v9.0.1, vista 32bit. You can try narrowing down the scope of FindRoot, for example {slope, 0.1, 0.3} etc.
Oct
24
comment Solving Differential Algebraic Equations as BVP
@VenkatKV Of course: i.stack.imgur.com/wPNna.jpg What do you mean by "ot able to get the result"? The result is wrong, or it doesn't give any result, or something else? BTW, ParametricNDSolve is a v9 function.
Oct
23
comment Solving Differential Algebraic Equations as BVP
I think you may be interested in this site :)
Oct
20
comment C compiler options passed by Mathematica
Have you considered reinstalling the compiler in a directory without white spaces?
Oct
17
comment Numerical solution to two non-linear coupled differential equations
OK, after wasting some time searching in WolframAlpha, I'm pretty sure your equations are simply wrong. What you're modeling is something traveling among Jupiter, earth and sun, 6.67384*10^-11 is the Universal Gravitational Constant, 1.89813*10^27, 5.9722*10^24, 1.98844*10^30 the mass of them, 5.20336, 1 the semimajor axis, 5.19273, 0.99986 the semiminor, Unit: au = 1.496 10^11 m, which is forgotten by you. (I failed to figure out how the 4200 comes from. ) If you had added all these information your post, others will notice the problem much easier.
Oct
16
comment How to Use Mathematica as a C/C++ compiler
Do you mean you want to use Mathematica as a C compiler or an IDE? If you're unclear about this concepts, have a look at this. BTW, Mathematica can't be used as a C compiler, it can be used as an IDE for C, but it won't be convenient. If what you want is just to save disk spaces, you can consider lightweight text editor like notepad++ etc.
Oct
16
comment Using NDSolve to solve a system of coupled PDEs
@RobertMoerman You mean the current plot doesn't match the physical prediction and the plot should be two traveling waves from the origin? If so, My tools at hand can't solve this problem. I just noticed that, strictly speaking, the i.c. and b.c. aren't consistent, can this be a reason for the undesired behavior? BTW, you don't need to accept an answer so fast, it'll be better to wait for 24 hours or more so others may give better answers. And, I just checked the wiki of Gross-Neveu model but got nothing valid, maybe you can talk about this a little more in your question.
Oct
16
comment Numerical solution to two non-linear coupled differential equations
You can add "@xzczd" in your post so I'll get a reminder. You don't need to substitute those values before posting your code here, just see what that OP did in the Edit of his question, that'll make your post look better.