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Feel free to correct the grammar mistakes in my posts.


Feb
12
comment Error When Creating Package
……Are you sure? I can't fix OP's package by these steps, and even with the ClearAll existed, ?select still gives the desired result. I'm using v8.0.4
Feb
12
comment Error When Creating Package
……You mean the only necessary thing here is to add column::usage = "" and remove the ClearAll[select, where]; ?
Feb
12
comment Error When Creating Package
Have you set the format of the cell as Code or initialize the cell contained your code or just write your package not in a .nb file but in a .m file at the very beginning?
Feb
12
comment Get Coordinates 4 significant digits limitation
I think you forgot to change your function names in the CoordinatesToolOptions.
Feb
9
comment How can I get Mathematica to produce better Fortran code?
……Because it's not free?
Feb
7
comment Nonlinear System of ODEs
Your problem is a combination of simple mistake. eqn2 = Φ'[x] == should simply be eqn2 = , Φ[0] = 0 should be Φ[0] == 0. Then since β has no exact value, I think you need ParametricNDSolve.
Feb
7
comment Why is my answer being displayed with “Subscript^(0,1)[a,b]”?
You can select the cell contained your code and press Ctrl+Shift+I to change it into InputForm before you paste your code here.
Feb
5
comment Complicated condition for system of differential equation
Just come to mention that Clear All; doesn't make any sense……What you need is Clear["`*"]
Feb
5
comment How to open directly the help/reference window from a notebook
You can simply write down the symbol and then press F1.
Feb
5
comment Green's Function in Mathematica
v5.2……well it's really too old, a lot of improvement has been made in the following version……you'd better upgrade your Mathematica.
Feb
5
comment Mathematica can't find constants for this differential equation
Well, I doubt if Assuming and $Assumptions will help in this case for they only work for functions with the option Assumption. DSolve doesn't have this option, and there seems to be no evidence that DSolve has called functions with this option…
Feb
5
comment Green's Function in Mathematica
Er… Just to confirm, DSolve won't work without Assuming in this case? Are you in v9? In v8.0.4, the Assuming isn't needed.
Feb
5
comment Green's Function in Mathematica
Your first code sample doesn't work? It is solvable in v8.0.4.
Feb
5
comment Kinetic Friction in Mathematica, weird behaviour
I found it, see the 3rd approach in my answer.
Feb
4
comment refer to result of cell above current cell?
Yeah, the number depends on the evaluation order. If you need to use the output of a specified cell for times, it's better to give a name to it.
Feb
4
comment refer to result of cell above current cell?
You can use the index of the output to refer to it. For example, if it's Out[32] you can refer to it by %32.
Feb
4
comment Kinetic Friction in Mathematica, weird behaviour
In v8.0.4, MaxStepSize -> .01 doesn't work, but MaxStepSize -> .03 does. I think that a more strict control for the step is needed, though I don't know how to achieve that…
Feb
4
comment Error in using EventLocator in NDSolve
Without a complete code sample, it'll be hard for others to figure out the reason… If the original definitions of V and G are really long, you can provide a simplified version reproducing your problem. BTW, if you add @xzczd at the beginning of the comment, I'll get a remind.
Feb
1
comment How to choose MaxStepFraction for optimal speed of NDSolve
I just come to mention that all of your MaxStepFraction don't "converge" for L = 5 in v8.0.4. (Vista Home Basic 32bit. BTW, 2GB memory so it can't bear the L = 7.5 case 囧.) And according to my experience, warning messages of NDSolve isn't a big deal for many cases. With the method mentioned in this post your warning will disappear but in fact the result doesn't change much.
Jan
29
comment How to use Compile with NDSolve function for large no of differential equations?
I remembered once I read some material (probably in somewhere inside the document) that said NDSolve will use Compile automatically…