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visits member for 2 years, 11 months
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May
16
answered Treat strings as variables?
May
13
comment How to generate a unique file name similar as that created by CreateTemporary
it probably is worth noting that it is common practice to use such random strings as "global unique identifiers" (GUID). Of course they are not guaranteed to be unique, but only have probabilities of almost 1 to be so. See e.g. the wikipedia article on GUID for details. From the format of the strings I could well imagine that the conventions mentioned there are what Mathematica uses for CreateTemporary, or at least something very close...
May
6
comment NDSolve producing an overdetermined system
for me the error message seems to be very clear: you have 3 differential equations but want to solve for 4 functions. What is em? Why don't you have an equation for it?
May
6
comment Why do NDSolve and OutputResponse not evaluate non-analytic functions numerically?
It probably should be noted that it does help to start from a value larger than zero for NDSolve (at least if one adopts the initial condition), but not for OutputResponse...
May
2
revised How to change a parameter dynamically inside NDSolve
distangled some lengthy unclear sentenses (hopefully)
May
2
answered How to change a parameter dynamically inside NDSolve
Apr
30
answered Parallel computation of a system of differential equation
Apr
30
comment How to save the results in an identical Excel file (.xls) in each iteration of a Do loop
the standard Export for excel files can only write content in one go. Of course you can completely overwrite the file for each line, which is inefficient but probably not too problematic. Other than that I see the following possibilities: write to a text file (or CSV) line by line, for these appending is simple and efficient. Depending on the data, you won't loose much compared to an excel file. If you really need excel, you could use NETLink to do what you want, if you search for "NET excel" you'll find many Q+A to start...
Apr
27
awarded  Nice Answer
Apr
26
answered Garbage collection for memoized functions on subkernels
Apr
26
comment Prevent package from being opened in a notebook interface
well thats what I would probably try to do in your situation, but as I said, my experience with .NET is very limited. I would know how to do that in Java or C, so I can hardly imagine it wouldn't be possible with .NET.
Apr
25
comment Prevent package from being opened in a notebook interface
Honestly, I don't know .NET very well, but there are for sure binary libraries/assemblies/object-files that another .NET program can load? If you provide such a binary for them to load from their .NET code that wouldn't make much difference to calling an encoded package file via NETLink for them, would it? You could even sell that as a feature as they wouldn't have to bother with NETLink in their code :-)
Apr
24
comment Dynamic Syntax - Evaluate AppendTo as the second argument
@m_goldberg: I think the missing not makes my previous comment superfluos :-)
Apr
24
comment Prevent package from being opened in a notebook interface
what about compiling the compressed code string into the NET assembly and send it to to the kernel for uncompress/evaluation? Then it would not even live as a file in the filesystem on the executing machine...
Apr
24
comment Dynamic Syntax - Evaluate AppendTo as the second argument
@m_goldberg: you say "only seems to work reliably", but does it work at all and is it supposed to? I would have said it most probably isn't even meant to work, but honestly don't know what actually is the "documented" behavior that I could expect. I also can't see that a naked Dynamic with a 2nd argument does anything relevant concerning its 2nd argument, other than quietly ignoring it. Am I missing something here?
Apr
24
comment How to copy a function by value?
it might well not be the right choice for your problem, but I think you should be aware that for those cases where you treat a function as an object, using Functions is often more appropriate than downvalue-definitions. When using func1=Function[x,x^2] for the first definition and func1=Function[x,-x] for the second your example will work as you want...
Apr
24
comment Prevent package from being opened in a notebook interface
I don't see why it would be problematic to open an encoded package or mx file in the frontend, you can never prevent anyone to open such a file in a text editor which will show exactly the same information. Can you explain? Or do I miss your point?
Apr
21
comment an NIntegrate inside a manipulate in mathematica was working and suddenly won't work now. it says indeterminent and it doesn't make any sense why
What I find really strange is that you say you got meaningful results from this before. You have exponentials in your expressions with arguments like -(1.88*^11 + 0.00091823*(kp^2 + kz^2) + kz*Vd)^2/(8*(kp^2 + kz^2)) which will give values in the order of -10^16 for your parameters. Taking an exponential of that clearly gives an underflow. You could try to switch to arbitrary precision calculations but I think you'd be better off trying to rescale your variables to avoid such extreme numeric values...
Apr
20
comment Understanding of method for NDSolve
As for your remaining question: yes, it looks like NDSolve was choosing LSODA, you can find several places where it is mentioned by searching for LSODA in the documentation. One prominent place to look for some more information and references is (stiffness detection)[reference.wolfram.com/mathematica/tutorial/…. The advanced documentation for NDSolve (use this string in the documentation center search field: tutorial/NDSolveOverview) is quite detailed and well worth reading...
Apr
20
comment Understanding of method for NDSolve
I have formatted the code sections in your questions. I think it would make sense if you learn to do that yourself, the syntax is well documented. The higher the total quality of your answer, the more likely you will get an answer. It is also common and welcome to give answers to one's own question, so if you find an answer yourself there is nothing wrong in answering your own question and even accept that.