10,186 reputation
1745
bio website
location
age
visits member for 2 years, 11 months
seen 32 mins ago

Mar
12
comment Running a Numerical Simulation on a System of Differential Equations with unique initial conditions
@VincentTjeng: I'm still not sure whether I understand your initial conditions correct: If what you are saying is that the angle of the boundary node is a predefined "forced" function, then I think you'd best split your total time interval into two parts: for the first part solve the system of n-1 oscillators and Θ[0,t]=t/10*2π fixed (Θ[0,t] then isn't a dependent variable anymore). Then use the final states of that solution as initial conditions of another call to NDSolve for the full system with n oscillators for 20<t<tmax. Does that make sense?
Mar
12
comment Running a Numerical Simulation on a System of Differential Equations with unique initial conditions
@VincentTjeng: I think your question still needs some work: the equations are presumably still not correct (e.g. Mg should progably be M*g or M g), the comments miss a *) and the part about the initial/boundary conditions is still not clear. Isn't the angle of the first oscillator a fixed function so that it isn't a dependent variable anymore? You'll still need to fix the initial conditions for the others, then. If you have a solution involving While, why don't you post it so we have something to start with?
Mar
12
comment Can I set 'no-go' values in a Manipulate slider?
What Manipulate uses as default control for numeric values is a Manipulator which also has the Exclusions option and is called exactly like a Slider...
Mar
12
awarded  Enthusiast
Mar
8
comment Go to definition of symbol/variable
@Nasser: when you copy Mathematica source code from the notebook, it basically does a "convert to input form" in the background and the result is plain text with fixed line breaks which of course is a form for which line numbers make sense. What really is contained in the notebook (except for specially styled cells) is more complicated, and for that there isn't a meaningful line number. I'm not saying that all that is perfect and couldn't be improved, but there is a reason for it to be as it is. If in doubt, open a .nb-file in a text editor and make a guess about line numbers...
Mar
8
comment Go to definition of symbol/variable
@Nasser: what is somewhat ridiculous is the fact that Get reports line numbers for syntax errors in package files but you need external editors to actually find those lines. So yes, there seems to be room for improvement...
Mar
8
comment Go to definition of symbol/variable
@Nasser: I think the problem with source line numbers is that the structure of a notebook-expression isn't line oriented: there isn't anything like a defined line number within a notebook. This has been discussed several times in questions about Mathematica files and version control systems, which you can search if interested in more details. When used as a package file editor, it would in principle be possible to define line numbers and the package-file editor for Wolfram Workbench actually has them...
Mar
8
comment Go to definition of symbol/variable
@Ferio: I don't think it is possible to solve this in general. As in Mathematica there can be many definitions for one symbol and these could in principle be distributed over different locations and files there isn't something like single point of definition. Maybe that's the reason why no such functionality is available. When you use a personal convention to mark where a certain symbols definition appears it should be simple enough to write something. If you are interested in such an approach I'd suggest to indicate that in your question and I'm sure you'll get some help...
Mar
7
awarded  Nice Answer
Mar
5
revised How to programatically save a notebook created by CreateDocument
added short explanation and added note about Notebooks[]
Mar
5
comment How to programatically save a notebook created by CreateDocument
@rcollyer: I bet your answer would have been somewhat more elaborate, though :-)
Mar
5
answered How to programatically save a notebook created by CreateDocument
Mar
4
comment In .NET/Link, how do I not open multiple kernels?
Have you looked at webMathematica? It is Java based, so it isn't a perfect fit for your ASP.NET setup, but it has the key feature you seem to need: it provides a queueing system for access to a pool of preinitialized kernels. It is also possible to create webservices which use such a pool of kernels and which your ASP.NET application could use. You even might ask the support at WRI whether it is possible to use only the kernel pool feature from ASP.NET more directly...
Mar
2
comment How can I analyse Mathematica data using Wolfram|Alpha?
@MarkMcClure: My point was that the WolframAlpha commands generally send session data, but it's up to the servers interpretation of the free form input whether it makes use of that data. For the a+2 and plot a cases it indeed looks like it doesn't make use of the session data and your interpretation of what happens seems correct. The session data dialog indicates that the value of a is actually sent to the server, but then is ignored. Anyway, I fully agree that this is taking us far away from the original question...
Mar
1
comment Copying a symbol using a subpackage
@Ronny: I think for production code you would want to insert an additional pair of Begin and End: as it is written now, you'll also export copy, prop, new and org along with g...
Mar
1
answered Basic questions about running Mathematica
Mar
1
comment How can I analyse Mathematica data using Wolfram|Alpha?
@MarkMcClure: I don't think what you say about a only being evaluated in your Mathematica session is true: depending on your preference settings ("Internet Connectivity" -> "Wolfram Alpha Settings") there is "session data" sent to the WoframAlpha servers -- and that includes the values of global variables, as can be seen from the "Session Information" dialog that pops up when you set "Mathematica Session Info" to "Ask before sending". As for the syntax issue, I think this is by design: "Free-form natural language input" looks pretty much like the opposite of "reliable syntax" :-)
Feb
26
answered Mathematica 9.0 problem: ParallelTable with SQLExecute
Feb
25
comment Mathematica 9.0 problem: ParallelTable with SQLExecute
just another comment to ring a bell, forgot that in my last. Sorry for the noise...
Feb
25
comment Mathematica 9.0 problem: ParallelTable with SQLExecute
Not sure but I think you would need to ParallelEvaluate the conn=OpenSQLConnection[...], so that each Kernel has it's own connection to the database. Note that this is different than creating a list of connections on the master and distributing them, which I definitely would not expect to work. I wonder how the above could work with version 7, though. Are you sure that with version 7 the ParallelTable was really executed in parallel?