Mathematica

Scoping constructs Block, Module, ModuleBlock
On 7/22/2010 2:42 AM, John Fultz wrote: [...] I didn't look at your original code, but I think I probably know why your use of Block and Dynamic together failed. The principal point is that Block introduces an environment where variables can be temporarily redefined, but that environment evaporates the ... 4 Aug 2010 05:59

NDSolve - how to bypass safety chceck?
I have got an DDE/ODE equation: for parameter d < 0.8 the solutions are non-chaotic, for d > 0.9 the solutions are chaotic. Mathematica NDSolve works fine for d < 0.8 . The problem is NDSolve has got a kind of "safety chceck" - for d > 0.9 it gives a warning "Maximum number of ... steps reached at the point"... 31 Jul 2010 03:13

A Question About Directive [off-topic]
No, not really! As with nearly any programming language, it's possible to write nearly inscrutable code -- even with Mathematica. In APL, lots of folks did, and may still do, try to write "one-liners" and use cryptic names for variables and functions. But lots of APL code, even though very, very terse, coul... 27 Jul 2010 05:09

Problem with Min Max between two functions
Dear Mathgroup, I have the following function R1=1.029 R2=3.892 R3=8 e1=250 e2=11.8 e3=80.5 i=pi/12 spherenear[x_,y_]:=((R3^2-x^2-y^2)^(1/2)) spherefar[x_,y_]:=-((R3^2-x^2-y^2)^(1/2)) emptynear[x_,y_]:=Min[Re[spherenear[x,y]],Re[(R2^2-x^2)^(1/2)+y*Tan[i]]] emptyfar[x_,y_]:=Max[Re[spherefar[x,y]],Re[-(R2^2-... 3 Aug 2010 07:03

FindRoot + Compile = incompatible (?)
Has anyone ever run into the problem of trying to use Compile'd functions within FindRoot? The error message is: "CompiledFunction::cfsa: Argument y at position 1 should be a machine-size real number." [Yes, the function still evaluates but in doing so the purpose of compile & speed gets defeated.] Th... 27 Jul 2010 05:09

Need to align data from sublists to Union of dates
Below are some thoughts about how to address this questions. After finding the union of all times (which you did in the question), then find the position of those times in the sublists. then lookup the values corresponding to those positions. Finally, combine the results. (*This simulates the data format you... 26 Jul 2010 09:25

de-nesting complex nested lists
If one has an irregularly nested list like {{1, 2, 3}, {1, 2, 4}, {{1, 2, 3, 4}, {1, 2, 3, 8}}, {{1, 2, 9}, {{1, 2, 13}, {4, 5, 6}}}}, How might one most easily transform this into a list of uniform Depth 2 ( {{1,2,3},{1,2,4},{1,2,3,4},{1,2,3,8},{1,2,9},{1,2,13},{4,5,6}} ) ? Thanks in advance, Michael ... 31 Jul 2010 03:13

Documentation on (Color) Blend
Group: The documentation on Blend[], in the "Possible Issues" section, contains the following example. ---------------- In plot functions, use ColorFunctionScaling to control global scaling of variables: Table[DensityPlot[x, {x, -2, 3}, {y, 0, 1}, FrameTicks -> None, ColorFunction -> (Blend[{Red, Green}... 26 Jul 2010 09:25

mathematica gives strange result
Im trying to find a solution to equation DSolve[-y''[x] + ((Csc[x])^2)*y[x] == y[x]/4, y[x], x] but mathematica gives me some strange result with expresion (-1+cos^2(x))^(1/4) in it. Why is that and how should i interpretate this? ... 27 Jul 2010 05:09

Linking my fortran subroutines with Mathematica
Hello I am new to Mathematica. Although I have searched the web for answers on how to link fortran to Mathematica without buying MathCode F90, I have not found good examples on how to link Fortran to Mathematica. All my fortran functions were modified to accept a C-wrapper. I did that to link them to another ... 27 Jul 2010 05:09