Mathematica
in [Software]
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Some collected information about Dynamic I just did a Google count, and before today, I was up to 91 posts referencing the word Dynamic. As much as I'd like to make this post #100, I'll probably forget, so this will be magic post #96, or something like that. I've posted most (but not all) of these links before about constructing interfaces with Dyna... 26 May 2010 08:02
Dot product confusion On May 25, 6:32 am, "S. B. Gray" <stevebg(a)ROADRUNNER.COM> wrote: SNIP ambiguous, but I assumed the dot product would always commute. Should there be a warning? SNIP Nope, this is just the usual behavior of an inner product of a matrix and vector. The doc. says that Dot[] contracts the last dimensio... 26 May 2010 08:02
Dot product confusion Given ptsa = {{x1, y1, z1}, {x2, y2, z2}, {x3, y3, z3}}; I thought the following expressions would be identical: {aa, bb, cc}.ptsa (* expression 1 *) ptsa.{aa, bb, cc} (* expression 2 *) but they are not. They evaluate respectively as: {aa x1 + bb x2 + cc x3, aa y1 + bb y2 + cc y3, aa z1 + bb z2 + c... 27 May 2010 07:03
Just some thousands of combinations... Subsets[Range[90],{5}] should print all the Binomial[90,5] = 43 949 268 combinations. On my PC (4gb RAM) Mathematica 7.0 claims "Not enough memory". By the way, I only need to print some thousands of these combinations, then Subsets[Range[90],{5}, 3000] works fine. But it prints the first 3000 combination i... 26 May 2010 08:02
Intersection of sublists on date and making a 2D list from a 3D Intersection@@(#[[All,3]]&/@list) will handle a variable number of groups. On May 21, 9:42 pm, Garapata <warsaw95...(a)mypacks.net> wrote: I have a list with the following dimensionality: Dimensions[list] Dimensions[list[[1]]] Dimensions[list[[2]]] Dimensions[list[[3]]] {3} ... 23 May 2010 03:52
Usage Messages; % evaluates to Null. Why? Group: I'd like to pull documentation on particular functions and display the information with TableForm[] (mainly for organizing teaching notes). My first thought was to evaluate ?SomeFunction and then grab the text using %[[]]. Problem: there don't seem to be any parts I can grab: TableForm[{Information[T... 23 May 2010 03:52
SQLExecute with an argument A bit simplified but I hope this explains my problem... This works: SQLExecute[conn, "=E2=80=A8SELECT column1, =E2=80=A8FROM table1=E2=80=A8 WHERE dateColumn >= '2007-02-15'"=E2=80=A8]; But I'd like to make the date ('2007-02-15') a parameter. I've tried this: SQLExecute[conn, "=E2=80=A8SELECT column1, F... 25 May 2010 06:56
Intersection of sublists on date and making a 2D list from a 3D one I have a list with the following dimensionality: Dimensions[list] Dimensions[list[[1]]] Dimensions[list[[2]]] Dimensions[list[[3]]] {3} {130, 3} {126, 3} {191, 3} I think of it as 3 groups, each with a different number of rows, but each of these rows has 3 columns. Of the 3 colu... 23 May 2010 03:52
Numerical solution of differential equation This is classical Skyrme model equation. My approach was: 1) find asymptotic behaviour and 0 2) shoot from far end close to zero Below is the working (much simplified, but still devoted to generalized equations of this type) cut from my old notebook. In 7.0 Your can use direct NDolve method "Shooting" Somet... 27 May 2010 07:03
Why does EvaluationMonitor stop when NDSolve doesn't? Dear Group, I have an ODE set, which I send in to NDSolve. It solve more-or-less correctly, but indicates a stiffness somewhere. As a matter of fact, I cannot rely on the InterpolatingFunction output, so I'm saving the actual datapoints via EvaluationMonitor (or StepMonitor). But the monitor stops when the stiff... 22 May 2010 00:53 |