Mathematica

Will FindFit invoke LinearProgramming?
Will FindFit, if given a linear problem with simple bound constraints, and possibly NormFunction->(Norm[#,1])&, automatically treat as a Linear Program (specifically a Least Absolute Deviations formulation of an LP)? How might one find this out? ... 7 Apr 2010 03:29

customized sliders
I came across the following code in the documentation (on Advanced Manipulate): ValueThumbSlider[v_] := ValueThumbSlider[v, {0, 1}]; ValueThumbSlider[Dynamic[var_], {min_, max_}, options___] := LocatorPane[ Dynamic[If[! NumberQ[var], var = min]; {var, 0}, (var = First[#]) &], Graphics[{AbsoluteThi... 6 Apr 2010 07:28

Fix for "Mathematica has quit unexpectedly" on Shift+Option start-up
WRI support have suggested to me on several occasions the Shift+Option restart procedure to reset Mathematica somewhat. This however was causing Mathematica to crash on start-up. Here's the solution that worked for me, ---------------------------------------------------------------------------= - Hello, When... 6 Apr 2010 07:28

Exporting a vector
Hi all, I want to export a vector from a loop statement with two counting variables, i,j. as an example: w0=1;dk=1; eq= a function of w and k; Do[{w[i] = i*w0}; {eq1[i] =eq /. w -> w[i]}; {k[j] = j*dk}; b[i, j] = eq1[i]/.k-> k[j]}];bet[i] = Min[bet[i, j]], {i, 1, 5}, {j, 1, 5}] ; When I try to name the Do l... 6 Apr 2010 08:33

Epic Epic HeavisideTheta problem
Hi all, I have encountered what I think is some sort of a serious problem with HeavisideTheta[]. Essentially I am using HeavisideTheta[] to switch on and switch off a simple (sinusoidal) blending function that is applied to the small and large z approximations of a Hypergeometric1F1[a,b,z] in order to get an ana... 5 Apr 2010 08:17

Any answer for this ParallelDo error
Hallo Group, Here is a harmless piece of code. Clear[a]; t=AbsoluteTime[]; a=ParallelTable[0,{i,1,20},{j,1,50}]; DistributeDefinitions[a]; mat=ParallelDo[a[[i,j]]=If[PrimeQ[(i^3+j^5)]==True,1,0],{i,1,20},{j, 1,50}]; AbsoluteTime[]-t The error is something like Set::noval: Symbol a in part assignment d... 6 Apr 2010 08:33

if using Mathematica to solve an algebraic problem is like copying
from someone else, then consider this article, which suggests that students (at MIT, at least) learn significantly less, in some sense by copying their homework. http://web.mit.edu/newsoffice/2010/homework-copying-0318.html Of course this would be similarly true for other computer systems. While the details ... 6 Apr 2010 08:33

size of ticks
Hi guys, easy question this time. I want larger ticks on a plot. I know that I can use TicksStyle->Directive[Thickness[0.005], 50] to set the Thickness of the Ticks (here to 0.005) and the FontSize used for numbering the ticks (here to 50). I didn't figure out how to make the ticks longer. Thickness makes them... 6 Apr 2010 07:28

Solutions provided for "combining elements
Thank you so much to everybody who helped my with my question. I have posted all the solutions that I received in this message so that they can be available to the whole group. The author of each solution is noted. Jason Ebaugh ***ORIGINAL QUESTION*** How could I go from: {h,e,l,l,o} to {hello}? That... 5 Apr 2010 08:17

Creating a hybrid cell
I am doing a calculation. Let us say that the result of the calculation is in variable X1 (which was extracted from a list using [[]] type constructs - unimportant, but it is a result). I want to add text cells later in the notebook that refer to the value of X1 (not the string "X1"). I have tried doing this with... 17 Apr 2010 06:24