Mathematica

Evaluate to...
I don't know if it is available & I cannot find it... Some notebooks I use are fairly large, and after starting Math I usually evaluate them all. Sometimes however I'd prefer to evaluate them up to a certain line, if for example I have some problems at that point. It would be useful to have a command similar t... 21 May 2010 07:17

Equals, Less, Greater, etc; Confused by this simple
I think we should not forget about the evaluation aspects of Mathematica: In[1]:= n = 0; a >= a /. a :> n++ Out[2]= False However, by the same logic <a> may not be equal to itself in some cases. If we use Unevaluated to simulate the situation where a==a would not evaluate, we get also: In[3]:= Unevaluat... 19 May 2010 20:29

Basic histogram
How do I plot a basic histogram from a list of values. This simple list will not plot - arrData3 = {1067., 2874., 2306., 2828., 2989., 838. , 1302., 2762., 682., 2108., 2902., 3001., 1997., 1269., 3110., 2496., 1911., 2266., 2244., 1074., 567., 754., 2987., 1893., 3809., 419., 745. , 1791., 578., 1156., 777... 21 May 2010 07:17

How to Enable Automatic Recalculation
Hi Vic, Easy. Use SetDelayed i.e., := instead of Set (=). Set calculates the value of b at definition time whereas SetDelayed causes the value if b to be calculated when b is actually used. This is actually very basic stuff that is easily found in the manual. Cheers -- Sjoerd ... 19 May 2010 20:29

Orthogonal Distance Regression available?
Is there any straightforward way to do Orthogonal Distance Regression (ODR) in Mathematica? If not, this would be a nice feature to have in Mathematica. Background: Regular nonlinear least square fitting minimizes in one dimension the distance between the data and some function. ODR does it in all dimensions sim... 27 May 2010 07:03

Error when attempting to save Graphic to file
Hello, I'm attempting to write a function which, when evaluated, will prompt the user for a file name and then - if the dialog isn't cancelled - save a specified graphic to the file. My first attempt is as follows (please note that the variables 'linesToDraw' and 'pointsToDraw' are defined elsewhere by anoth... 19 May 2010 08:13

Variable MaxStepFraction in NDSolve
Is it possible to specify in NDSolve a variable MaxStepFraction? That is, i'm integrating within {x,0,100} and i want MaxStepFraction=1/500 in {x,0,1} and MaxStepFraction=1/100 in {x, 1,100}. ... 19 May 2010 08:13

Numerical solution of differential equation with boundary values
Hallo, I need to solve the following differential equation: (1/4 r^2 + 2 Sin[F[r]]^2) F''[r] + 1/2 r F'[r] + Sin[2 F[r]] (F'[r])^2 - 1/4 Sin[2 F[r]] - (Sin[F[r]]^2 Sin[2 F[r]])/r^2 == 0 with boundary values: F[0]==Pi, F[Infinity]==0. I tried NDSolve, but failed to get a solution. How can I solve that ... 19 May 2010 20:29

Equals, Less, Greater, etc; Confused by this simple output.
Can someone offer an explanation for the following output?---I'm trying to understand why it makes sense for Mathematica to be set up to respond like this. (Of course, feel free to point out any glaringly obvious math examples.) In[1]:= {a == a, a <= a, a >= a, a < a, a > a} Out[1]= {True, a <= a, a >= a, a < ... 19 May 2010 20:29

combining ArrayPlot with ListLinePlot
I have a strange problem with combining 2 plots: ap = ArrayPlot[Transpose[l]] lp = ListLinePlot[{a, b, c}] Each of 'ap' and 'lp' is shown correctly. However combining them via: Show[ap,lp] always shows just ap. Dimensions[Transpose[l]] is {44, 2000} a,b,c have same dimension {2000} I feel like I am ... 22 May 2010 23:37