For questions specific to Version 7 of Mathematica.

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18
votes
0answers
156 views

M9 performance regression for Fold?

I noticed an over 10x performance drop on Mathematica v9.0.1 (as Oleksandr R. commented, also v8) compared with v7.01 for this code: ...
15
votes
4answers
1k views

What is the right way to rotate an array?

Suppose I have an array, not necessarily square: a = $\left( \begin{array}{ccc} 1 & 2 & 3 \\ 4 & 5 & 6 \\ 7 & 8 & 9 \end{array} \right)$ I want to rotate it like one ...
13
votes
2answers
311 views

Problem importing URL with Greek characters

I'm considering buying a car. So I thought why not make a web-crawler in Mathematica to pile-up car data? Brilliant idea. Then I found this Greek website, gocar.gr, which just so happens to have all ...
12
votes
6answers
494 views

Sort+Union on a list

Probably this is too trivial question for this forum but for some reason I am not getting it on my Mathematica 7 so far. I have a list ...
12
votes
2answers
318 views

Internal “Periodical” functions in version 7

In version 7 there exist these Internal` context functions: ?Internal`*Periodical* ...
11
votes
2answers
381 views

backward compatibility

When producing or enhancing code, it is tempting to use recent new primitives of Mathematica introduced in version 7 and 8, but for library code or in preparation or future version change in ...
9
votes
3answers
347 views

Why does Hash return different values in Version 7?

This function does not work correctly for me. The generated Gravatars do not match the ones actually produced by using the corresponding address. The problem was traced to differing output from the ...
8
votes
2answers
338 views

Problem with ContourPlot3D

The following line works fine: ...
7
votes
4answers
282 views

Unexpected behavior from GatherBy in version 7

I have come across what appears to be a bug in GatherBy. It appears similar to the problem of using Table[Random[], {1000}] in ...
7
votes
3answers
365 views

Plotting a 3D list causes kernel to crash if x and y axes have vastly different scales

I have access to two versions of Mathematica, version 7.0.1 on Linux and version 8 on Windows. When I try the following two lines on version 7, the kernel quits when it tries to plot. In version 8 ...
7
votes
1answer
818 views

Mathematica: Label specific vertices in GraphPlot

How can I label particular vertices in GraphPlot? And have the arrows space out accordingly, for the width of the label? I have Mathematica 7, but I think this question applies to all versions. ...
7
votes
2answers
218 views

Tick marks shrinking with ImageResolution [duplicate]

High resolution PNG export is handy for print quality plots, however tick marks are not scaling properly. Does anyone know a solution or a work-around, preferably for M7 (on Win7)? ...
7
votes
1answer
106 views

$InputFileName backwards compatibility

What would be a good replacement for $InputFileName (which has been added recently to Mathematica 8) to achieve backwards compatibility with let's say M6 and M7? I ...
7
votes
1answer
83 views

Bug in GeneratingFunction?

According to the documentation GeneratingFunction[a[n],n,x]==Sum[a[n]x^n,{n,0,Infinity}] However, for $a_n=1/(n+2)$ I obtain ...
7
votes
2answers
709 views

Legends in combined Plot and ListPlot

I have a set of data ...
6
votes
3answers
424 views

How to randomly erode a 3D distribution of points with Mma 7.0?

Suppose we have a 3D distribution of points, like the spherical ball example below : ...
6
votes
1answer
285 views

PrintTemporary in ParallelTable

I thought of a possible answer to Monitor doesn't work with ParallelTable but it doesn't work as I hoped it would. This accumulates print cells instead of deleting them as intended. Can it be ...
6
votes
0answers
120 views

Mathematica 7: “LessEqual::nord:” error when using NMinimize on a real function

I encounter a problem (Mathematica 7) similar to Strategies to avoid LessEqual::nord in NMinimize? but the advised strategies don't work for me. Also, I get different results with different ...
4
votes
1answer
75 views

Animated matrix will not work?

I want to export a list of matrices as a gif so that they will appear one after another 2 seconds apart. Ive tried the following but when I open it up it only does the first two matrices, I have 10 ...
4
votes
1answer
86 views

Is it possible to enable syntax highlighting for \[Function]?

This is a bit of a long shot but I am wondering if it is possible to enable syntax highlighting in a function defined with \[Function] without resorting to anything ...
4
votes
1answer
201 views

Sporadic bug in Mathematica 7.01.0 MatrixPower and/or Eigensystem functions on floating-point symmetric matrices with repeated eigenvalues

Note: From the comments submitted below by other StackExchange users it appears that this apparent bug was fixed sometime after version 7.0.1. I asked a vague variant of this question a few days ago, ...
4
votes
0answers
58 views

Error with String patterns producing Removed[“$$Failure”]

While working on How to capitalize the first letter of each word in a string and trying to understand why certain characters were not considered letters I tried this: ...
4
votes
0answers
213 views

NullSpace[_, Method->“OneStepRowReduction”] is sometimes wrong; how can I work out when this happens?

(This is on MMA 7.0.1.0 on OS X) I've just found a large matrix m for which NullSpace[m] and ...
3
votes
3answers
190 views

In Mathematica 7 for Windows, is it possible to use custom GUI magnifications?

I am running Mathematica 7 on Windows XP Pro. I often use the magnification feature to zoom in on Plots, ListPlots, and ...
3
votes
3answers
159 views

Colorize a 3D distribution of points according to density

Suppose we have some random 3D distribution of points. I'll use the spherical ball defined below as an example and a starting point for the discussion here : ...
3
votes
1answer
123 views

Sorting an Array with words in different languages

Array consists of words of different languages. I need to sort elements in reverse alphabetical order and make a list of elements, which consist of english letters. Example of array which consist of ...
3
votes
1answer
60 views

Bug with LinearProgramming on Integers?

With Mathematica 7: LinearProgramming[{1, 1}, {{0, 0}, {1, 1}}, {1, 1}, Automatic, Integers] gives wrong result {0,1}. But ...
3
votes
2answers
198 views

How can this DivisorSigma code be made fast?

Since Project Euler problems are now fair game for questions I have a question of my own. A certain problem* states: For a positive integer n, let σ2(n) be the sum of the squares of its ...
3
votes
0answers
89 views

An recurrence equation that can be solved in version 7 but not in version 8

A friend of mine showed me this code sample: RSolve[{a[n] == a[n - 5] + 1, Sequence @@ Table[a[i] == 1, {i, 5}]}, a[n], n] // Timing It's solved by version 7 in ...
2
votes
1answer
133 views

ListPlot - plotting values with different range

I have three tables: L, S and U. In first table I have values from range (0,1), in second ...
2
votes
1answer
390 views

How to take the derivative w.r.t. an arbitrary function?

EDIT: The answer posted by @Jens works for built-in functions only. However I'm starting to wonder if this is related to my Mathematica install somehow. I have version 7. Here is an example in the ...
2
votes
1answer
108 views

How to extract the bin width from a Histogram made with an automatic binning method?

I am using the Scott binning method with Histogram and Histogram3D to plot some data. How could I find out the bin width chosen ...
2
votes
2answers
122 views

How can I style a TabView?

I have been trying to style a TabView like in the examples on the Wolfram CDF site, where they have custom sizes and backgrounds with images or gradients, but I am ...
2
votes
1answer
139 views

Export to mat file does not work

I use this command from the Mathematica documentation center Export["1.mat", {"t" -> {{1,2,3}},"u" -> {{4,5,6}}}, "LabeledData"] to save data as mat file ...
2
votes
1answer
146 views

Version 7 and 8, different behavior of NSolve. Is it reproducible?

I noticed the following difference, and I wonder if it's a problem of my system or the results difference is actually due to the two different versions ...
2
votes
0answers
72 views

Det and MatrixRank freezes on SparseArray with nonzero default value

Why does the following simple code never come to an end (at least with version 8) n = 5; mat = SparseArray[{i_, i_} -> 1, {n, n}, -1/(n - 1)]; MatrixRank[mat] ...
2
votes
0answers
340 views

Simple contour integral with a parameter gone wrong

I run into the following problem, I tried to evaluate a very simple integral: Assuming[ a > 0 , Integrate[Sin[a*s]/(s - I)^2, {s, -Infinity, Infinity}]] ...
1
vote
2answers
198 views

How to blend some colors on a curve

I need to define a color gradient on a 3D curve, but I'm having some problems with this. Suppose we have a 3D curve defined as a parametric function of some real variable ...
1
vote
2answers
127 views

Converting polygon to graph in V7

I've unsuccessfully tried many ways of converting polygon points into a graph using Mathematica 7, and I am frustrated. I looked at this post, but it doesn't work: ...
1
vote
1answer
125 views

ListPlot doesn't shows all points [closed]

I have a table: p1 = Table[(Binomial[2000, k]*StirlingS2[1386, k]*k!)/(2000^1386), {k, 1, 1386, 1}]; I used ListPlot[p1] ...
1
vote
1answer
193 views

Version differences in Parallelize

I am having a problem which I guess is due to version difference. I have to generate a list of unitary matrices, which I can do easily. However I came to know about ...
1
vote
1answer
141 views

Spacer and Text in Graphics going Awry (in Mathematica 7)

Use of a vertical Spacer in justified text inside a graphic isn't working as required. The result in the green box looks right, but when this is placed in a ...
1
vote
1answer
96 views

TextCell going awry due to ImageResolution (in Mathematica 7)

Can anyone see how to fix this text display? The example is from a larger project. I need to export the graphic at high resolution, but the text is going wrong. ...
0
votes
1answer
256 views

Table - find index of the maximum element [duplicate]

Let's suppose that I have table t = {1.23, 3.4, 10, 34, 1.78, 0.98, 12.56}. To take the biggest element I can use Max[t] ...
0
votes
1answer
42 views

Showing result of derivative and other functions [closed]

I have a problem with my Mathematica 7.0 When I write: Derivative[x^2, x] Mathematica returns as result : ...
0
votes
1answer
84 views

Missing some packages?

I am trying to use a program written by someone else. When I run the program, I am supposed to get a number as a result, however, what I got is some complicated result with "InterpolatingFunction" ...
0
votes
1answer
117 views

Error changing edge thickness in a GraphPlot

I'm having some problems with the Mathematica graphics inspector. I want to make a graph with the following code: ...
0
votes
0answers
35 views

Number precision in a list [duplicate]

I have list with elements: ...
0
votes
1answer
51 views

Specifying Table/grid dimensions in version 7

The result of my calculations is quite large list (nested list to be precise). I would like to improve its visualization, to make it more legible, by setting the number of columns to let's say 5. ...
0
votes
0answers
138 views