5
votes
1answer
89 views

Why does Arrow not work well with Scaled coordinates in 3D?

I am a little puzzled by the fact that if I try to use Arrow with Scaled coordinates in 3 dimensions the arrowheads are all over ...
5
votes
0answers
130 views

Issue with FindCurvePath

I have a problem with the function FindCurvePath. In some cases it crashes the Mathematica 9 Kernel. Here an example, where it crashes the kernel: ...
6
votes
1answer
66 views

Infix strange behaviour

Maybe this is a bug or maybe Infix acts differently than the other functions. The fact is that both: TreeForm[Infix[f[x, a]]] and ...
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 ...
20
votes
1answer
260 views

eigenvector bug?

I have a fairly simple $3\times3$ complex matrix, $$ M=\left( \begin{array}{ccc} \frac{7}{2}-\frac{i}{2} & -1+i & \frac{1}{2}+\frac{5 i}{2} \\ -1+i & 5+i & -1+i \\ ...
1
vote
0answers
141 views

Positive integrand giving negative answer

I'm integrating a positive function f(t) times sin(t) from 0 to pi/5 and get -38. Actually f is slightly negative for a short time (smallest value ~ -0.0005), but far from enough to explain this. ...
6
votes
3answers
270 views

ListPolarPlot not showing full plot range even with PlotRange -> All

I have a list of data dpdOt (given below) with associated angular coordinates thetaplot, which when plotted using ...
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] ...
3
votes
1answer
121 views

Exporting large png results in completely black image

When trying to export an Image as PNG the resulting file is a completely black image. This happens only for certain images I have not been able to determine exactly ...
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 ...
2
votes
0answers
168 views

Derivatives of list elements

Could someone explain the odd behavior of the Derivative function when drawing arguments from lists? We have, ...
7
votes
2answers
253 views

Problem with NIntegrate when WorkingPrecision is specified

I am trying to evaluate this integral numerically: $$ \int_0^{\infty } m \exp (-m) J_1(m){}^2 \, dm $$ Everything is OK when only the integration method is specified: ...
3
votes
1answer
173 views

Sum of positive terms gives negative answer

Mathematica evaluates Sum[((n - y - 1)*(n - y)^2*n^y)/y!, {y, 0, n - 2}] as -2 e^n n. This should not be a negative value. ...
8
votes
2answers
338 views

Problem with ContourPlot3D

The following line works fine: ...
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 ...
3
votes
1answer
94 views

Discrepancy with TakeWhile between RandomInteger result and list on Linux

I have to following code that solves a problem for me. The example that is given to us is as follows: lst = {1,-2, 3, 4,5,-3, -4, 9,7,0,8}, predicate = ...
8
votes
0answers
177 views

Break[] inside ColorFunction

f[x_?NumericQ]:= (Do[Break[],{i,1,2}];x) Plot[x,{x,0,1},ColorFunction->(ColorData["Rainbow"][f[#]]&)] Break::nofwd: No enclosing For, While, or Do found ...
8
votes
1answer
310 views

LogPlot axes labels destroyed when working in high precision

(I'm using Mathematica 8.) I have a Taylor series: poly = Normal[Series[E^x, {x, 0, 10}]] I want to produce a log-linear plot of the error. This is easy enough ...
23
votes
0answers
519 views

What calendar is Mathematica using for dates in the distant past?

It appears that Mathematica treats all dates as proleptic Gregorian dates by default, a hypothesis that can be easily tested by using AbsoluteTime to compute the ...
4
votes
1answer
106 views

Strange behavior of DateList when converting string

DateList experiences some strange behavior which i cannot explain. This code works fine: ...
16
votes
2answers
647 views

How to compute the inverse CDF properly?

Note: this has been fixed in version 9. I want to compute the CDF and inverse CDF of the hyperbolic distribution: ...
2
votes
1answer
118 views

Using EdgeList on a once empty Graph crashes the kernel

Note: this is fixed in version 9. Calling EdgeList on a non-empty graph which was previously empty causes the math kernel to crash. For example, ...
9
votes
1answer
108 views

DateList not using current year when a year is not specified

According to the documentation when using DateList but not giving it a year it should use the current year. It is not doing that for me. Instead it uses 1900. ...
10
votes
1answer
180 views

Issue with PathGraph

I am having a strange issue with PathGraph. Executing PathGraph[{a, b, c}] or ...
6
votes
1answer
170 views

DistributeDefinitions not working for compiled functions

This is fixed in Mathematica 9.0.0. I'm having trouble with parallel evaluation of compiled functions. Here is a simple example illustrating the problem: ...
14
votes
1answer
304 views

Why does LogLinearPlot sample its argument outside the specified domain?

I experience a weird bug in the function LogLinearPlot. If the input is an interpolation function, such as the one created like this, ...
12
votes
1answer
165 views

NExpectation behaves oddly with EmpiricalDistribution

Note: this is fixed in version 9. My question concerns the usage of NExpectation and Expectation and why I see the behavior I ...
2
votes
1answer
157 views

VertexLabelStyle not found in Mathematica 8.0.0.0

I tried to use VertexLabelStyle, but seemed not recognized in my system with version number 8.0.0.0. Is this expected or I have missed something? From the online ...
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 ...
5
votes
1answer
136 views

Bug in LengthWhile?

Is this a bug or my MMA went insane or I'm missing something? LengthWhile[Reverse@IntegerDigits[1000], # == 0 &] works fine, but with SameQ instead of Equal, ...
10
votes
2answers
200 views

How to Write into multiple files?

Note: this is fixed in version 9. I want to put expressions into multiple files simultaneously, with the following code: ...
15
votes
1answer
669 views

How to export and import Graphs with additional data?

I'm trying to export and then later import graphs with additional data added such as VertexLabels and EdgeLabels. When I export ...