Tagged Questions
2
votes
0answers
88 views
Derivatives of list elements
Could someone explain the odd behavior of the Derivative function when drawing arguments from lists? We have,
...
8
votes
2answers
132 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
124 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
175 views
3
votes
0answers
75 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
79 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 = ...
6
votes
0answers
111 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 ...
21
votes
0answers
383 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
78 views
Strange behavior of DateList when converting string
DateList experiences some strange behavior which i cannot explain.
This code works fine:
...
9
votes
1answer
100 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
169 views
Issue with PathGraph
I am having a strange issue with PathGraph. Executing
PathGraph[{a, b, c}]
or ...
6
votes
1answer
147 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
214 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,
...
2
votes
1answer
140 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
155 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
124 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, ...
