1
vote
3answers
176 views

How to calculate time period?

I have the starting and ending dates and times. And I need to calculate the night time in this period (from 10 pm (22) to 6 am (6)). Example: starting date and time is {2015, 1, 4, 3, 10} ending date ...
2
votes
1answer
186 views
1
vote
2answers
96 views

Is there a way to search for Arithmetic Progressions in a list?

If you have a list of integers is there a way of searching that list to see if there is a trend of Ax+B in the list? Not using all of the numbers, just seeing what trends like that are embedded in a ...
1
vote
1answer
66 views

Convert Dates to values on an X axis

I have a bunch of dates and values which I put into the DateListPlot to get a graph. However I would also like to put this information into the Fit or LeastSquares to estimate what the value would be ...
4
votes
3answers
207 views

How to highlight the elements in a list that match a pattern?

For example, {{1,2,3},{1,2,3,1,2,3,4,5}}with pattern {1,_,3}is transformed to ...
1
vote
0answers
129 views

How can I speed up this NM optimization? Most delay seems to be due to long analytic expression

I am struggling with computational speed of a NelderMead optimization. Nevertheless my impression is that I lose lots of speed not only due to the NM optimization itself but rather to for instance ...
5
votes
1answer
166 views

Integration over a convex combination of a region: $\int_{\Omega} (w_1 z_1 + w_2 z_2)^{1-\sigma} d (z_1, z_2)$ where $\Omega = \{ z_1 + z_2 = 1\}$

Take $w,z\in R^{n}$. I am interested in integrating (as generically if possible) $$\int_{\Omega}(w \cdot z)^{1-\sigma} d z$$ Where the domain of $\Omega$ is $1$ dimension, and includes the convex ...
3
votes
1answer
258 views

Package autoloading not working in CDF and Player Pro

I have made a package BeginPackage["top`"] t[x_]:=MessageDialog["This is top"] t1[x_]:=MessageDialog["This is top1"] EndPackage[] and used the code of this ...
0
votes
3answers
81 views

How do I integrate this function?

I am very new to mathematica and also new to this community. I have a problem given below, How to express this in Mathematica? $H=[2,4,10,5,12,34,42,\cdots 12]$ is a vector of size $N$. $h_n$ is the ...
4
votes
2answers
70 views

conditional expectation doesn't work with SmoothKernelDistribution

I'm trying to calculate a conditional expectation E[ x | x > a ], where the distribution of x is inferred from a finite ...
6
votes
4answers
325 views

What is shorthand way of Reap list that may be empty because of zero Sow

Sometimes because of conditionals, you cannot guarantee that Sow will be called at least once. Reap[Sow[1]][[2,1]] results in ...
2
votes
1answer
246 views

Is there a way to simplify a symbolic expression at assignment, once-for-all?

I have a series of symbolic function calls that could be greatly simplified using some assumptions. I think I would like for these assumptions to be used in the definition of the function so that they ...
2
votes
1answer
109 views

What is “ (Dialog) Input [ ] := ” after evaluating a cell?

I have done a time-consuming run and calculation. After many hours ( about 7 hours!), the black color which shows that the cell is evaluating, turn into gray and a strange text appears like this : ...
0
votes
1answer
136 views

Plotting with arbitrary units

I would like to plot, say, Sin[x/a] with multiples "a" showing on the x axis as units. How can I do that ? I have tried setting the plot limits e.g. {x, -2a, 2a}. I cannot plot said function even ...
4
votes
1answer
1k views

Lie-Bracket of two vector fields

I'm new to Mathematica (installed couple of hours ago) and I need to compute a few Lie brackets between two vector fields $f$ and $g$. $$ f\left(\mathbf{x}\right) = \left( \begin{array}{c} ...
-1
votes
1answer
55 views

It is possible to calculate a two vector integral

I have this problem: calculate the integral of: -1+Sqrt[2*d+1] with d being a distance of two points in a 60$\times$60 box ...
6
votes
3answers
116 views

Comparing elements of a set and deleting elements based on a criterion

I have a function that has two inputs. The first input is a set of 2-element sets, and the second input is a single 2-element set. My function complements each 2-element set with the second ...
18
votes
7answers
867 views

How to use Union on list of lists without sorting them first?

If I do ClearAll[a, d] lsts = {{a, d}, {a, d}}; Union[lsts] I get the expected answer {{a, d}} but if I do ...
0
votes
0answers
39 views

Procedure argument value change [duplicate]

I'm trying to create my own hamiltonian cycle algorithm using Mathematica for school, and I'm stuck on a syntax issue. I get the following error: ...
1
vote
3answers
162 views

Find value of x such that x! less than or equal to 1000

I am trying to find the maximum value of $x$ such that $x! \leq 1000$. I tried the following: NSolve[Factorial[x] - 1000 == 0, x] but I got this message: ...
1
vote
3answers
68 views

Delete permutations of subtables in a table [closed]

I've got a table of tables: $A=\{\{a,b\},\{b,a\},...,\{a,b,c,d,e\},\{e,d,c,a,b\},...\}$. How do I do to remove backward duplicates, or more generally permutations of duplicates in the table? For ...
0
votes
1answer
53 views

Create a Table depending of two variables [closed]

I tried to create a table depending of two variables as: W= Table[{G[[i]], G[[j]]}, {i, 1, 3}, {j, 1, 3}] I wanted it to look like ...
2
votes
1answer
368 views

Place legend without border above the plot

I use Mathematica 7.0 and as far as I know, there is not method PlotLegends, only PlotLegend. I want to set my legend - without background, shadow and frame - above my plot, as in the example belowe: ...
0
votes
0answers
39 views

How to use FindFit to find the parameter in Laplace space(numerically inverting Laplace transforms)

I am trying to find the parameter in Laplace space, and a very simple example is shown below: I have known the solution $y_{laplace}$ in the laplace space is $a/s^2$, and I also have some discrete ...
0
votes
1answer
140 views

How to obtain Laurent series coefficients of an (almost) arbitrary function?

I have observed that Series in Mathematica assumes that the given function is smooth in the point around which one wants to perform series expansion. For instance: ...
4
votes
3answers
187 views

Periodically tiling a function

I have a function which creates a hole of varying radius, depth and would like to tile it in x and y. ...
22
votes
0answers
514 views

What is the status of `::usage` and Templates in Mathematica v10.1?

In Mathematica 9, a number of issues concerning the ::usage and templates were raised. In 9.0, there was a bug first reported here and better diagnosed here, where ...
-1
votes
1answer
107 views

Using InterpolatingFunction in equations

I tried to use InterpolatingFunction in another ODE, but it doesn't work, because it seems for Mathematica that 2 functions are unknown instead of one. ...
0
votes
1answer
68 views

Block Matrix Multiplication [closed]

I have a = {{-1}, {0}, {0}} b = IdentityMatrix[3] c = {a, b} d = {{7}, {2}, {0}, {0}} and would like to compute e = c.d ...
0
votes
1answer
53 views
0
votes
0answers
63 views

Strange “Collect[…]” behaviour

I have a large expression which I need to simplify by pulling out a load of constant terms. Collecting terms seems to only work when the expression is expanded out, e.g. ...
1
vote
2answers
166 views

Limit the number of processors used by ParallelTable?

By default, ParallelTable will use all the processors available in a PC. Is there a way to set a limit to the number of processors used by ...
4
votes
1answer
70 views

? (Definition) versus ?? (Information)

What is the difference between ? Definition and ?? ...
0
votes
1answer
111 views

Generate the conference badge

I have a list of about 50 conference attendees with 3 columns (First name, Last name, University). I would like to use Mathematica to generate the conference badge for each people. The badge dimension ...
0
votes
1answer
94 views

Finding the intersection of two graphs [duplicate]

I'm having difficulty with finding the intersecting point of two graphs. Here is what I have done so far: Plot[{8*n^2, 64*n*Log2[n]}, {n, 0, 100}] which produces ...
22
votes
2answers
641 views

What is the difference between Composition (@*) and sequential applications (@)?

What is the difference between f@*g@*h@x and f@g@h@x Both evaluate to f[g[h[x]]] ...
0
votes
2answers
163 views

Numerical 3D Integration in Mathematica [closed]

My question in short is: Is it possible to make numerical 3D integration in mathematica efficiently? Or am I gonna have to move this to C++? I feel this problem is way too trivial to go to C++, so ...
5
votes
2answers
196 views

How to make a world map with a coloured ocean and transparent land surface?

I'd like to make a world map with a blue coloured ocean and transparent land surface (to be used later as an overlay). With: ...
4
votes
1answer
171 views

What is “MouseDragged”?

Maybe I'm picky but I don't consider static pressed button: "dragging". EventHandler[Framed[1], {"MouseDragged" :> (Print@RandomReal[])}] neither does ...
14
votes
3answers
2k views

Finding a Concave Hull

I have a 3d clustered data: Is there any other way to get concavehull of 3D data points?
2
votes
3answers
104 views

How do I map a function onto the result of an expression that already has a pure function as an argument

I admit that I have only a basic understanding of the way Mathematica handles pure functions - enough to be dangerous, unfortunately. I have some data that is in a list of lists of lists. I would ...
2
votes
1answer
67 views

Is there a shorthand for Optional with Condition?

I have a recursive function that does some work to an object for a repeatedamount of times. ...
1
vote
0answers
245 views

SystemException[MemoryAllocationFailure] with Memoized function [closed]

Version 10.1 Win7x64 Enterprise. This is more of a report than a question but others may have seen the same / have insights. I have some code (that I can't really post as it's too big) with a large ...
1
vote
1answer
116 views

Plot roots of polynomial system of equations in 3 variables

I have the two equations $x^2 + 2y^2 + z^2 = 1$ and $xz -y^2 = 0$ I want to plot the roots in 3D. i.e the coordinates $x,y$ znd $z$
2
votes
3answers
138 views

DeleteDuplicates in a list of 2-tuples under condition

Having a list of 2-tuples, I would like to delete such 2-tuples that have 0 at second position, but only those, whose first element is not unique in the list. E.g. ...
1
vote
0answers
58 views

Improving RationalInterpolation Result

The following code produces a {4,4} rational interpolation approximation accurate to 10^-6 or better over the range ...
3
votes
1answer
243 views

Region bounded by Ellipse and Line

I have an ellipse defined either as algebraic or geometric: algebraic: ax^2 + bxy +cy^2 + dx +ey +f = 0 geometric: major Axis, minor Axis, x center, y center, ...
0
votes
1answer
106 views

Difference between Log and Log10 [closed]

I typed a function : f := Tan[(1/a)*Log[(Sqrt[x^2 + y^2])]] - y/x I assigned values: ...
27
votes
2answers
2k views

What are the cool kids talking about when they use ##&[]? [duplicate]

All the cool kids are apparently using ##&[] for Unevaluated @ Sequence[] but I have no idea what either means. ...

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