1
vote
0answers
128 views

Speeding up the numerical integration of a certain function

I'm using the following function f[t_] := 3/4 t^-3 NIntegrate[(x^4*Csch[x/2]^2), {x, 0, t}, Method -> {Automatic, "SymbolicProcessing" -> 0}]; I ...
3
votes
1answer
102 views

Using less memory to store and manipulate specific types

Is there a simple way to use Integer types (in particular, a table of Integer types) that require only 4 or 8 bytes (reps. 32 and 64 bits) representation? It seems that integers in Mathematica have a ...
1
vote
1answer
93 views

Why does one Monitor expression work while another fails?

I have a (somewhat involved) function f[x?NumericQ, y?NumericQ] and for some reason it behaves differently when given a Table ...
2
votes
1answer
302 views

plotting 3d points: z-axis is squashed [duplicate]

I am plotting 3D points and it occurs to me that Mathematica doesn't have an easy way to specify my points to be plotted in a uniformly scaled cartesian space. For example I plotted ...
1
vote
2answers
111 views

Using AddTo in a function

I want to create a function that will take a variable $x$ and reassign the value $x+2$ to $x$. So f[x_]:= x += 2 However: ...
6
votes
3answers
264 views

Converting expressions to “edges” for use in TreePlot, Graph

This question is similar to this: Nested list to graph. How to "flatten" an arbitrary expression, eg expr = a[b[c, d[e][f], g], h] to a list of key-value pairs ...
2
votes
0answers
107 views

Which functions automatically generate new functions?

In his video http://www.wolfram.com/broadcast/video.php?channel=362&video=1643, Wolfram gives the following example: the output from ...
1
vote
3answers
194 views

Binning events with weights

I have two vectors, one containing sampled energies and the other one for each of these energies a weight: e(i) and w(i). I ...
3
votes
4answers
709 views

How to find a path that traverses each edge of a graph exactly twice?

I have a question regarding a graph traversal problem. This is the graph I am working with: ...
0
votes
1answer
142 views

How to get correct numerical integration which should be zero? [duplicate]

I want to numerically integrate function berrycur over kx and ky. The definition of berrycur is given at the end of the ...
0
votes
2answers
93 views

Convert an expression from one form to another

I have this expression -0.433284-0.758719 x+0.00289158 x^2-0.443672 y+0.00149027 y^2 I want to express it in terms of ...
0
votes
1answer
75 views

strange result with trigonometric triple integral [duplicate]

I'm defining functions e[k_, t_] := Cos[Pi (k - 1) t] cosIntRaw[k_, l_, m_] := Integrate[e[k, t] e[l, t] e[m, t], {t, 0, 1}] cosInt[k_, l_, m_] := Assuming[Element[{k, l, m}, ...
1
vote
1answer
142 views

Probability Distribution of a Multivariate Hypergeometric distribution and maximum probability

Hello to all Mathematica Users! I have this question: Consider a box which contains 69 balls. 17 red, 1 white, 29 blue and 22 green balls. There will be picked 7 balls randomly, without putting the ...
2
votes
2answers
287 views

Delete pairs from a list

I have a data set in which I need to remove all matched pairs of entries - not just the first entry that is duplicated but both entries. To add to the complexity, the pairs must be between different ...
2
votes
2answers
109 views

Funny behavior of Ellipsoid function

From its description I thought that the normalizations of the directions d_i of the semi-axes did not matter when using the ...
5
votes
2answers
364 views

Why doesn't Roots work on a certain quartic polynomial equation?

In everything that follows I am using Roots to get the solutions to the equations. I start off with this equation: $$ \frac{A}{3}x^4 - x^2 + 2ax - b^2 = 0$$ Now ...
0
votes
1answer
59 views

How to check the decimal accuracy of result? [duplicate]

I am trying to check if the result is enough accurate to use. I need an accuracy of 10^-6 from some numerical method. Something like root finding algorithm. But how do I check that in mathematica? I ...
0
votes
0answers
32 views

Clear variables [duplicate]

I'm new in Mathematica and I am working with various notebooks. My problem is that when I run a notebook, it seems taking definitions from the previous notebook. For example in 'notebook1' I make an ...
1
vote
1answer
128 views

Unexpected result from FullSimplify

In the following simplification why doesn't Mathematica get a zero when asked to compute "Y-Z" eventually? ...
7
votes
3answers
282 views

String templating

I am pretty new to string processing in Mathematica. But I'm having some problems in doing simple string template filling to my mind elegantly. For example when doing export for my answer here, one of ...
11
votes
9answers
1k views

How can a power of 0 or 1 be replaced?

Consider this given example for ReplaceAll 1 + x^2 + x^4 /. x^p_ -> f[p] This returns ...
1
vote
2answers
137 views

How can I speed up the export of graphs in DIMACS format?

I'm creating random graphs with suitable properties and exporting them in the DIMACS format. Already, for rather small graphs with, say, ~60k vertices and ~240k edges, ...
2
votes
1answer
184 views

Factoring terms out of a polynomial

I don't do much algebra in Mathematica and was surprised to discover, while attempting to answer this question, that I had no idea how to factor out an expression from a polynomial. The question was, ...
6
votes
2answers
394 views

How to color separate a colored-in-pencil drawing?

I'd like to pick out just the "pencil" color in some drawings done by a young member of the household (he'd like to print out copies of these pictures and distribute them to his class mates on the ...
3
votes
1answer
103 views

Symbolic Output after numerical computation

I have a small question about the symbolic output. I started to write a program that generates the coordinates of n-dimensional polytopes by Wythoff construction. For crystallographic groups, all is ...
4
votes
3answers
387 views

How to use LineLegend and SwatchLegend together

I am wondering if one can place on the right of the plot frame a single legend that is a combination of a LineLegend and a SwatchLegend. What I want is to see the line with its label on top of the ...
11
votes
4answers
842 views

Is there a way to increase the smoothness of a cylinder?

I am using Cylinder to produce wide flat disks (in Mathematica 8). This works just fine except that the circular base of such a cylinder turns out to be really just ...
5
votes
1answer
235 views

More efficient Omnibus number determination?

Amusing myself with concepts from "Omnibus Sequences, Coupon Collection, and Missing Word Counts", in particular the sequences. To paraphrase the concept, a string is k-Omni over some alphabet a if ...
2
votes
1answer
69 views

How to joint symbolic expressions together [duplicate]

I want to joint symbolic expressions together to create a another symbolic expressions. one way to do that is as follows: ...
0
votes
0answers
115 views

A derivative encountered in matrix factorization using gradient descent

I want to factorize a matrix $a_{ij}$ as $$ a_{ij} = \sum_k u_{ik} v_{jk} $$ using variational method for some reason. That is, I want to minimize the cost function $$ F = \sum_{ij} b_{ij}^2 $$ with ...
0
votes
1answer
195 views

Why does show combined plots and graphics fail in CDF Player but not in Mathematica?

The question is, how might I get the following script working as a CDF demo of complex inversion in a circle? It works fine in my home edition of MMA 8 run on OS X Mavericks. When saved as a CDF file ...
7
votes
3answers
196 views

Circumnavigating a curve or going through it to show different behavior

I am not sure if what I want to do is possible in Mathematica. I've provided something simple below to convey what I want to do. Basically what I want to happen is that when the ...
2
votes
2answers
90 views

Using Table with arbitrary number of variables [duplicate]

Let $P=\{p_1,...p_n\}$. I would like a way to implent Table[Expression,{$p_1$,lim},{$p_2$,lim},...,{$p_n$,lim}] where n and lim are parameters defined by the user. Any ideas?
0
votes
1answer
77 views

Finding the right DeleteCases pattern for <<199>>

I have a list in Mathematica with several items like <<199>> and <<104>>, I would like to get rid of them using DeleteCases, but none of the patterns I ...
5
votes
2answers
125 views

Comparison Operation for Nested Matrices

I have a nested matrix n as bellow ...
4
votes
2answers
255 views

After executing MessageDialog[] how can I wait for it to close before continuing

After executing MessageDialog[] how can I wait for it to close before continuing? I want to popup up a message and wait for the user to hit OK before continuing. Is there a mechanism for this?
0
votes
1answer
2k views

wolfram mathematica intersection of two surfaces [duplicate]

I use wolfram mathematica. There is a function of two variables which defines the surface z = f(x,y), the second surface is defined as z = const. How to find the line of intersection of these two ...
2
votes
2answers
96 views

Creating function with matrix argument

I am completely new to programming, so I apologize in advance for a stupid question. I want to program an algorithm for computing invariant factors of a finitely generated abelian group, so in ...
4
votes
4answers
344 views

Defining a pure function involving a function argument

I've got an expression involving x and y that I want to use as a MeshFunction: ...
0
votes
0answers
32 views

Why I am not getting the same frequency when sampling a waveform? [duplicate]

I am trying to simulate the sampling of a waveform to then apply FFT Analysis to it. Here is the sample code I have now using a square wave: ...
7
votes
1answer
391 views

Smooth out contour in RegionPlot/ContourPlot

I would like to smooth out the jagged edges in the outermost contours in the following plot: I have data of values as a function of variables (x,y) in the form ...
6
votes
4answers
720 views

Exponential of a Differential Operator

In Mathematica, is it possible to exponentiate a differential operator such that the operator will act on a function, $f(x,p)$? Specifically, I wondering if I can get Mathematica to do this: ...
3
votes
5answers
2k views

A question regarding 1 divided 243

Here is a problem due to Feynman. If you take 1 divided by 243 you get 0.004115226337 .... It goes a little cockeyed after 559 when you're carrying out the decimal expansion, but it soon straightens ...
0
votes
1answer
171 views

Laplacian in D Dimensions

Is it possible to compute $\Delta F=\nabla^2 F$ for $F=F(x^1,x^2,…,x^D)$ with $D$ finite? I seem to be only able to specify spherical coorindates, for example, if I want to leave standard ...
1
vote
4answers
120 views

Drop row if sum of part of row is equal to zero

My problem is the following: Suppose I have a matrix A which looks the following: ...
0
votes
1answer
100 views

How to force Manipulate to use preserve control settings over successive evaluations

I have this Manipulate: Manipulate[Plot[Sin[a x], {x, 0, 2 Pi}], {a, 0, 3}] Now, I realize I had mistyped the expression and it's actually ...
34
votes
5answers
3k views

Fitting points to tilted, off-center ellipse

I have 24 x-y points that are supposed to form an ellipse. ...
2
votes
1answer
573 views

Rotation matrix $\to$ quaternion

I found a very good link about quaternions in Mathematica , but I don't know how to create a quaternion from a rotation matrix. Can anyone help me, please? Update I need this: A rotation may be ...
-1
votes
2answers
107 views

Strange numerical integration result

I write a function called berrycur[kx,ky] which I will give at the end of the question, and want to numerically integrate this function over {kx, -2π, 2π]}, {ky, 0, ...
1
vote
1answer
153 views

github api v3 repository create

I'm trying to create a github repository form a notebook, using this simple code ...

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