2
votes
1answer
185 views
3
votes
2answers
295 views

How do I find the best fit?

I am trying to solve following system of three differential equations ...
4
votes
1answer
104 views

Strange behavior of Mathematica regarding calculation time

Today I witnessed the following strange behavior of Mathematica, when it comes to calculation time involving larger nested lists. The following is the short example that I setup, I am sure one can ...
2
votes
2answers
154 views

Why doesn't the FileNameSetter button work in my DialogInput?

I am new to Mathematica, so it's probably a small error but I can't figure it out. Here is the code : ...
5
votes
1answer
229 views

Cropping an image to a minimum bounding box for a set of points

Imagine a define a pointlist inside of an image: Provided a pointlist for the set of red dots around the toy horse, is there a way for me to automatically crop to a minimum bounding box for this ...
1
vote
1answer
73 views

Why do two codes give different output?

I have tried the following to get the eigenvalues of several matrices of the type: ...
2
votes
3answers
290 views

Defining and isolating a region of an image internal to a bounding curve

I was recently looking over this very nice question by March Ho: Counting elements which are inside another element on a different colour channel There are often times where I find myself wanting to ...
1
vote
2answers
307 views

select subsets of elements of a list under a certain condition

I am new in Mathematica and am stuck on a simple problem. Please advise: I have the following list: list = { {"1", 1000}, {"2", 800}, {"3", 800} }; I want to ...
3
votes
0answers
149 views

List manipulation, replace a value [duplicate]

I have the following list: ...
10
votes
4answers
1k views

Axis/Angle from rotation matrix

With r=RotationMatrix[a,{x,y,z}] I can compute a 3D rotation matrix from axis/angle representation. Given a 3D rotation matrix ...
0
votes
1answer
156 views

Combination of a Contourplot and a Graphics Object

I want to combine the following to graphs. ...
3
votes
2answers
294 views

Color of a plane in Contourplot3D

I have the following code example: ...
2
votes
1answer
225 views

Compute Correlation between two binary variables

$X_1$ and $X_2$ are two binary stochastic variables with simultaneous probabilitydistribution: $$ \begin{matrix} &X_2=0&X_2=1\\ X_1=0&0.30&0.17\\ X_1=1&0.08&0.45 ...
4
votes
4answers
373 views

Listing matrices up to symmetry

I am interested in the equivalence relation on N x N binary matrices, in which two matrices are equivalent if one can be obtained by rotating/reflecting the other. I would like to obtain a list ...
1
vote
1answer
136 views

Value for x such that |(x-y)| is minimum

I have a list Y={y1,y2,y3,...,yn} And I would need to find x such that Abs[x-Y[[i]]] for all $y_i$ in $Y$ is minimum. ...
1
vote
1answer
155 views

Can I use SelectComponents with measurements that take into account the value of underlying pixels?

Normally, we can ask for the mean, median, etc. underlying pixel values for morphological components with the command: ...
1
vote
1answer
249 views

How can I solve my recursion equation?

How can I solve the recursion equation given below? I doubt there have no solution for the recursion equation because this is circulating recucrsion equation. ...
4
votes
1answer
348 views

Counting the number of operations performed during a calculation

I need to know how can I count the number of operations performed during a calculation of a CompoundExpression. In some of these expressions there are ...
4
votes
1answer
74 views

Constructing an Array from typed expression

I want to produce an array from expressions given by test[one][1] = 3; . . test[one][5] = 7; etc. Normally would use ...
2
votes
4answers
203 views

Removing coefficients and repeated elements

I got to a problem where as I just can't find the proper Mathematica command. I'm given a list, for example: $\{1,x1,-x1,x2,x5,x3,-x2,-x4\}$ I need this to become $\{1,x1,x2,x3,x4,x5\}$ The ...
0
votes
1answer
265 views

Pull Constants outside of integrals

I would like Mathematica to pull constants outside of an integral: e.g., $\int_0^t f[t] g[s] dt \to g[s] \int_0^t f[t] dt$ This has previously been discussed at replacement rule to pull independent ...
2
votes
1answer
117 views

Compact form for domain ranges of many variables

When one sets up an equation to solve one often needs to specify conditions on the variables such as { x>0 && y>0 && z>0 } This is not ...
3
votes
3answers
375 views

Constrain movement of a locator inside Manipulate

Once again a big thank you for the great help in my earlier post: Plotting function with Dynamic parameter. It totally worked out. I now have a new coding problem ...
2
votes
1answer
374 views

Crank-Nicolson with NDSolve?

As far as I understand, the Crank-Nicolson method (a.k.a. trapezoidal method) can be expressed as a second order implicit Runge-Kutta method. It's Butcher tableau is: ...
3
votes
1answer
140 views

LibraryLink Documentation

The documentation for LibraryLink has the following example ...
6
votes
1answer
153 views

Trouble with links to symbol pages generated by Wolfram Workbench

I am having some troubles with documentation generated by wolfram workbench. When i try to open symbol page created with workbench by pressing F1 I get a search page instead of my symbol page. When I ...
2
votes
0answers
77 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] ...
0
votes
2answers
110 views

Assigning several values inside DynamicModule

I have coded a model that contains several parameters. The parameters can be changed interactively by the user using an interface contained in a DynamicModule[]. There are several "basic states" of ...
3
votes
0answers
238 views

Weird behaviour from ListSurfacePlot3D

Looking at Documentation for ListSurfacePlot3D, I follow the basic example presented there. ...
3
votes
2answers
108 views

Zero order term in an exprerssion

I have a very long expression like a + b x/y + f + c y/x + d (x z)/y + ... where a , b, c, f ... are coefficients and ...
0
votes
3answers
353 views

Plotting function with Dynamic parameter

I'm trying to get this code working: a = 2; func[t_] := Dynamic[t + a]; Plot[func[t], {t, -5, 5}] The idea is: I'd like to have the dynamic parameter a change ...
8
votes
5answers
334 views

correct way to map a function on entries down the pages in a 3D matrix?

updated: added another method to the methods I tried below for completion. This is new way of doing it, but most likely not very efficient, did not time it I can only visualize 3D matrices in my ...
3
votes
1answer
72 views

Overscript distance

When I write: Overscript[PQ, \[RightVector]], the arrow is placed too close to the P and ...
1
vote
1answer
145 views

How can I use SelectComponents to select for components that have a pixel within a certain RGB range within their convex hull?

I calculate a set of morphological components: Components = MorphologicalComponents[Binarize[image,0.1]]; We can now use SelectComponents to filter for ...
5
votes
2answers
185 views

Can we compile using only Integers Of Unusual Size?

I coined Integers Of Unusual Size to mean "bignum" using GMP, the underpinning of Mathematica's ability to craft very big numbers. I have these functions from this question: ...
8
votes
1answer
350 views

Counting elements which are inside another element on a different colour channel

I have a 3-channel image which shows red and green points (certain labelled proteins) inside blue regions (cell nuclei). After applying some segmentation filters, the resulting image is as follows: ...
6
votes
1answer
190 views

Unable to save changes in Option Inspector from one session to another for the Documentation Center

I wanted to change the global option "WindowsSize" to the "large" value using the Option Inspector. It works well for the current session. But then I realize the "Apply" button was greyed and not ...
0
votes
2answers
79 views

Obtaining a particular form of solution for an integral

When I do: Integrate [E^(-(t/\[Tau])) Cos[\[Omega] t], {t, 0, \[Infinity]}] How could I get the solution in the form: ...
3
votes
2answers
203 views

How can I detect and modify one area of an image while preserving the rest

I have an image with a big black disk bounded by a white boundary in its center. The image contains some other stuff outside of the spot and its boundary. This stuff has colors which include both ...
3
votes
1answer
371 views

Tips for efficiently solving large system coupled (nonlinear) ODEs

I'm trying to solve a system of nonlinear, coupled ODEs, where the governing equation for the $n-th$ ODE is of the form: $\sum_k^M Q_{nk} \ddot{a}_k -\sum_{\ell}^M\sum_k^M S_n(\ell,k) \dot{a}_{\ell} ...
0
votes
1answer
183 views

Simplify function with normalized vector

I made a very simple case: testF[x_, y_, z_] = x^2 + y^2 + z^2 Simplify[testF[x, y, z]] If {x, y, z} is normalized, the simplified result should just be 1. How ...
2
votes
0answers
33 views

Plotting list-valued interpolating function [duplicate]

I have an interpolation function which returns a list, e.g.: f=Interpolation[{{1,{1,2,3}},{2,{4,5,6}}}]; When I try to plot it, I get single-colored curves. ...
5
votes
3answers
248 views
16
votes
1answer
302 views

How to strip all formatting from a string and convert it to plain text?

The documentation on String states: But if I try to perform some manipulations on this string, for example, take 2 words from the left, I get some shards of ...
2
votes
2answers
140 views

Conditioned Probability Task

I have this task with two questions I would like to compute in Mathematica. Suppose a pair of random variables $(X, Y)$ has a equal distribution on the following 7 points: $\begin{matrix} ...
3
votes
1answer
183 views

Converting this recursive function definition into nested sums?

Here's the recursive function I'm using: DH[n_, k_, s_] := Sum[Binomial[k, k - j] DH[n/m^j, k - j, m + 1], {m, s, n^(1/k)}, {j, 1, k}] DH[n_, 0, s_] := 1 Now, ...
-2
votes
1answer
376 views

Interpolating Function inside of NDSolve

I have a problem and it seems to be connected to an Interpolating function inside of an NDSolve command. The resistivity[x] ...
12
votes
0answers
855 views

Mathematica performance on Mac

I recently got a trial version of both Mathematica 9 and MATLAB 13a for Windows. I was stunned by the performance difference in the Windows and the Mac version. It was a simple test in matrix ...
2
votes
0answers
32 views

Detecting a more general pattern [duplicate]

I need a function that, given 2 patterns, determines if the first pattern is more general than the second (i.e. that any expression successfully matched by the second, will be successfully matched by ...
2
votes
3answers
193 views

Graph with $\{a,b\}$ as Vertex Instead of Number

I'm trying to create a graph which has $\{a,b\}$ as labels: ...

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