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4
votes
0answers
118 views

Error with String patterns producing Removed[“$$Failure”]

While working on How to capitalize the first letter of each word in a string and trying to understand why certain characters were not considered letters I tried this: ...
20
votes
7answers
3k views

How to capitalize the first letter of each word in a string

The following examples only work for the first character of the whole string, but not of words. ...
4
votes
1answer
311 views

Can't simplify Abs[a*Cos[x]]^2

Why doesn't FullSimplify[ Abs[a*Cos[x]]^2, Assumptions -> {{a, x} ∈ Reals}] simplify to (a*Cos[x])^2 but this query <...
3
votes
1answer
445 views

NDSolve: Reinitialize fails with If condition

I have found a weird problem using If conditions containing an state inequality of the form state<=. First consider the simple ODE with an If condition ...
13
votes
1answer
344 views

Possible bug with second argument of Dynamic

Bug introduced in V9 or earlier and fixed in V10 According to the documentation, Dynamic Details & Options section, especially: For interactive mouse operations ...
13
votes
3answers
2k views

How can I convert colors to grayscale?

I want to change the above colored plot into a grayscale plot. I have tried this: CCGray[pic_?ImageQ] := Module[{}, ColorConvert[pic, "GrayScale"]]; but it doesn'...
0
votes
1answer
531 views

Parallelize matrix operations

I'm trying to reduce to a minimum the time of some matrix operations. When I don't parallelize and write the code in the most compact form I get the operation done in around 1sec (is this good? the ...
0
votes
2answers
126 views

How to add a condition to a formula so that it will not appear at the result? [duplicate]

Sometimes I have very long and complicated equations, when I evaulate the equations for example taking derivative or integral there will be several conditions with the answer. My question is that; is ...
25
votes
2answers
9k views

Measuring execution time of code

How one can measure the execution time (time that is spent for code to finish) of a program in Mathematica? I understand that there are general timing functions (Timing, AbsoluteTiming, TimeUsed, etc....
2
votes
0answers
516 views

Controlling page breaks

I'm writing a bunch of cells to a new notebook nb and am trying to control the pagebreaks. That is, I want a pagebreak after each Length[listOef] number of cells. ...
1
vote
1answer
217 views

Locator with Integer value coordinates [duplicate]

I want to get the Pixel value of an image.and here is my code ...
11
votes
5answers
2k views

Relational joining of tables

A common thing to want to do with data is to combine it (at least I thought this was a common thing). In SQL there is the idea of table joins "select id,v1,v2 from A,B where A.id=B.id" kind of thing. ...
1
vote
1answer
593 views

Using NMinimize Properly

I'd like to find the point on a Bezier curve that's closest to some other point. The tricky thing is that because Bezier curves can loop around, the distance function can have multiple local minima ...
3
votes
1answer
77 views

Delete `x,y,z` occurrence (or any permutation of it) from parent data set (dynamically)?

Simple question: I would like to dynamically specify a list of 3 elements, {x,y,z}. Then I'd like to find that list, or any of its permutations, in a parent data ...
3
votes
2answers
1k views

Quadratic programming problem

I am trying to solve a (Sequence) Quadratic Programming (SQP) problem in Mathematica. Here’s the problem setup: ...
3
votes
1answer
208 views

DirectAgglomerate not working for Large Matrices

I am trying to graphically display a distance matrix with similar elements visually clustered into groups. My original matrix has the elements in a random order so the first thing I do is to change ...
23
votes
2answers
601 views

The dangers of SaveDefinitions — should this really happen?

I have been bitten hard by SaveDefinitions -> True. I'll describe in detail what happened below. My questions are: Is this a bug? What is the most convenient ...
53
votes
2answers
4k views

Image segmentation and object separation in 3D using Mathematica

I currently work on an image segmentation scenario to detect cell nuclei in 3D using Mathematica. The data I have are image stacks in the TIFF file format. I would like to keep the sequence of image ...
8
votes
3answers
1k views

Poor quality Rasterize output when Background -> None

I am attempting to generate partially transparent images for PNG Export, but seem to run to the following issue. If I Rasterize ...
17
votes
4answers
12k views

Turn expression into function

I'm new to Mathematica and I spent the last hour trying to make the expression ...
3
votes
4answers
359 views

Wrapping grid with dynamic

I'm trying to build a sortable grid: ...
3
votes
0answers
454 views

How to prevent simplification of hypergeometric functions resulting from integrations?

Definite integrals from 0 to Infinity over a product of two hypergeometric (including exponential, trigonometric, hyperbolic, ...
0
votes
0answers
65 views

Simplify symbolic expression in terms of constants [duplicate]

Say I have an expression $a+b+a\times b$ and I define $c:= a\times b$. How do I get Mathematica to write $a+b+a\times b$ in terms of $c$, i.e. $a+b+c$?
2
votes
1answer
652 views

Print indexed (by subscript) variable name systematically

I have some variables : Subscript[S, 1], Subscript[S, 2]...etc. But they are defined in a for loop like For[g = 1, g < 4, g++, Subscript[S, g] = g]; Later, I ...
26
votes
3answers
1k views

Efficient priority queues?

I'm trying to figure out how to transfer the concept of a priority queue to the functional world. Searches have turned up some implementations that use Append and other expense list copying techniques....
0
votes
1answer
296 views

fit recursive function to data

I have a function $g(x, n)$, which is a recursive expression: $x$ is a variable and $n$ the number of iterations. In my case $n=3$ for all $x$. An example is the following: ...
7
votes
1answer
997 views

How to make dynamic input fields work with drag & drop

I have an application using InputField to allow a user to dynamically update a data structure. In some cases the user will want to remove a string from one field ...
6
votes
1answer
879 views

How can I highlight and individually color the connected components of a graph?

I have a graph G, and I wish to individually highlight and color the different connected components of a graph. It is simple enough to do this for one component: <...
2
votes
1answer
134 views

Append CellTag to list of Cells

As suggested in this earlier post, I restate my question here about appending CellTags option to existing list of Cells. What I ...
-1
votes
1answer
218 views

Linking two differential equations

The solution and plot of the Differential equation is $\frac{d^2S(r)}{dr^2}+\frac{1}{r}\frac{dS(r)}{dr}-S(r)+3S^3(r)=0$ ...
1
vote
1answer
160 views

SetOptions and Cell

I'm trying to change the CellLabel of Cells using SetOptions[Cell, CellLabel -> "test"] or ...
30
votes
4answers
4k views

Show density plot on a geographic map

I have a bunch of data points in the form of {latitude, longitude}. How can I plot their density on a US map? Single points on the map do not clearly show their ...
3
votes
1answer
169 views

Why the EuclideanDistance of these 2 exact points generates the warning N::meprec?

The two points are: pts = {{1/4 (-1 - Sqrt[5]), Sqrt[5/8 - Sqrt[5]/8]}, {1/4 (-1 - Sqrt[5]), -Sqrt[5/8 - Sqrt[5]/8]}}; EuclideanDistance @@ pts N::...
5
votes
1answer
156 views

How can I execute a sequence of statements interactively?

I'm fairly new to Mathematica. Suppose I have the following function: f[x_Integer] := Module[{y, z, r}, y = 5; z = 10; r = x + y + z; r ]; and I ...
12
votes
3answers
866 views

WaveletScalogram in polar coordinates

For given dataset data = Re[Zeta[1/2 + I Range[0, 100, 0.01]]]; It is nice that Mathematica can plot data in both Cartesian and Polar coordinates. ...
2
votes
1answer
283 views

Change values in string under condition

how to change the width and height in the HTML code into some other values decided by ratio and a fixed width? The background is that you can adjust a image in ...
1
vote
2answers
116 views

HoldForm and RandomChoice

I'm trying to get random expressions displaying. For that, I'm starting with addition, multiplication, substraction and division. When trying out this code ...
20
votes
3answers
7k views

Implementing a dictionary data structure

As one learns from a course on data structures, hash maps or dictionaries can be efficient when applied to appropriate tasks. I need a hash map in Mathematica and I've never found it. I'm scratching ...
1
vote
1answer
292 views

Need better font control [duplicate]

Generally many programs have a menu item to raise/lower current font size. This is much more convenient than trying to root around in in internal mathematica options. I need to change ALL default ...
43
votes
1answer
954 views

Do Mathematica notebooks include personal metadata?

I am about to send a Mathematica notebook to someone and I would like to make sure it does not contain any information that could personally identify me. I would also like to produce pdf files from ...
4
votes
0answers
819 views

Clearing memory of a subkernel in a Do loop

I have a Do loop, which saves data directly to a .txt file. However when I leave it running for long periods of time the RAM ...
0
votes
2answers
394 views

LogPlot of the calculated data in For Loop in Mathematica

I have the following loop, for calculating a data for different values of inputs. How I can plot the result at the end of For loop? Its not matter if the plot is inside or outside the loop, I just ...
-2
votes
1answer
3k views

plotting the solutions of system of differential equations [duplicate]

The following code include the system of differential equations: ...
2
votes
1answer
140 views

Strange response with dynamic texture and MousePosition

I built a cubic, then use MousePosition together with GUIScreenShot to take a floating region with fixed size (200*200) on the ...
2
votes
2answers
130 views

How to make a function work on symbols in a specific context

Let us say we have two sets of symbols $(x, y, z)$ with the same names that live in two different contexts: ...
5
votes
3answers
1k views

SparseArray row operations

Given a large (very) sparse matrix, A, how can I efficiently "operate" on only the nonzeros in a given row? For example: For each row in A, generate a list of column indices that have a magnitude (...
6
votes
6answers
481 views

Sort a list of coordinates by frequency from first component of each coordinate

The situation is that I have a List like this: ...
-1
votes
1answer
162 views

Indicating the axes [closed]

I want to scale the $x$ axis of the plot by $x^0$ and the $y$ axis by $\tan x$. Is this possible ? Plot[Tan[x], {x, 0, 10}, PlotRange -> Automatic] EDIT: ...
45
votes
1answer
10k views

How to visualize Riemann surfaces?

In WolframAlpha we can easily visualize Riemann surfaces of arbitrary functions, can we plot the Riemann surface of an arbitrary function using Mathematica and ...
1
vote
1answer
267 views

Do any users know of methods to capture Twitter feeds and subject them to analysis? [duplicate]

I would like to use the output of about 300 Twitter sources and would probably collect 30 minutes of tweets at a time and subject each collection to analysis; ideally this process would be automatic ...

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