All Questions
93,899
questions
5
votes
1
answer
622
views
Use Pattern with Vectors in Assumptions
I had a problem using Pattern with Vectors in Assumptions.
Here's how I use ...
- 529
1
vote
1
answer
409
views
8
votes
2
answers
1k
views
Adjusting Density Plot Color Function for Diffraction Simulation
I'm trying to simulate Fraunhofer diffraction by a single slit using DensityPlot
I run the code:
...
- 491
16
votes
1
answer
1k
views
Ellipse counting from image
I have hundreds of images similar to this image:
I'm looking to count the number of ellipses as well as their major and minor diameters. The ellipses are touching, hence,
...
- 421
0
votes
1
answer
2k
views
Ellipsoid in spherical cordinates
I am trying to plot in spherical coordinates the ellipsoid defined as
$$(x/3a)^2+(y/2a)^2+(z/4c)^2=1$$
This is my code:
...
- 1
3
votes
0
answers
411
views
Exported PDF figure looks different in Apple's Preview than in Adobe PDF Reader
I'm trying to export figures into pdf, and the results looks good in Preview, but very bad in Adobe pdf reader. I'm using Mathematica version 8 on Mac 10.8.5. The Preview version is 6.0.1 (765.6) and ...
- 27.6k
1
vote
1
answer
115
views
Issues with creating functions [duplicate]
Sometimes when I try to create a function inside a function, Mathematica gives me a hard time. I usually just have to play around with the syntax until it gets something it "likes" but I really have ...
- 870
20
votes
9
answers
4k
views
Position of the first nonzero number
I want to know is there any one line code to find position of first nonzero number without calculating position of all non zero numbers. For example,
...
- 601
12
votes
4
answers
1k
views
How to replace every possible $A+B$ and $AB$ in expansion of $(A+B)^{10}-A^{10}-B^{10}$ with $x$ and $y$, respectively?
I would like to replace every possible $A+B$ and $AB$ in expansion of $(A+B)^{10}-A^{10}-B^{10}$ with
$x$ and $y$, respectively. How to do it with the simplest code in Mathematica?
For example,
\...
- 757
1
vote
1
answer
2k
views
Solve a total derivative - independent vs. dependent variables
I am trying to force mathematica to solve a generally defined function for d lp:
In a reduced version, w depends on l2, ...
- 103
0
votes
1
answer
103
views
Manipulate that remembers its own input code and can show it by request
This question is a further question to my previous one. The solution for that question works well as long as the original input Manipulate code is still provided in ...
- 1,429
12
votes
7
answers
8k
views
Filling a curve to a vertical axis
I am preparing a figure for an article, and I would like very much to be able to fill a curve, but not under it, but to the vertical axis, i.e. to the left. Due to the meaning of the data I present, I ...
- 519
3
votes
2
answers
469
views
Make fraction with selection in denominator
Using ctrl/ you can make a fraction. If you have selected something it will appear in the numerator.
Does there exist a shortcut to make the selected text appear in the denominator instead?
If not, ...
- 1,545
19
votes
9
answers
2k
views
0
votes
1
answer
181
views
How to make an index optional?
Can I define a relation between variables, such that the expression will also be evaluated (then assuming all indices are equal) when no index is given?
$$ x_i + y_j = \delta_{ij} \stackrel{...
- 101
1
vote
2
answers
1k
views
Row-Reduced-Echelon-Form with Equation Parameters for Consistent Systems
I often do row-reduced-echelon-form (RREF) calculations that involve parameters using the RowReduce command.
Most times, I want to know which parameters make the system consistent.
For example:
<...
- 1,075
4
votes
2
answers
1k
views
Find the value of parameter so that the equation has one solution
Let $(E_l) : x^4-4x^3+x^2(5-l^2)+4 x l^2-4l^2 = 0$ be an equation with $l$ as a parameter and $x$ as an unknown and $S_l$ the set containing all the real solutions of $(E_l)$.
Then there is a unique ...
- 2,529
4
votes
1
answer
121
views
Evaluate open cell segments in a notebook
The Evaluate > EvaluateNotebook evaluates the whole notebook.
Is it possible to somehow evaluate ONLY the open sections of a notebook?
- 2,158
2
votes
2
answers
2k
views
Coloring vertices using GraphPlot
I have the following problem: I used GraphPlot to plot my adjacency matrix.
I divided my nodes in three groups: ...
5
votes
1
answer
485
views
Is it possible to interact with an external program's command-line interface?
I am performing a calculation in Mathematica which relies on calls to an external program that acts as a black box for calculating a function $f$, and I would like to know if it is possible for ...
- 10.3k
2
votes
4
answers
3k
views
find the number of integral solutions a+b+c+d+e+f = 18 [duplicate]
Find the number of integral solutions of
a + b + c + d + e + f = 18
where a, b, c, d, e, f are elements of the range ...
- 21
2
votes
1
answer
451
views
How I can make a menu with different graphs with modifiable parameters?
I want a user friendly window in which to have a menu where you can choose the chart you want to display, in which you can move parameters in order to note the width or height of the chart, but I try ...
- 57
5
votes
1
answer
217
views
how to load everything when opening a saved notebook
generally, when I carry over work in a notebook from the previous day, I have to physically start from the top and re-evaluate every statement before I can begin from where i left off. Is there any ...
- 121
0
votes
1
answer
283
views
Workaround for automatic replacement of "\r" to "\n"
When I run the following code in an empty notebook
SetOptions[EvaluationNotebook[], testOption -> "\n\r"]
and then open the notebook in Notepad, I find
$...
- 6,438
4
votes
3
answers
592
views
Improve the performance of solutions to Project Euler (#14)
Problem
I have following code, when n<=10^5 it's not slow, but n>2*10^5 it's became very slow.
I think maybe some temp value greater than 2^31-1, so make compile invalid.
Could you give any idea ...
- 5,642
6
votes
2
answers
629
views
ParallelMap and Sow/Reap - not behaving as expected? [duplicate]
Is ParallelMap and Parallelize@Map expected to work with Sow and Reap construct.
This is a rather brief toy code to find all Primes just to force the use of Sow/Reap inside Map
...
- 2,158
5
votes
1
answer
382
views
PearsonChiSquareTest: set degrees of freedom
How to set degrees of freedom for PearsonChiSquareTest?
I have this:
...
- 153
5
votes
1
answer
288
views
Drawing a quadrangular surface
Is there a way to draw a quadrangular surface in Mathematica so that it shows the bilinear term (not two triangles)? The quadrangular polygon is given by the expression
$$\phi = \sum_i^4 N_i U_i$$
...
6
votes
1
answer
1k
views
How to define a button inside Manipulate that tells Mathematica to re-evaluate the whole Manipulate code?
I have written a Manipulate code carrying out some very complicated tasks. There is no problem for the first run, but if I click the reset button to reset all ...
- 1,429
6
votes
2
answers
2k
views
Merging Vertices of a Graph and adding up the edges weights
I have a Weighted Graph of g which looks like this.
...
- 1,235
4
votes
4
answers
235
views
How to get a list of pairs into the form $(x,y)$?
I want to put the solutions of the equation $y = (x + 3)/(x - 3)$, where $x$, $y$ are integers, into the form $(x,y)$. For example, $(2, -5)$ instead of $\{2,-5\}$. When I evaluated
...
- 4,503
0
votes
2
answers
900
views
Plotting problem
I was wondering why I keep receiving the error message
"Derivative should be a triple of numbers, or scaled form"
from the following code
...
- 1
4
votes
2
answers
195
views
How to optimize computing a product?
Problem description
Write a function to caculate the formula
My solutions
Solution 1:
...
- 625
4
votes
0
answers
117
views
Can I define a "postfix map" operator with comparable precedence behavior to // [duplicate]
I am trying to define a "postfix map" operator (denoted $OP$ for now) that behaves thus:
...
- 8,460
3
votes
4
answers
124
views
Check whether a function of two variables is a probabilty distribution function
I have a function like this
$f(x,y)=c\,y\,(y-x),\ \text{for}\ 0<x<2,\;-x<y<x$
and I need to find the value of $c$ such that $f(x,y)$ is a PDF.
How can I do that?
I know that the ...
- 133
0
votes
1
answer
311
views
Testing Equality Expression?
Even if in
Graph[{1 -> 2}] == Graph[{1 \[DirectedEdge] 2}]
the answer is True ; but why MMA doesn't show the result of the ...
- 1,235
1
vote
2
answers
205
views
Expression giving multiple plots of a function, where each plot varies according to the value for a certain parameter
How can I plot multiple plots for M = 10, 20, 50?
...
- 249
5
votes
1
answer
237
views
Looking to create a lesson on sensory perception of sound
I'm looking to show students a lesson on sensory perception, more specifically on masking. I know a little Mathematica but sound processing has evaded me.
I would like to create a white noise and ...
- 425
4
votes
4
answers
706
views
How can I make controls have Button-like behaviour?
The Button control is very easy to understand
Button["Press Me", Print["Pressed"]]
I press the button, I execute the function....
- 4,107
5
votes
3
answers
628
views
2
votes
1
answer
244
views
Input[] inside DynamicModule causing a kernel crash [duplicate]
I have those few lines of code causing a crash and I can't figure out why:
...
- 8,587
8
votes
5
answers
196
views
Expanding lists with split strings
I've got data of the type:
list = {"Class","MW","10 - 11"}
which I would like to split into a number of lists based on the number of characters in the second ...
- 19.7k
0
votes
1
answer
143
views
Evaluate outer function first
I'm new in Mathematica so this is maybe super easy to do, but I can't figure out how.
I've got a function plus[a,b] that sums two numbers and I need to implement a ...
- 111
7
votes
1
answer
376
views
RandomVariate does not fill range of PDF of distribution
I've declared my own probability distribution as follows
dist[a_, b_] := ProbabilityDistribution[Cos[(b x)/2]^2 Sinc[a x]^2, {x, -400, 400}];
When I try to ...
- 73
2
votes
0
answers
201
views
Equation Solving: Solution in terms of predefined functions
Is there a way that I can have Mathematica give me the solution of a problem it has solved in terms of functions that I have predefined?
The specific problem I'm trying to solve is:
...
- 121
13
votes
4
answers
734
views
How do you get a list of filenames from a URL?
How would I get a list of filenames available at a URL? For example, list the files at:
http://www1.ncdc.noaa.gov/pub/data/cmb/drought/weekly-palmers/2005/
- 4,107
8
votes
1
answer
243
views
FindSelectedFunction for packages - how to make it work?
Fixed in 10.0.
Works correctly since Mathematica 10.0.
The Mathematica help menu contains an entry Find Selected Function (Cmd+Shift+F on OSX).
If you are working with say ...
- 8,722
0
votes
0
answers
37
views
Solving an algebraic equation with one or more constraints? [duplicate]
Just as a simple example, say I wanted to solve Sin[x] == a for x with the constraints -1<=a<=1 and 0 < x < Pi. Is there any way to do this?
- 101
0
votes
0
answers
220
views
How to improve the quality of 3D rendering? [duplicate]
I am trying to combine various 3D objects for a composite image. But some of the objects just don't look very good. In the end, I want to have a publication-quality image.
For example, here I ...
- 68.4k
4
votes
0
answers
197
views
MathKernel with `-noprompt` hangs indefinitely when converting simple TeX expression
If I enter
MathKernel -noprompt -run 'ToExpression["1", TeXForm]; Exit[]'
the kernel hangs, apparently while running TeX.exe ...
- 250