All Questions
92,297
questions
0
votes
0
answers
36
views
The Value is not Updated in the list/table [closed]
I have following data
groupedTerms3rdcycle = GroupBy[term3rdcyclelist, Most -> Last];
where term3rdcyclelist is the list.
I ...
- 123
0
votes
0
answers
55
views
Can Manipulate's execution result be represented by In&Out Cell?
I wrote the following code.
...
- 1,522
3
votes
2
answers
229
views
Contourplot with three variables
I have the following equation to generate a contour plot for it:
ContourPlot[{(6 x^2 (-0.00001 + (z)^2))/(6 y^2) == 0.2}, {x, -1, 1}, {y, 0.1, 20}]
It has three ...
- 361
3
votes
2
answers
143
views
Taylor approximation of integrals
I have BVP as in the picture and I want to solve it numerically by method given as follow. In the original paper, it is motioned that first iteration is computed and other are computed with Taylor ...
- 83
0
votes
2
answers
57
views
Automatic FrameTicks with MaTeX style
I'm currently working on generating several function plots and have been using the following code as a template:
...
- 491
1
vote
1
answer
103
views
Using Reduce to simplify (not solve) system of equations
I'm dealing with a Mathematica program that generates a set of coupled non-linear equations involving an unknown function and its derivatives with respect to at least one independent variable. My goal ...
1
vote
2
answers
105
views
Normalized Coincident Detection Probability of Laguerre - Gaussian Modes
I am working on a paper in which a pump mode is passing through SPDC(Spontaneous Parametric Down conversion) is converted into two photons called as signal and idler. In which laguerre-Gaussian mode ...
- 23
2
votes
3
answers
172
views
Manipulate list of equations
I have a list of equations:
eqns={a/b==c,d/e==f,...,x/y==z}
Now I want to muliply each of the equations with corresponding denominator, so that the result is:
<...
- 39
0
votes
1
answer
49
views
Sigma Delta Modulator in Mathematica
Below code is for 1st order sigma delta modulator used in ADC/DAC circuits.
...
- 41
3
votes
3
answers
138
views
FunctionContinuous for a function defined with Which
The function:
f[x_] := Which[0 <= x < 1/2, x^2, 1/2 <= x <= 1, x^2 + (x - 1/2)^3];
is continuous on the interval $0 \leq x \leq 1$, as a simple ...
- 39.9k
1
vote
1
answer
53
views
Selecting regions from the screen to capture dynamically
I know that by using CurrentScreenImage with some coordinates that I can capture regions of my screen. I would like to be able to capture a rectangular region of my ...
- 1,822
5
votes
3
answers
86
views
How to add a column to a dataset made up of an association of associations?
A dataset can be created in at least two ways: first, from a list of associations, second, from an association of associations (I know that it is also possible to create it as a list of list and an ...
7
votes
7
answers
427
views
Accumulated instance count of each list element
Given a list with repeated elements, for example:
list = {m, i, s, s, i, s, s, i, p, p, i}
I'd like to determine, for each position in the list, how many times the ...
- 1,325
0
votes
1
answer
53
views
How can I add a point label to this plot? [closed]
I am using the listlineplot function. How do I label a specific point with text?
0
votes
1
answer
50
views
Adding an empty circle to this plot, plus changing styles
I cannot find a god solution to highlight the intersection point between these two curves, in the plot I made:
...
- 779
0
votes
0
answers
64
views
Help implementing Lagrange inversion
I'm attempting to find the coefficients of generating functions using Lagrange inversion. I am finding the series coefficients with:
...
2
votes
2
answers
230
views
The center of mass of a semiellipsoid
I am trying to find the center of mass of a semiellipsoid using cylindrical coordinates.
r^2/a^2+z^2/b^2 < 1, z < 0 the density = 1.
I know that the center of mass is (1/M int,int,int rcos(theta)...
- 31
0
votes
0
answers
34
views
Why do plots change in dependence on sample order?
I suggest two identical data set dat1 and dat2, save the order
of samples is different.
After selecting the first or the second data,
the SCORE and LOADING plots are different.
This seems to be in ...
0
votes
0
answers
63
views
Determining special intersection points from 3D points defining a surface
I need to calculate a complicated integral. I asked a question:
Method to compute this integral, but my question has been closed.
First of all, I need to get the domain of integration.
I have a ...
- 193
5
votes
2
answers
141
views
Minimum/optimal number of tiles to cover all boxes
I have been struggling with the following problem.
Given:
the coordinates of a bunch of boxes/rectangles (in the form {xmin,ymin,xmax,ymax}) aligned with the x-y ...
- 5,997
4
votes
1
answer
309
views
How to make a polynomial so that f(i) = 1/(2^i)?
I know that, sequence has formula $f(n) = \dfrac{1}{2^n}$ satifying the conditions $f(1)=\dfrac{1}{2}$, $f(2)=\dfrac{1}{4}$, $f(3)=\dfrac{1}{8}$, $f(4)=\dfrac{1}{16}$. Now I am trying to find a ...
- 697
1
vote
3
answers
99
views
Why does assuming f[_] > 0 does not work while Element[f[_], Reals] does?
Refine works with symbols in either way:
Refine[Sqrt[x^2], Element[x, Reals]]
(* Abs[x] *)
Refine[Sqrt[x^2], x > 0]
(* x *)
...
- 31
1
vote
1
answer
65
views
Extract boundary points of an interpolating function obtained by NDSolve
Given a set of coupled nonlinear equations I want to extract the boundary points that appears in the interpolation function obtained as an output to NDSolve function and then to define them directly ...
4
votes
2
answers
424
views
Largest integer between 1 and 1000 with no letter "n"
This problem is easy to solve logically - try it for fun if you want before you run the code and see the answer.
...
- 71.9k
1
vote
1
answer
70
views
1
vote
1
answer
40
views
Delayed rule at StringReplace
In the StringReplace example(chaging two letter to uppercase) below, delayed rule is used. However, the result is the same even if rule is used. 1)The delayed rule must be uesd in this case? 2)In what ...
- 399
3
votes
1
answer
92
views
Manipulate breaks when using the RegionFunction option?
For some reason, the code below breaks when using the regionfunction option with Manipulate. Am I missing something or is this a bug?
...
- 5,493
0
votes
1
answer
66
views
How do I copy what I enter into 'InputField' without any computational processing?
I made an InputField where I input the quoted sentences inside.
And I set InputField to copy every time I run it.
...
- 1,522
0
votes
0
answers
85
views
How to set the precision for the entire notebook
I want to do various computations conditional on a given precision for the entire notebook. I use the following code:
...
- 5,508
1
vote
0
answers
34
views
functional derivative with respect to the partial derivative of the metric with xAct
I want to compute the functional derivative with respect to a partial derivative of the metric with the mathematica package xAct.
This is what I have tried so far:
...
2
votes
1
answer
74
views
Rotating text in the Epilog of a plot results in distortion
I want to rotate text in a plot. When I rotate by 90 degrees, or 180, it's perfectly OK. But if I want to rotate to 60 or 45 degrees, then the text appears distorted (see example below). How can I fix ...
- 145
3
votes
1
answer
79
views
Nice output for FourierTransform
I want to demonstrate FourierTransform in a lecture. However if you give FourierTransform a differential equation it does not ...
- 16.1k
3
votes
4
answers
204
views
Different answers when attempting replacement of function argument
I have three function computing Fibonacci numbers which return correct answers when directly called with e.g. fib1[10]:
...
- 123
1
vote
0
answers
31
views
Monitor inside core function
I like DistanceMatrix: its performance is surprisingly high, even for a big data.
However, for a huge arrays and custom ...
- 1,197
3
votes
1
answer
124
views
Why does using a sparse matrix for least squares instead slow down the speed?
Here is the code. The matrix appears to be relatively sparse in terms of its visual representation, but why does using least squares result in significantly slower speed compared to the previously ...
- 111
0
votes
0
answers
23
views
Simplify vector calculus based on component splitting
I am interested in verifying a few Vector Calculus expressions using Mathematica.
These expressions are based on splitting a vector field into its transverse components (in the xy- plane) and ...
9
votes
5
answers
3k
views
Digits of Pi in colored spiral
In How to make the digits of π go around in a spiral like this?
it is described how to plot pi in a spiralform (in my case as binary number):
...
- 93
0
votes
1
answer
74
views
Which condition is better for WhenEvent?
I'm solving a non-linear system with NDSolve. See my previous post
In the WhenEvent, which one is better for ODE solving
...
- 41
2
votes
1
answer
89
views
MaTeX text looks shabby when latex generated pdf is not zoomed
I want to use Matex for the figures in my plots which I eventually would like to use in overleaf. I create a plot and use Matex in it and right click on it to save as pdf. I then use this pdf in ...
- 155
9
votes
0
answers
100
views
Searching AnatomyData efficiently
I really like AnatomyPlot3D, but find it exceedingly difficult to find Mathematica's terminology for an anatomical structure. Listing all of them and searching by ...
- 39.9k
2
votes
3
answers
372
views
How to handle units of measurement?
I'm trying to understand how Mathematica handles units of measurement.
That is I expect that a calculation should return a certain unit, but I don't succeed. Let's consider this example:
...
0
votes
0
answers
66
views
Maximizing a function that is only defined numerically
I have a function of multiple variables that is only defined numerically. I am trying to maximize the function and find the critical points as fucntions of two parameters p and s using FindRoot but I ...
- 1
8
votes
3
answers
138
views
Speed up this computation involving NSolve many times?
Can you think of a way of speeding up this computation ? I don't.
...
- 14.2k
0
votes
0
answers
36
views
Trouble implementing switching hybrid system with NDSolve
I'm trying to use NDSolve to simulate a hybrid nonlinear system that switches between different linear behaviors based on states and inputs (i.e. switching from one linear behavior to another) which ...
0
votes
0
answers
430
views
How to include impulses in differential equations?
I have two coupled differential equations as follows:
$$S'(t) = - \frac{a}{1 + B(t)} S(t),$$
$$B'(t) = \frac{c}{1 + S(t)} B(t) (1 - B(t)) - d B^2(t) \Big( \frac{1 - B(t)}{B(t)} \Big)^n,$$
where $a$, $...
- 73
0
votes
0
answers
41
views
Euler angles and WignerD, a question of signs
Express a 3D point as a linear combination of Spherical Harmonics, then rotate that point to a new position and find the new expansion in SH :
...
- 1,333
0
votes
0
answers
39
views
How to pattern match multivariate integral?
I have been using a pattern
Integrate[c_ f_, it:{x_Symbol, __}] :> c Integrate[f, it] /; FreeQ[c, x]
which matches an integral and pulls out c if c has no ...
- 83
2
votes
0
answers
40
views
Extracting tables from .pdf
Can we construct some automated method for extracting tables from pdfs?
I can get decently far by just copy and pasting its content and splitting at newlines but it would be great if it was possible ...
- 4,197
0
votes
2
answers
93
views
How to build the following region?
Consider a 3D figure defined by the dependence $\Delta x(z),\Delta y(z)$. One example is a pyramidal frustum, for which $\Delta x, \Delta y$ are linear functions of $z$, and $z$ lies inside the ...
- 4,701
7
votes
2
answers
355
views
