All Questions

0
votes
0answers
4 views

InstallR[] failing in Mathematica 12

I was trying to use R with Mathematica 12 tried these three commands, Needs["RLink`"] InstallR["RHomeLocation" -> "C:\Program Files\R\R-3.5.1", "Rversion" ->"3.5"] I am getting this error JLink'...
0
votes
0answers
10 views
1
vote
2answers
30 views

How to use the roots of equations

Can anyone explain to me how can I use the roots of an equation? Let clarify my question with one example. Suppose that I have an equation which I want to find its root: ...
5
votes
3answers
79 views

Could this problem be tackled using Mathematica?

I posted this question on Math, but there has been silence there since. So, I wonder if anyone here can get any closer to the answer to my question using Mathematica. Here is the question: Suppose I ...
0
votes
0answers
47 views

How to differentiate a function constructed through FindRoot?

I am trying to maximize a function which has as a variable another function that was solved numerically using FindRoot. My code is below.I start by defining some parameters ...
-1
votes
0answers
40 views

How to use Manipulate for protein sequence alignment?

so I have the sequence of a protein from Chain A and Chain B and I want to use manipulate to show what parts of sequence are identical.
4
votes
1answer
42 views

Variable dimensional integrals

I need to Integrate a function, but let the number of dimensions vary. Integrate[Product[Exp[-( t[[i]] )^2], {i,1,4}], options] ...
2
votes
1answer
33 views

Trouble with gambling function

I am trying to make a function which gives us a 1/7 chance of doubling up, or a 6/7 chance of losing $20. Each time the function runs should be an independent event. I have modeled it as follows: <...
2
votes
1answer
27 views

SequenceReplace is incorrectly modifying the list when a pattern partially matches

(Below is a big simplification of my actual use-case which reproduces the problem with SequenceReplace. Please assume my use of ...
0
votes
0answers
23 views

Sum over powers of roots of unity gives only partial answer

Mathematica seems to be unable to handle sums over roots of unity. For example, Simplify[Sum[Exp[2 Pi I a b/m], {a, m}], {b, m} \[Element] Integers] yields ...
0
votes
2answers
21 views

Checking if a system of linear equations admits a positive solution

How can I use Mathematica to check if a system of the form $A x > 0$ admits a solution $x\geq 0$ where $A$ is a $m \times n$ matrix and $x \in \mathbb{R}^n$. All inequalities are to be understood ...
0
votes
0answers
35 views

How to approach the following differential equation?

I obtained the following, apparently clean-looking differential equation, while solving a problem, but cannot find any efficient way to solve it analytically. The equation is of the form, $$[A - B\cos ...
4
votes
1answer
47 views

What is an example of of idiomatic “typed” WolframScript?

I'd like to make my own "typed function" in WolframScript. Suppose the type we desire is called money, and we'd like to make a function called ...
0
votes
0answers
17 views

Memory management with monitor or an alternative to monitor

I often use Monitor[...] to watch the progress and behavior when batch fitting a lot of spectra. Usually I have no problem with this at all, I typically may fit ...
0
votes
0answers
27 views

How to reduce large matrix to a multidimensional matrix?

I have a large matrix $h$ with dimension $N_x N_y\times N_x N_y $. it is related to matrix $a$ by this formula,where $i,i_1=1..N_x$ and $j,j_1=1..N_y$. ...
3
votes
1answer
26 views

Is there a limit to the amount of curated data that can be retrieved?

Mathematica provides access to curated data on many entities. For access to some of the curated data (e.g. current exchange rates), users must have an internet connection. Is there a limit (i.e. quota)...
5
votes
1answer
35 views

SparseArray: how to efficiently extract/delete many entries?

This is a follow-up of this question. We have a large $m\!\times\!n$ matrix stored as a SparseArray a and a list of positions pos...
0
votes
0answers
27 views

Function iteration

I wrote a function in Mathematica that applies certain construction steps on the "incidence matrix" of a graph in order to obtain a new graph with certain properties. These construction steps can be ...
2
votes
2answers
58 views

Evaluating FourierTransform like integral manually

I am trying to evaluate Integrate[x^2*Exp[I k (x - 1)], {k, -∞, ∞}, {x, -∞, ∞}] Since $\frac{1}{2\pi}\int_{-\infty}^{\infty} e^{ik(x-1)} d{k}$ is $\delta(x-1)$, ...
1
vote
1answer
27 views

Limit of an integral and hypergeometric function

I want to evaluate the following integral: Integrate[Sin[θ]^(D1 - Nc - 1)/(A Cos[θ] - I ϵ)^(N1 - Nc), {θ, 0, π}, Assumptions -> A > 0 && ϵ > 0] ...
-1
votes
1answer
39 views

How to specify resolution of a plot?

Suppose I need to plot Sin function: Plot[Sin[x ], {x, -10 , 10 }] Now I need to specify the resolution of the plot. I tried by using list Plot ...
0
votes
1answer
24 views

Plot region in between two discrete functions

I am trying to plot the region in between two curves that I only have as discrete data, without plotting the curves corresponding to the data. In principle, I could interpolate the functions and then ...
1
vote
0answers
13 views

Inverse fuction of TensorExpand

Is there a way in mathematica to factorize/simplify a dot product? I.e. I have something like a.b + a.c (obviously more complicated expressions) and I would like to factorize terms like ...
1
vote
1answer
27 views

How to get time series data from Entity[“Company”,…]?

In my notebook, I have a cell that displays AT&T's revenue for one particular year (the year 2010): ...
0
votes
0answers
14 views

WolframAlpha minimize multivariate function with respect to one variable and other parametrized problems

With WolframAlpha, how can I minimize a function with respect to one variable? For example, how can I get the solution $x^*= argmin_{x} x^2+xy = -y/m$? I always use hopefully sufficiently ...
1
vote
0answers
37 views

Boundary value problem for nonlinear ODE

I am trying to solve the following boundary value problem using mathematica v12: $$ (1-y) (1+(1-y) y q(y) (2+y q(y))) q^{\prime\prime}(y)-q(y)^2 (2-5 y+(2-3 y) y q(y))-2 (1-(1-y) q(y) (1-5 y+y (1-3 y)...
0
votes
0answers
30 views

FullSimplify does not simplify at all

I have some problems simplifying things with FullSimplify. Suppose a matrix ...
0
votes
2answers
34 views

Color coding points on spherical plot

I have a matrix with each element having two components. First component is an array of six elements, each of multiple of 1/6 but less than 1. Second component has two elements representing spherical ...
1
vote
1answer
54 views

Defining functions from strings

Blank symbol (_) is moved when applying ToExpression to the following string: ...
-2
votes
0answers
33 views

How to make panel in order to visualize diffrent color proteins?

I have 3 different plots of proteins and I want to display them, but what should I use, Manipulate, Dynamic Manipulate, etc. In the case for manipulate I also was thinking using viewpoint in order to ...
1
vote
1answer
37 views

Plotting points using multiple colors with `ListPlot`

I've got two sets of points, plotted with ListPLot. I would like the second set to have one point of each color specified. I've tried using ...
0
votes
0answers
36 views

How to generate a table of contents?

This answer is several years old and while the code still works I was wondering if there was any update from the community or Wolfram. The online references still point to AuthorTools which seems to ...
1
vote
1answer
53 views

How do I use Solve with conditional equations?

Short version: How do I have Solve handle a system of equations where some of the equations may be conditional? Simplified Problem: I am solving the following system of equations: a * b = 10^-14 b^...
0
votes
0answers
19 views

Finding nonzero points in a wide multidimensional space (but bounded)

I have a quite complicated region over 5D, and I want to know whether it is nonzero over a given interval. I don't even need to know the points (although it would be nice), but I would need to know ...
2
votes
1answer
42 views

Functions that remember some arguments while not remembering other arguments

I would like to some programming that is very generic. Particularly I am interested in the following: Let's say I want to write a function ...
6
votes
1answer
60 views

Using URLExecute to login to website

One of my students is doing summer research for a local company to help analyze some of their data. Trouble is, the web interface they provide for downloading the data only allows one to download one ...
1
vote
1answer
33 views

How to download an archive or directory from Wolfram Cloud?

I don't own Mathematica, but have a (free) Wolfram Cloud account. I'd like to download all of the files in a given Wolfram Cloud directory to my computer. I've used ...
0
votes
1answer
42 views

Forced colorings with IGraph/M

Is it possible to force the colors of certain vertices in a graph so that the function which finds a minimum coloring will then extend the partial coloring with the fewest possible number of extra ...
0
votes
0answers
48 views

Eigenvectors of Hermitian matrices [duplicate]

I asked a similar question in the physics stack exchange, but realized my question is probably more suited here. For any Hermitian matrix $H = H^{\dagger}$ we can write $H = P DP^{\dagger}$ where $P$ ...
0
votes
1answer
27 views

Restore output to notebook

While playing around in settings, I believe I did something to cause all output to be printed to a pop up window. How do I restore the output to the notebook where the evaluation occurs? In options ...
2
votes
2answers
45 views

No difference between TraditionalForm and StandardForm in Graph labels

TraditionalForm seems not to be working properly on Mathematica 11.3 when used in Graph. The following MWE ...
0
votes
1answer
43 views

Power::infy: Infinite expression 1/0. encountered

I am trying to solve the following linear system consisting of four unknowns. ...
5
votes
1answer
252 views

Buliding a larger matrix from a smaller one

I have my matrix $h$ of size $2N\times 2N$ in this form $$h=\begin{pmatrix} a & b \\ c & d \end{pmatrix} $$ where $a,b,c,d$ are smaller matrices which i don't know. Is there any simple way to ...
1
vote
2answers
51 views

Combine points in 3D space by ListPointPlot3D

I have a array and I want to plot it in 3d space by ListPointPlot3D function. ...
-6
votes
0answers
53 views

help me, find my error [on hold]

eq[i_]:={D[u[i][x],x]+(V[i+1][x]-V[i-1][x])/(2 dy)==0,[Rho][i]( u[i]x +V[i]x/(2dy))==(([Mu][i+1]+[Mu][i])(u[i+1][x]-u[i][x])-([Mu][i]+[Mu][i-1])(u[i][x]-u[i-1][x]))/(2(dy)^2 ),u[i][x]D[[Phi][i][x],x]+...
0
votes
0answers
33 views

InterpolatingFunction in NSolve

I'm trying to get NSolve to solve a simple system of equations. It makes use of various interpolating functions (for thermodynamic properties). I can solve the system outside of NSolve by ordering the ...
2
votes
1answer
48 views

How to delete duplicates in the following example?

COnsider a list table = {{x1,y1,z1,t1},{x2,y2,z2,t2},...} How to remove duplicates having the same values of {y,z} (say, {1,2,3,5},{99,2,3,9})? It is not ...
2
votes
0answers
32 views

The function VertexContract does not work in specific case

I am using the function VertexContract and I am experiencing that it does not work in some specific cases. If I give the graph with EdgeWeights, EdgeLabels and VertexLabels, I cannot contract {2,5} ...
1
vote
1answer
31 views

Putting legends within the frame of the plot at the desired position

dat1krafull = {{1.`, 2.61594`*^-8}, {10.`, 7.10017`*^-9}, {50.`, 2.1565*^-9}, {75., 1.6567...
1
vote
1answer
36 views

How can I plot the 3D diagram of x[t], x`[t] and a parameter ηb as the three axes?

I have ploted a 2D diagram with ParametricPlot for the equations. The codes ...

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