1
vote
0answers
68 views

RowReduce doesn't work for this matrix?

I have this matrix A={{0,1,1,w},{1,0,1,x},{-1,0,1,y},{0,1,1,z}} where w, x, y, z are arbitrary constants. This matrix should be row reduced to the form ...
3
votes
0answers
85 views

Exposing .csv via Wolfram Cloud API

I'm sure there's a better way to accomplish this, but my goal is to generate a .csv file from a running notebook, and have it accessible by API. In the main program, I'm exporting the data like so: ...
0
votes
1answer
78 views

RegionPlot Difficulty

This code: Plot3D[ArcTan[Tan[y/x]], {x, -1, 2}, {y, -2, 1}, RegionFunction -> Function[{x, y}, 1 <= x^2 + y^2 <= 4 && y <= x]] Give this ...
1
vote
1answer
162 views

Image shaking when Manipulate with slider

How to prevent the Graphics3D object in following code from shaking when continuously changing the phi parameter? ...
2
votes
1answer
143 views

How to handle Indeterminate TimeConstrain

I have to use Timeconstrained[aux] first for avoid some bigs calculation that dont need and it use a lot of time of calculate, so i can't do this. ...
1
vote
1answer
122 views

Tough Calculation, novice mathematica user

I have an equation, that I've been calling $b_N(x)$ that satisfies the following identity: $$-Nb_N(x)^2=(x-N)b_N(x)+xb_N'(x)$$ where $b_N'(x)$ is the first derivative. I take the derivative then of ...
0
votes
1answer
102 views

Multidimensional NIntegrate problem of the function decaying as 1/x^2

The function I am trying to integrate is more complicated but I can simply write the function as (I had made a typo error, sorry. The '+' sign in front of the r should be '-'): $f(\omega ) = \int ...
1
vote
0answers
246 views

NDSolve error message: Cannot find starting value for the variable y'

I'm attempting to solve a differential equation using NDSolve. This is the code: ...
4
votes
2answers
94 views

Dependent probabilities distributions?

What's the best way to model situations with dependencies? What I mean is well-defined arrangements like: If I choose a 6-sided die with probability $p$ and a 20-sided one otherwise, and then roll ...
13
votes
2answers
2k views

Which Mathematica function has the longest name (by character length?)

I came across DamerauLevenshteinDistance[u,v] in the documentation center so that got me thinking: Which documented Mathematica function has the longest name? ...
2
votes
1answer
88 views

How to suppress clutter parentheses in output?

Dozens of unnecessary parentheses are making my output hard to read. For example, this: expr = D[f[x], {x, 2}]^2; returns this: (* f"[x]^2 *) But when I try ...
7
votes
1answer
196 views

How to intelligently use Binarize[] to find the surface concentration of an image?

A tiny bit of context: I'm using a TEM to take images of deposited metal on a surface. The images are in black and white. The deposited material forms little islands, and I want to use MM to figure ...
2
votes
1answer
189 views

Analytic approximation of NDSOLVE

I have to solve the following differential equation L'[t] == L[t]^(-3/2) - 0.1 I tried DSolve: ...
0
votes
1answer
362 views

Integrating elements from matrix

oI'm kinda new at using Mathematica. What I'm trying to do is create a matrix with elements inside. ...
1
vote
0answers
154 views

How to export LaTeX expressions with subscripts and greek letters?

I am constantly using the mathematica software and using TeXForm command to go back and forth between the calculations and the latex document I'm typesetting. However, mathematica won't allow me to ...
7
votes
2answers
180 views

Where put or edit an init.m to add menu commands?

In this question, answers were given that worked to add items to some menu commands, e.g., additional colors on the Format > Background Color menu, or Help menu items. I have code for such in an ...
1
vote
1answer
229 views

Unintended effect of closing square bracket on Spanish keyboard in Mathematica online

I have only just started using Mathematica Online and I have encountered a problem already with the ubiquitous closing square bracket ] using a Spanish key board. I ...
0
votes
1answer
481 views

StreamPlot in a system x´ = f[x] + g[t] [closed]

StreamPlot can be used in the O.D.E system: x' = 2 x - 3 y + 3 t y' = 5 x + y - t How? ...
3
votes
1answer
223 views

Translate Image respect to its centroid

To apply DistanceTransform for shape recognition, I want to center all images in a fixed point {cx,cy}. I mean each image's centroid should be ...
2
votes
3answers
83 views

How to manipulate one column of a table using the value in another column

Let's imagine I have the following table structure data = {{a, b}, {c, d}, {e, f}}; and I want to transform it into the following table ...
2
votes
1answer
92 views

Statistical Analyzis of Observed Data (Queuing Process)

Basically I have a process that belongs to a certain state at any point of time. However, the time intervals are not fixed (in fact they are exponentially distributed). Essentially, the data points ...
2
votes
0answers
119 views

Interpolation of Singular Functions

I am trying to interpolate discontinuous functions for R in interval $[0,100]$ and r in interval $[0,100]$: ...
1
vote
3answers
198 views

A rule replacement problem: list -> list

Suppose I have a vector function f[x_] := {x[[1]]^2 - x[[2]]^2, Sin[x[[1]]] + Cos[x[[2]]]}; Then I want to make a list of gradients at some values: ...
0
votes
2answers
83 views

How do I tell pattern searcher the order in which to search for patterns given in general form?

I have a really long sequence of Symbols inside a function, say nonCommute[a,b,c,e,e,f,g,b,i,j], and I am implementing a ...
2
votes
1answer
61 views

Searching for symbol except within subexpressions with a particular Head

I would like to write a searcher like FreeQ that looks for a Symbol (or Head) in an ...
1
vote
2answers
515 views

How can I plot a 3-variables function to identify the neutral surface and a region

I wanted to plot a 3-D solid region, in which my function f(x,y,z)= x (1/(1 + 0.06))^3 + y (1/(1 + 0.06))^2 + (2 z^2)/15 (Sin[10 Degree])^2 -z/3 Cos[10 Degree] ...
4
votes
2answers
99 views

How do I localize an assignment to expression (instead of symbol) within scoping construct?

Is it possible to localize an assignment to an expression (defined via UpSet) instead of a Symbol within a scoping construct? ...
1
vote
2answers
125 views

replace two elements in a list with the sum of those two elements?

I have a list: G[3] = {2, 4, 2, 4, 2, 4, 2, 4, 2, 4} (there's a 3 in there for the 3rd Prime) Recursively defined by: ...
1
vote
1answer
77 views

Increment in Manipulate does not seem correct

I am reading the documentation for the Manipulate command and I've done this code: ...
5
votes
1answer
121 views

Bug in grouping after editing code?

While looking at A question about conditional replacement I think I discovered a bug in the Front End that affects both 7.0.1 and 10.0.1 under Windows. If I copy and paste this line into a new Cell ...
0
votes
0answers
22 views

A question about conditional replacement [duplicate]

{g[x, y, z], h[x, y], f[]} /. (f_[t___] /; f != List) :> Plus[t] Why is the output of this expression ...
3
votes
2answers
150 views

RandomFunction and Histograms

RandomFunction[QueueingProcess[3, 5], {0, 15}] Histogram[data, Automatic, "PDF"] gives a very nice way to see the histogram based on the specified process. ...
4
votes
1answer
135 views

Using `N` gives strange result

Consider these two functions which are almost the same: ...
1
vote
0answers
128 views

How to get smooth playback of image sequence

I would like smooth animation of a sequence of images, without the controls displayed by ListAnimate. I have a very simple playback function ...
1
vote
1answer
53 views

Off[FinancialData::notent] fails on first run but works thereafter

Off[FinancialData::notent] fails on first run but works thereafter. So what good is it in this case? Is there a trick to force first time success? I've tried ...
5
votes
1answer
84 views

“ComputedDate”'s interpretation of “next”

Today Interpreter["ComputedDate"] /@ {"next Monday", "next Tuesday", "next Wednesday"} What explains this behavior? Can ...
8
votes
1answer
730 views

MKL on Intel vs AMD

I am running some linear algebra functions in Mathematica on different CPUs. I've noticed a massive performance difference between Intel and AMD processors. For a certain script I wrote that uses ...
5
votes
1answer
259 views

Inverse error function

I solved some equation in Mathematica and I obtained something like $$y(t)=\exp \left\lbrace \left[ \text{erf}^{-1} (\text{i}t) \right]^2\right\rbrace, (1)$$ where $\text{i}$ is imaginary unit and ...
21
votes
2answers
322 views

Backslide of Limit

A friend of mine showed me this example: Limit[Sum[Sin[Pi*k/n]/(n + 1/k), {k, 1, n}], n -> Infinity] This sample calculates well in v8.0.4: but not in ...
1
vote
0answers
31 views

How to make Expand work right in a function definition?

This works just fine: Derivative[n_, 1][g][x_, v_] := D[g[x, v], {x, n + 2}]/2 + D[D[g[x, v], x]^2/2, {x, n}]; h = Expand[D[g[x, v], {v, 3}]] I would like to ...
6
votes
1answer
195 views

Parentheses for negative integers

Trying to standard create prime factors presentation, but can't seem to remove the parentheses: ...
1
vote
1answer
149 views

Why Abs[Infinity] is an element of the real numbers

Element[Abs[Infinity], Complexes] returns False, that's right. But ...
3
votes
2answers
149 views

Compare two shifted signals

I have one set of original data (signal A) and a second set of derived data (signal B) which was computed from A by position rotation (circular shift). Here are the data for the signals (A and B): ...
6
votes
1answer
138 views

How can I number the section titles automatically in Mathematica?

When I write a document in Mathematica, I do not like to number the section title myself, because I usually add or delete a section from time to time. Is there a way that Mathematica can number the ...
0
votes
0answers
103 views

Unequal behaviour of FindRoot to two similar functions

Unfortunately, I have some difficulties to plot a function. Here is my code: ...
6
votes
1answer
483 views

Get 2d corner coordinates / layout using edge detection

I'm new to Mathematica but I found an interesting usage of it: I'm programming a 2D game, with a top-view, where I'd like to have the edge coordinates of the walls. EdgeDetection delivers me quite a ...
1
vote
1answer
96 views

symbolic integration of product of hankel function and trignometric function

I want to perform the following integration. my function is : r*cos(r)hankel(0,kr) i want to integrate from 0->pi , and want to get the expression in terms of k. I used this command ...
0
votes
0answers
44 views

Should this be equal to Gamma function or not?

I define the following function: Nat2[s_] := InverseFourierTransform[FourierTransform[1/t, t, w] (-I w)^(s - 1), w, x]/Cos[Pi (s - 1)] /. x -> 1 I expected ...
0
votes
3answers
214 views

Simple pattern/texture on chart elements [duplicate]

If I print the following BarChart in black and white, then it is very difficult to tell which bar is "a" and which is "b". ...
0
votes
0answers
141 views

Nested Recursion Equation

I have been trying to solve a "nested recursion equation" using Mathematica. However, when I do something like this: ...

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