0
votes
0answers
14 views

On the order of rules specification

I wanted to understand how Mathematica parses function definitions in rules-based programming, so I started with the simple code: ...
0
votes
3answers
30 views

Alternatives to Append/AppendTo for generating a list in an interactive DynamicModule?

I have a stack of timelapse microscopy images that I am trying to segment frame-by-frame using some of Mathematica's image processing functions. I have created a little interactive DynamicModule with ...
0
votes
0answers
17 views

Hypergeometric Function of Matrix Argument

I am looking for the evaluation of a Hypergeometric function with a matrix argument as for example in Ploev and Edelman: http://math.mit.edu/~plamen/files/hyper.pdf or as showcased in the Wikipedia ...
0
votes
1answer
42 views

Numerical error in Mathieu functions

Consider the MathieuCharacteristicA function, which is a piecewise function according to the documentation. The discontinuity happens at integer number. ...
2
votes
2answers
44 views

Local variables whose definitions depend on each other [duplicate]

Consider the following (pseudo-)function definition: f[l_] := Let[{ a = Length[l], b = First[l], c = b/a, }, c*10] So for ...
1
vote
0answers
41 views

Interpolating function into an actual function

I numerically solved an integral equation and the result is an InterpolatingFunction. I plotted it to see how the function behaves but I also need an actual ...
2
votes
1answer
19 views

ExportString and HTML: where are saved images?

I want to use ExportString to generate HTML expression. Here is an easy example: ExportString[x^3, "HTML", "FullDocument" -> False] gives ...
5
votes
1answer
40 views

ListPolarPlot: 0 Degree at vertical axis

Is it possible to have ListPolarPlot start plotting at the vertical axis? By Default ListPolarPlot gives this result: ...
3
votes
2answers
65 views

Numerical value of physical constants Mathematica 10

Is there a way to use the physical constants in calculations and have Mathematica 10 figure out the final unit and numerical magnitude? When I try ...
1
vote
1answer
37 views
0
votes
0answers
16 views

How to deal with matrices involved in system of SDEs?

This question is in continuation of the the previous posts enter link description here and enter link description here. What I want to do is numerically solving the epidemic model which can be defined ...
3
votes
2answers
37 views

Filling dependence on order of points in ListPlot

ListPlot[{{{1, 0}, {0, 0.5}}, {{1, 1}, {0, 1}}}, Filling -> {1 -> {2}}, FillingStyle -> LightGray, Joined -> True, Frame -> True] Results in no ...
2
votes
0answers
34 views

Some global variables are defined even at the start of a fresh session

In a fresh Mathematica session evaluating Names["Global`*"] doesn't give an empty list. The result is either {rhs, z} ...
4
votes
2answers
44 views

Problem with general assumptions

I hope I am not to redundant with my questions. As part of solving a physical problem, I want to assume once and for all that all my variables and parameters are real, positive and finite. Is it ...
17
votes
2answers
194 views

Object separation from a 2.5D surface

I'm trying to identify the shape and the boundaries of objects. The data was generated with a laser scanner and represent the surface of an area in which many boulders lay on the ground and making up ...
0
votes
1answer
70 views

Specifying initial conditions for a PDE

I have simple diffusion equation with point source at c(0, t) = 1 and initial condition c(elsewhere, 0) = 0. How should I apply ...
6
votes
1answer
211 views

Tuples without self-loop

I have a simple question coincerning the Mathematica function Tuple. Currently, I apply the following code ...
2
votes
0answers
28 views

Efficient processing of Special Ordered Sets with LinearProgramming

I'm playing with integer linear programming, especially problems involving lots of constraints which would appear to be special ordered sets. Below is a toy example, three last rows of the matrix ...
0
votes
0answers
50 views

What is the meaning of a result of {{}}? [on hold]

What does an output of {{}} mean in Mathematica after solving a system such as: $e^{x}=e^{x}$ for $x$?
2
votes
0answers
61 views

How to solve three equations with four unknowns iteratively?

I have three equations of the form $\quad \eta = f(N1L, N2L)$ $\quad N1L = g(\eta, R)$ $\quad N2L = h(\eta, R)$ I want to eliminate $\eta$, so that I can get $N1L$ and $N2L$ for a range of $R$. I ...
2
votes
0answers
46 views

Program file deleted while running

I have a program running for some time at one computer. Today, unintentionally, I edited the program file from another computer (I use Dropbox), and the program kept running. Trying to correct my ...
10
votes
2answers
275 views

Find maximum value of interpolation function - obviously wrong result

Minimizing and maximizing interpolation function has already been asked and answered, see here for example. Yet, I observe a strange behaviour. Well, I can understand that the wrong guess of ...
6
votes
2answers
91 views

Export MatrixPlot graphics to PDF

I am trying to export a plot generated by MatrixPlot to PDF but am having problems with the way the exported PDF is rendered. ...
2
votes
0answers
78 views

Power::infy: error using FindFit

I have a 2D data to fit (the Airy type pattern from diffraction of Gaussian beam on the circular aperture). Please see the attached picture. I was going to use a function like ...
3
votes
3answers
85 views

Solving determinant of a Kronecker product of matrices gives a numerical error - why?

I am doing the following steps (code at the end of the post): I start with a 2x2 matrix (smatrix), which is a function of a single variable (u2). I want to set the determinant of this matrix ...
3
votes
3answers
95 views

Transformation of Derivatives under change of coordinates [duplicate]

I have an expression depending on the two variables z and t, and the derivative of a known function $f(t,z)$. Something like: $$myexp \ =\ t\ z\ \partial_z\ f(t,z)$$ Now I want to make a change of ...
1
vote
2answers
88 views

How to do a region plot with many functions [duplicate]

Hello i am trying to compare many function, i want to see witch one as the lowest value depending on 2 variables. My solution so far is something like this: I have 7 function: P1 P2 P3 P4 P5 P6 P7, ...
0
votes
0answers
11 views

Applying chain rule to evaluate a derivative when the component function is not differentiable at one point [migrated]

I got the following question. Can anyone help me? Thanks! Y is a smooth function of X. and X is a function of r, which kinks at r=r0, but is smooth everywhere else. I was try to compute dY/dX at ...
0
votes
0answers
42 views

Extract the minimum positive root from a quintic [on hold]

I need to compute the values of ϵϵ and x2 from the following sytem: ...
0
votes
0answers
72 views

plot $f(x)$ against $\frac{1}{x}$ [on hold]

Hi guys this is really a simple question: if i have $f(x)$ how do i plot this function in mathematica against, for example, $\frac{1}{x}$? thanks in advance
9
votes
8answers
367 views

UnFlatten an array into a ragged matrix

Trying to unflatten an array that was part of ragged array of sub matrices. As input we have flattened array: ...
6
votes
2answers
47 views

Recursive function with array of variables

I am trying to create a recursive function which works with an increasing array of variables. Since the formula is quite complex, i will try to simplify my example to the core of my problem. The ...
1
vote
0answers
19 views

Conditions for proper integrals with DSolve on Mathematica

DSolve[{RCS'[s] == SNPH[s] - Sqrt[R2[s] - RCS[s]^2]/b,SNPH'[s] == RCS[s]/a^2, R2'[s] == 2 RCS[s] SNPH[s], RCS[0] == 0., SNPH[0] == snal, R2[0] == ri2}, {RCS, SNPH, R2}, s ]; Here {a,b,snal,r12} are ...
3
votes
5answers
184 views

Ordering the Boundary points of a Polygon

I feel like this should be simple, but I keep running into walls. Say someone gives you the coordinates of the vertices of a pentagon and the center point of the hexagon. Is there any way to get an ...
0
votes
1answer
52 views

Interpolation of 4D data

To create a table and an interpolation function of 3D data T=f(X,Y) I have the answer here: interpolation of 3D data How to create a table/interpolation function of 4D data T=f(X,Y,R)? If I do ...
2
votes
0answers
39 views

Problems running Mathematica 10 with Workbench 2 Windows 7 64 bit

My Workbench runs perfectly using Mathematica 9, however simple things which run just using the Mathematica 10 front end won't run when using Mathematica 10 and Workbench 2. These simple two lines of ...
1
vote
2answers
46 views

Listlineplot starting from 0 [on hold]

I got a matrix which looks the following and should be seen as a list of pairs with (x,y) coordinates: test = {{0, 1, 2, 3}, {11000, 23940., 36880., 49820.}}; ...
0
votes
1answer
51 views

NDSolveValue producing message: Input is not an ordinary differential equation

I have an urgent question for my program because I get always an error output for it. I have a partial differential equation that I want to solve with NDSolveValue. ...
7
votes
5answers
175 views

How to do DateDifference on table items containing dates

I have a Table with data in form {{date}, value}: ...
3
votes
2answers
139 views

Create a shortest-path - edge matrix

I am currently struggling with a problem in Matehmatica. I have a weighted BarabasiAlbertGraph and a corresponding demand matrix of the same size. I then calculted the shortest path from each vertex ...
6
votes
1answer
139 views

Wrong values at the boundary of differential equation solution

I have a second order ordinary differential equation and want to solve it numerically. Although I have specified values at the boundary, Mathematica solution does not match with boundary conditions. ...
0
votes
0answers
59 views

Why does Mathematica have trouble with this simple set of simultaneous equations? [on hold]

The code in question is: Solve[{x == r*Cos[\[Theta]], y == r*Sin[\[Theta]]}, {r, \[Theta]}]. I'm a newbie so this might be fairly basic, but shouldn't this work? ...
-1
votes
0answers
26 views

if f(x) is O(g(n)), then does it follows that h(f(x)) is in O(h(g(x))? [on hold]

if f(x) is O(g(n)), then does it follows that h(f(x)) is in O(h(g(x))? Can we prove or disprove it? In my class, we proved that nlogn is in O(log(n!)) But n^n is not in O(n!) It just feels weird.
4
votes
1answer
159 views
6
votes
1answer
150 views

How to make Epilog render behind the main plot [duplicate]

Consider this example: ...
0
votes
0answers
85 views

Dual core CPU — Mathematica uses only 29% of one core [on hold]

I hope that this question hasn't been answered, yet. At least I couldn't find any answers to that for quite some time now. I am using Mathematica 9 on windows 8. I have two cores. My calculations ...
1
vote
1answer
72 views

Missing arrow tips and colors

My main problem is: I plotted a curve here, but the tip of some arrows are missing. Why does this happen, and how can I fix this? Not the main problem: Also, I once tried to make the arrows with ...
5
votes
2answers
271 views

Is it possible to produce “tilt-shift” effect in Mathematica?

I attempted to produce a kind of miniature faking look from a street scene photo. I tried to shift the perspective lines close to parallel to each other to obtain such effect. However, the result ...
1
vote
1answer
62 views

How to lookup by a string key after GroupBy? Inconsistent data type handling

This is relates to a bug was introduced in 10.0.0 and shall be fixed in 10.0.1 It also relates to an issue that has yet to be corrected. After applying GroupBy ...

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