# All Questions

79 views

### Some global variables are defined even at the start of a fresh session [duplicate]

In a fresh Mathematica session evaluating Names["Global`*"] doesn't give an empty list. The result is either {rhs, z} ...
120 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 ...
585 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 ...
151 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 ...
319 views

### Tuples without self-loop

I have a simple question coincerning the Mathematica function Tuple. Currently, I apply the following code ...
91 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 ...
216 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 ...
57 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 ...
2k 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 ...
423 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. ...
171 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 ...
461 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 ...
151 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, ...
710 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: ...
143 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 ...
63 views

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768 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 ...
324 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 ...
517 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 ...
48 views

Let ...
229 views

### How to do DateDifference on table items containing dates

I have a Table with data in form {{date}, value}: ...
399 views

### How to create a 'shortest-path link matrix'?

I am currently struggling with a problem in Mathematica. I have a randomly generated weighted Barabasi-Albert graph and a corresponding demand matrix of the same size. I'm generating the graph with ...
166 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. ...
418 views

### Can I check if an expression is positive using assumptions?

I have the following notebook: ...
194 views

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

Consider this example: ...
156 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 ...
390 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 ...
203 views

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

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

### Rational display with Quantity

Why is that Power[Quantity["ElectricConstant"],-1] is represent different of Power[Pi,-1] What I am doing wrong ?
105 views

### Unusual Slow Down with LocatorPane/DynamicModule

I have coded up a little interactive DynamicModule to help me with image processing/segmentation of stacks of timelapse microscopy images. I am experiencing a crippling slow down in the ...
384 views

### Fredholm integral equation of the second kind with kernel containing Bessel and Struve functions

I need to solve this Fredholm integral equation of the second kind: f[s]+integrate[f[t] K[s,t],{t,0,1}]=s where ...
145 views

### Compiler stack overflow [closed]

I tried to compile a huge function. I used these options: ...
201 views

### Replace Missing[Unmatched] with zero

After a left JoinAcross, I have a number of Missing["Unmatched"] values in my list of associations. I'd like to set them all ...
132 views

### Grid rows height & SpanFromAbove issue

I would like to understand why the following code produces such a different result (Mathematica 9, Win7). Is this a bug? Is there a way to avoid this line height problem? ...
580 views

### What is my problem with MeshFunction?

I want plot the max value in a sine plot. We can use the following code ...
286 views

### Citation of the algorithms used in FindGraphCommunities

For my research work I need to put a comparison of different community detection algorithms. Instead of implementing all those algorithms once again, I would like to use the methods already provided ...
93 views

### An efficient way to merge a pair of 4d arrays of non regular length lists

Question I have two 4 dimensional non regular length lists of complex values. I have working code however it seems quite slow and I am not sure how I could improve this. Mathematically I am trying ...
858 views

### Blurred frontend text in Mathematica 10, Windows, High-DPI Display

So I have recently upgraded to a Windows ultrabook with a high resolution display. All my software seems to cope just fine with the high resolution, except for Mathematica 10. Mathematica seems to ...
309 views

### Selectively updating individual graphics in a dynamic, multiple-plot Show

Suppose Show contains multiple graphics objects that differ markedly in the amount of computation needed for their display. Hence, when dynamically updating only ...
52 views

### Is it possible to pass a “shared” integer in librarylink?

MTensor supports shared pass, where the argument can be modified in the library function and that modification can be seen in Mathematica side. Is it possible to do the same thing to a integer or ...
151 views

### Locators, lists of variable length, all in Manipulate

I'm trying to implement a complicated Manipulate[] interface. I'm not really interested in working code, but for those interested, I would like the program to allow you to drag around a variable ...
80 views

### Listable compiled functions used in NMinimize [duplicate]

This is an example from MMA: cListable = Compile[{x}, (x-1)^2, RuntimeAttributes -> {Listable}] In case of single entry: ...
366 views

### Exporting a compiled function for later use

I wish to export compiled functions for later use. This means that I do not want the compiled function to be recompiled every time I reload it. It also means that if my compiled function was for ...
262 views

### difficulty abstracting the OptionValue pattern

I am building lots of functions that use Options and OptionValue and wanted to reduce the redundancy in the expressions that ...
527 views

### Find patterns in a list

again, I have a list like this: ...
135 views

I'm trying to do some calculations here, but for some reason Mathematica starts using numerical approximations that are no good for my work. Specifically: ...
123 views

### Proper EdgeForm setting so boundary appears entirely within shape

I have two neighboring (complicated) polygons that I want to be displayed with thick boundaries, however the two shapes border one another, and as EdgeForm places the line centered upon the polygon's ...
184 views

### FindFit with parameters which are simultaneously in initial conditions

I have RLC circuit. I would like to find R and L by using FindFit, but L is in initial condition and I have problem with it. Could you help me ? ...