2
votes
1answer
488 views

Data filtering using Butterworth filter

I want to filter data using Butterworth filter. I am currently using Matlab and I want to know how to do it in Mathematica. I have the following data: ...
1
vote
0answers
41 views

Plotting a StateResponse inside a loop for some reason gives an error [closed]

/edit Nevermind i figured it out, i now have: ...
1
vote
1answer
116 views

Revert y-axis in RegionPlot

I have the following code: ...
0
votes
2answers
95 views

How to generate a list with a loop, and put it into a variable?

I am pretty new to Mathematica and to coding in general. I want to do a very specific thing, but I unable to do it. Please explain in detail how I can make this work. Here's the details on what I am ...
1
vote
0answers
33 views

Correct use of Mathlink's MLGetRealList

I am attempting to use Mathlink from C. I have managed to return single values from mathlink to my c program, but I am having trouble with lists. Consider the Mathematica operation: ...
3
votes
2answers
180 views

Controlling spacing of histograms in Histogram3D

I have five histograms, hist1 = Histogram[data1, 20], to which I append {1, 2, 3, 4, 5} via ...
2
votes
0answers
520 views

FindRoot in range

I am trying to find all roots in a range, using y /. FindRoot[Sin[y] == 0, {y, #}] & /@ Range[7] which gives ...
0
votes
1answer
154 views

How to solve this integral equation?

I am trying to solve for x the integral equation : ...
0
votes
0answers
57 views

TableDirection in TableForm

I got confused about what does "the outermost dimension" and "the first dimension" mean in the document I snipped. Does it mean row or column?
0
votes
0answers
108 views

an NIntegrate inside a manipulate in mathematica was working and suddenly won't work now. it says indeterminent and it doesn't make any sense why

my title says pretty much everything heres what I'm entering. NumericQ returns a false value but it was true before. Im loosing my patience because this is so ...
4
votes
1answer
114 views

How to do assignments through MathLink?

In Mathematica I can make the assignment 'foo = bar' with Set[foo,bar]. However, if I try to evaluate 'Set[foo,bar]' through MathLink then it appears that MathLink gets stuck while trying to read ...
2
votes
2answers
159 views

Issue with Set function

Tables often come with column headers. Indexing the columns with the header is a natural thing to do. Although a proper dictionary is the usual solution in such a case, I find it often practical and ...
0
votes
2answers
95 views

Manipulate executes twice [closed]

I need help, guys! Here the script: ...
10
votes
2answers
393 views

Select cases from a list

I have a list in the form : {1,1,1,0,-1,-1,1,1,1,0,0,0,0,-1,-1} No I'm trying to select only those sequences which start with 1 have a zero (or many zeros) ...
2
votes
2answers
205 views

How to select the first “lowest” (first valley) number in a list?

I would to select the first valley of the list of coordinates below. It should be {3, 1}. ...
1
vote
2answers
156 views

X-Y scatterplot

Hi I have a simple question. How do I plot the following with Day 1 as my X axis and Day 2 as my Y axis? I need the 22 variances plotted according to the Day they were taken from (these were ...
0
votes
1answer
94 views

Matrix Operation

I have a $3\times3$ matrix A, and a function sTrans that outputs two $3\times3$ matrices in a list when given a $3\times3$ ...
3
votes
1answer
197 views

Little triangles appearing in a Mathematica region plot with “opacity” saved in a PDF file [duplicate]

I am trying to produce a region plot of many functions, but Mathematica keeps showing me the little triangles when I save it as pdf. I have seen other solutions which fix the problem with PlotStyle-> ...
1
vote
0answers
53 views

Conjugate of InterpolatingFunction?

From NDSolve, I got this: {{a1 -> InterpolatingFunction[{{0., 40.}}, "<>"]}} What would be a sensible approach to ...
0
votes
0answers
104 views

Manipulate for Electric Field

I'm kind of new to Mathematica but I'm getting the hang of it slowly. Anyways, I'm trying to do a project on the electric field of two particles so my professor helped me with this code (sorry in ...
0
votes
0answers
79 views

Find the values of parameters so that the matrix is symmetric positive definite

Good evening , I have a matrix 20x20 in symbolic form. The matrix depends on 5 parameters (a,b,c,d,e). I would like to get the interval of each parameters that ensures that the matrix S is symmetric ...
6
votes
1answer
121 views

When to use GenerateConditions -> True

Many functions, usuallly those involving integration, take a GenerateConditions option which often defaults to False, or at ...
2
votes
1answer
191 views

Generating the set of all strings within a fixed edit distance of a initial string?

Provided a starting string initialString, and a particular alphabet of allowed characters {"A","B","C","D","E",...}, how can I ...
0
votes
1answer
113 views

Loading Statistics`Library`

I need to use a number of functions from theStatistics`Library` namespace. Since that is a bit of a mouthful I would like to import it, but I get errors: ...
4
votes
2answers
220 views

How can I avoid getting the error message Goto::nolabel in my code?

If anyone could suggest a reason why Label[begin] ... Goto[begin] would return Hold[Goto[Begin]], and (better) how can I avoid ...
1
vote
1answer
224 views

Overlay Rectangle on a ListPlot

I have a ListPlot of 100 data points in the range of 0 and 1. Now I'm trying to find a way to overlay (four) rectangles onto the listplot in 0.25 steps horizontally. Essentially I just have BinLists ...
2
votes
1answer
285 views

Importing data from excel and assigning a variable to each of its columns

How should I assign variables to the data imported from excel containing 3 columns which are time, mean and standard deviation. I want to perform operations on the three variables to get new ...
0
votes
0answers
99 views

Ticks don't display on Y-Axis of Histogram when using PlotRange

I have a histogram, if I create it without specifying the PlotRange it works fine and the ticks on the Y-Axis are displayed ...
10
votes
0answers
180 views

Strategies to find curves on messy data using FindCurvePath

I have a set of data points that correspond to roots of a transcendental equation with respect to a parameter (the abscissa) which, by the properties of the system, define continuous curves (might be ...
5
votes
1answer
281 views

Variable number of nested variable-range sums

I would like to express the following nested sum in Mathematica: $$ S(m,j,N) = \sum_{k_1=m+j-1}^{N-1} f(N,k_1) \sum_{k_2=m+j-2}^{k_1-1} f(k_1,k_2) \cdots \sum_{k_m=j}^{k_{m-1}-1} f(k_{m-1},k_m) $$ ...
6
votes
1answer
454 views

Efficient JSON parser for Mathematica

Im looking for a efficient way of parsing JSON data in Mathematica. I am having a lot of problems with ImportString because it uses Java, is too slow, and uses too ...
1
vote
2answers
139 views

How to sort the adjecency matrix of bipartite graph so to have two off-diagonal blocks

In a bipartite graphs there are two class of nodes, say A and B. Each node of class A may interact only with nodes of the class B, and viceversa. The corresponding adjecency matrix is thus composed by ...
1
vote
0answers
73 views

Solving for a charge distribution from a dipole moment [closed]

I've been looking around but I haven't been able to find any way of solving this conceptually simple problem. In short I am trying to find the charge density in a dielectric in an external electric ...
5
votes
3answers
425 views

Where can I find a dark stylesheet for mathematica?

The default white is very tiring for the eye after some hours.
0
votes
2answers
144 views

Expand expression into quotient of negative power series

I have a function T(z) and want to expand it to the following form: At the end I want to have a list of equations, which can calculate a0, a1, a2, b0, b1 and b2 with different values of h1, h2, ...
0
votes
2answers
72 views

How can I troubleshoot a PDF that fails to import?

I'm trying to import a PDF file whose text I'd like to parse, but I'm getting an error with no explanation: ...
4
votes
3answers
350 views

Finding parameters making real part of eigenvalues vanish

I have the following $\;3\times3$ matrix: $\left( \begin{array}{ccc} 0.04 -0.4 b & 0 & 0.04 -0.4 b \\ 0 & -0.08-1.2 b & -0.06-0.9 b \\ 1.04 -0.4 b & 2.08 -0.8 b & 0 ...
3
votes
1answer
231 views

Surface area of intersecting spheres

Given a sphere of radius 1 centered at the origin and $n$ spheres with radii $r_i$ centered at predefined coordinates, $c_i$, in space, I am after the surface area of the unit sphere that is not ...
2
votes
1answer
176 views

Integrate does not accept my integrand expression

I want to calculate the symbolic integral, but I could not obtain the final results from Mathematica. ...
1
vote
0answers
86 views

Inhomogeneous phase-portrait with StreamPlot [duplicate]

I have a problem with a must-be simple streamplot. The potential function governing the motion is U, and I have the following code in Mathematica: ...
4
votes
1answer
282 views

Understanding of method for NDSolve

I used automatic method for NDSolve. Then I asked myself - which method Mathemathica prefered? I got an answer for this question on this forum, that I need to use: ...
1
vote
1answer
68 views

How do I visualize the result of EdgeColoring[g]?

Combinatorica has a heuristic edge-coloring function EdgeColoring. When I execute it on a graph, the result is a list of integers. My guess is that an integer $i$ ...
3
votes
2answers
97 views

Finding all instances of length $N$ common subwords in two strings

Given a pair of strings, I'd like to return a list of all common subwords of a fixed length of "n" characters (i.e. contiguous subwords of length "n" that occur in both strings), allowing for ...
0
votes
1answer
80 views

How to test if any set of pairs contains elements of other list? no matter order of elements

I want to detect if a set of pairs, for example a={{2,5},{6,3},{1,4},{8,7}} contains a given pair, for example tabu={{4,1},{2,6}} but don´t be relevant the order inside pair (pair {i,j} is equal to ...
2
votes
1answer
373 views

Different Poincaré maps for same Equation

I've seen the Wolfram Poincaré example. I'd like to modify this sample in order to have a list of Poincaré maps. In the example the event is captured only when ...
0
votes
0answers
27 views

How to switch elements i,j in a list? [duplicate]

Are there any direct function to switch elements i,j in any list? or is necessary to create one with Do / If ? (I don´t ask for making me this function if it doesn´t exists) My target is can ...
6
votes
3answers
538 views

Visualization of matrix transformations

I define the "matrix transformation" here as follows: $\left[ \begin{matrix} x_1' \\ x_2' \\ \end{matrix} \right]=\left[ \begin{matrix} a & b \\ c & d \\ \end{matrix} ...
7
votes
2answers
398 views

Nothing appears in simple plot

I'm trying to get the following simple code to work. (The code is just supposed to graph the norm of the second derivative of a vector function). ...
0
votes
1answer
62 views

Questions regarding DictionaryLookup of Mathematica

a. Make a function longest[lang_] that gives the length of the longest word in the dictionary of lang. You should get ...
4
votes
1answer
214 views

Find lengths of contours in a ContourPlot

I am trying to find the lengths of different contours in the following plot: It is a complicated piecewise function evaluated on the unit disk. I am hoping there is an easy, generalized way to ...

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