# All Questions

198 views

### Best way to represent a complex time schedule?

What would be the best way to represent a complex schedule in Mathematica ? For example a representation of the plain words schedule: "From Monday to Friday, from 8 am to 12pm and from 1pm to 4pm", ...
269 views

### How to generate a random flow graph?

A flow graph is a rooted directed graph that the root reaches all other vertices. I need to generate a random flow graph in Mathematica. My idea is to use ...
55 views

### Subsituting expressions for expressions

I'm trying to define functions using other functions, like so: f[a_, b_] := a/b; a[c_] := c; b[d_] := d; Now what I want to be able to do is two things: ...
398 views

### How can I use nonlinear model fit with multiple variables? [closed]

I have a data set with four entries. the first three entries correspond to variables in the fit x,y, & z. The fourth entry corresponds to the function value. I am trying to fit this data to a rate ...
78 views

206 views

### How to properly use conditionals inside NDSolve

Currently I am working with Mathematica to learn the program, and I'm confused what exactly is wrong with this code. ...
767 views

### Removing a histogram's vertical edges

Let's say I have a histogram: Histogram[RandomVariate[NormalDistribution[10, 2], 500]] How can I remove vertical lines inside the histogram and keep only the ...
143 views

### Equation solving problem [closed]

I have this code: ...
54 views

### How do I plot an expression in mathematica? [duplicate]

I have the following mathematica expression: ...
93 views

### Constants from differential equations

I have a problem, I've solved 2 diff equations and I have: ...
139 views

### Using LeviCivitaTensor

I have 2 questions about using LeviCivitaTensor, based on the following session: The signs for the cross product seems to come out "opposite" of what I expected. Why is that? Did I miss anything? ...
279 views

### Help with Fourier analysis and filtering of an image

I am starting with the following image: For the curious, it is an STM scanned image of graphite. I am hoping to find some kind of periodic structure in the image related to the honeycomb structure ...
230 views

### Find and return the key with lowest value in association list

I am still new in Mathematica, and I need some help here. Suppose that I have an association ...
273 views

### How to generate normally distributed random number [closed]

I want to sample or return random number from a distribution which is normally distributed with mean of zero and standard deviation of 1. I am using RandomReal[NormalDistribution[0, 1]] I s this ...
86 views

### Arrangements (?) from permutations of rows in a triangle, is there a simpler way to program this?

I am generally confused about integer valued polynomials, and how to count them. Trying to learn the subject I started by listing permutations of the rows in a lower triangular table: \displaystyle ...
79 views

### Replace symbols in output without evaluation

I found the Wolfram example for ExpandNCM but I want a more human-readable output form. I want to evaluate ExpandNCM, for example with ...
181 views

### Why does Mathematica “sleep” when I don't work at computer? [closed]

I started using Mathematica few days ago. I'm running this code: ...
45 views

### StringLength function [duplicate]

allWeatherStations = WeatherData[]; fullformStations = FullForm /@ allWeatherStations; Tally[StringLength /@ fullformStations[[All, 1, 2]]]. This code not working. ...
722 views

### DSolve with assumptions

I'm new to mathematica and was wondering if someone could help me. I have a differential equation which is: $\frac{dy}{dx} = 1/2 y(1 - y)(a - y + a y)$ It has initial condition $y(0) = y0$ and ...
86 views

### How can I combine two plots? [closed]

I am interested in plooting x only from 0 to 1, and afterwards x^2, only from 1 to ... whatever ...
117 views

### Dealing Repeated pattern in StringReplace

A problem about StringReplace When I'm running into this problem possible [bug] ...
606 views

### Better way to visualize cylinder puzzle solution

The above puzzle has been a recent source of amusement in my clique. I decided to provide a visualization to motivate solution (here): My code: ...
100 views

### Plotting vectors using derivatives

This question stems from a previous question I asked here: Multiple Integral of equation including dx prime? An equation describing a gravitational field of a cuboid is given as: \$V(X,Y,Z) = -G\rho ...
360 views

### How could I transform the YYYYDDD date string/Integer to YYYYMMDD date string?

suppose I have lots of YYYYDDD date Integers which look like(for example): ...
170 views

### How to trim the zeros from the right of a list? [duplicate]

I need to remove the zeros from the right of an integer list up to the first non-zero element. Such as {0,1,0,0,2,0,0}->{0,1,0,0,2}. Padding zeros can be simply ...
118 views

### Why the flat f[x] is treated as ghostHead_[f[x]]?

While reading this answer I feel confused. If we do not care any specific detail of the original question, then ybeltukov's answer essentially makes use of the following fact ...
195 views

### Solve the “Cheryl's birthday” puzzle using mathematica

The "Cheryl's birthday" puzzle has been circulating around, the backstory is available via wikipedia. The puzzle itself is reproduced here: Albert and Bernard just became friends with Cheryl, and ...
27 views

### Unable to save a notebook as pdf

I have removed all the dynamic and manipulate cells. I can save short selections as pdf, but when I try to select the whole notebook, or use save as - pdf, the result is just one page, sometimes the ...
143 views

### How to import data from a .mat or a .txt file and manipulate dimensions

I'm new to Mathematica (I know very, very little - so I apologize if anything I say is absolutely wrong) - but I'm trying to upload a file from matlab and arrange it in matrix form. I have a .mat ...
301 views

### How to fit parameters in a system of coupled differential equations

Problem description: I'm studying a chemical reaction that can be modeled by a system of coupled differential equations, and I want to use measured data to determine the parameters that appear in the ...
99 views

### How to use an expression for the argument to a function [duplicate]

I would like to define a function over a list of variables like f[a_,b_,c_]:=a+b+c However, when this list is big it makes uncomfortable to read. Can I somehow ...
46 views

### Question on ClusteringComponents [duplicate]

I am fairly new to Mathematica. I've been playing around with ClusteringComponents. Assume we are clustering points in the plane using k-means clustering and ...
151 views

### Absolute VectorPlot scaling

I'm trying to visualize the vector components of a rotation matrix with absolute vector lengths. VectorScale help states that When using an explicit sfun, ...
48 views

### How to invert the default order of polynomial? [duplicate]

By default, Mathematica outputs polynomials starting with smallest degree. How can I invert this?
42 views

### Possible bug of Exporting as HTMLFragment at Linux

This is the result of Mathematica 10.0.2 of Linux Version. There are two style inside one tag, and this fragment cannot be Imported as XML by Mathematica. This is the result of Mathematica 10.1 of ...
45 views

### Truncating a List of Subsets of Ordered Pairs

I have a set of pairs: ...
78 views

### Returning value if a point is in a region?

I'm writing a function so that if the user clicks on a certain region, a value is returned. The function takes in a condition list like the one below and a point. ...
164 views

### Manipulating List?

I have a huge list with 1000 elements. Manually entering and calculating SUM of probabilities it would take a few hours. Example: list = {1, 2, 3, 3, 4, 3} ...
36 views

### ConnectedComponents problem of syntactic structure

In Mathematica 10, ConnectedComponent computes the list of vertices belonging to strongly connected components. In the following simple example with a graph with no edges, the result is as follows: ...
110 views

### Manipulate with plot and images

I have the following code: ...
309 views

### Package for symbolic computation of christoffel symbols and parallel transports in Riemannian geometry, given the metric

I've no knowledge in mathematica (but I do in matlab), but I'd really appreciate if someone could mention what is/are the best and easy to learn mathematica package(s) for symbolic and numerical ...
60 views

### PeriodogramArray or PowerSpectralDensity?

could anyone explain what is the difference between PowerSpectralDensity[data,omega] and PeriodogramArray[data]? When I plot them (starting from the same set of data of course) I get two different ...
71 views

### Matrix iteration failing after second step

I am calculating 11x6 matrix using different logics as in below code. Problem is in Do loop in below code where I have two different criteria to update matrix "fd". I am expecting logic in IF which ...
160 views

### Plot a data of four dimension

I have a confusion recently about the visualization of data.the data you can get here.The construction of data is four dimension,like as {x,y,z,color},this is my current solution. ...