All Questions

134 views

What's wrong with my implementation of SquareFreeQ?

This was a question I had last month: Part A: Looking at the exponent of each of the elements in the list, FactorInteger and using ...
289 views

Plot the solution complex transcendental equation

I'm trying to plot an implicit function satisfying a complex transcendental equation. The code is the following: ...
70 views

What's wrong with the following Plot in Manipulate?

I try to show the convolution of a step function and a triangle function is smooth with the following code: ...
515 views

Interpolating data with a step

Suppose I have some data with a step in it: data = {{1, 1}, {2, 2}, {3, 3}, {3, 4}, {4, 5}, {5, 6}}; Interpolation will complain about this and not give you an ...
165 views

BezierCurve in EdgeShapeFunction fails when used on multiedges graph

I would like to create a network graph with curved edges. To do this, I wrote this function: ...
247 views

Formatting plot of symmetric points differently to asymmetric points

From an array of numbers, I would like to determine (and then colour appropriately) which points are symmetric about a given axis (here, $x = 1/2$), and which are not. For example, form this: ...
231 views

How I can make a menu with different graphs with modifiable parameters?

I want a user friendly window in which to have a menu where you can choose the chart you want to display, in which you can move parameters in order to note the width or height of the chart, but I try ...
1k views

Convert Integer to Real

Is there a preferred way of converting an Integer to a Real? What I'm using at the moment is ...
154 views

NDSolve finding solution when it shouldn't

NDSolve in mathematica drives me crazy and I'm seriously thinking about switching to Matlab because of strange bugs I run into. ...
118 views

How to use ProbabilityDistribution for a posterior expression [duplicate]

I am performing a Bayesian updating on a Lognormal prior. After combining the prior and likelihood and dividing by the normalization constant I get the following expression as the posterior: ...
86 views

Plot with non-standard domain

I have data {x, y} where x starts at -25 degrees and goes up to +25 degrees in 1 degree steps, and then comes back down to -25 degrees in 1 degree steps again. I ...
647 views

Newton-Raphson Method and the Van der Waal Equation Coding question

So I need to find Specific Volumes using the Newton Method from the Van der Waal equation over a change of constant Temperature but variant Pressure. I have been able to make a list of however many ...
671 views

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139 views

How to plot complex values given by Solve

Update Solve[N[Table[BernoulliB[n, z], {n, 10, 10}] == 0]] ...
146 views

bulk initialization of associative array/hash implemented with function pattern matching?

I see that we can do associative arrays in Mathematica using functions that have implicit pattern arguments, as in ...
187 views

Adding labels on ArrayPlot and coloring rows

I need to add lables on the right from ArrayPlot for each row and color the black square of each row depending on values from two list. Color list has a numbers in some range and should be mapped ...
38 views

Use Output as Input [duplicate]

I have this function which as a result returns a point ...
230 views

Why is D[a[b][c],a[b]] equal to 1[c]?

Background: I had the same issue as described here, and I went to extend Mr.Wizard’s code such that a[b][c] would be shown as $a_b^c$. Issue: To my surprise, ...
527 views

How do you get a list of filenames from a URL?

How would I get a list of filenames available at a URL? For example, list the files at: http://www1.ncdc.noaa.gov/pub/data/cmb/drought/weekly-palmers/2005/
44 views

How to fit ODE's coefficient, just like using NMinimize [duplicate]

I want to fit ODE's coefficients to a model. I tried using NMinimize, but it seems it does symbolic instead of numerical calculations. ...
790 views

Connect to remote Ms-sql Database

I can connect to the local Database(installed in my system) from Mathematica via ...
395 views

Flow in pipeline graph

I have pipeline directed graph which has one source and several sinks ...
210 views

What is the formula for this numerical series?

I'm developing a questions game. My goal is that the score for each correct answer will increase as the user answers more questions. Initially there are 15 points for each correct answer. Every 4 ...
160 views

How to increase the size of the dot produced by OverDot[]

As the title says, I want to find a way to increase the size of the dot produced by OverDot[]. Here is a simple code ...
2k views

Profiling from Mathematica

I've always wished I could do some profiling like you get in Wolfram Workbench, but directly from Mathematica, without using or having Workbench. If it is possible, how can I do it?
483 views

10bits per rgb / 1024 shades of gray?

Can we display 10 bits per rgb in Mathematica? I'm using a quadro card and 30 bit monitor and can get a smooth gradient using Psychtoolbox in matlab. The following Mathematica should produce a bar ...
187 views

Differentiating a Cumulative Distribution Function which has a discontinuity at $0$

I want to take the derivative of a distribution function which has a discontinuity at $0$. Here is the function: ...
164 views

Compute coefficient of Generating function

Given a generating function $F(z)$, is there any way to compute the coefficient $a_k$ of $z^k$ by Mathematica? One method is to calculate by the equation $\frac{F^{(k)}(0)}{k!}$. However, this ...
734 views

Derivative from the left and right

I am currently trying to write a script that takes a curve $C$, a starting point $p$ and a direction vector $\vec{v}$ and calculates the path of a beam starting at $p$ in direction $\vec{v}$ when it ...
136 views

Assumptions in mathematica when Symplify on Log[Exp[a/b]]

In mathematica 9.0: This: Assuming[b > 0 || b < 0, Simplify[Log[Exp[a/b]]]] yields: a/b However, this: ...
263 views

Compatibility issues for Combinatorica package

I am trying to use the Combinatorica package in a Mathematica version 9 in the following code : ...
249 views

I want to add two matrices, the first one containing a 2D vector at each position the other one a list of 2D vectors. The 2D vector from the first matrix should be added to each of the 2D vectors at ...
961 views

Customizing & finding intersection points in polar plot

I want to verify a theory stating that a golden mean spiral plotted on a polar graph will have intersection points at specific values. There should be 8 concentric circles, each at the same ...
252 views

Extract date from a not well-formed string

Is there a way to robustly extract date and time from a text? Say for example: ...The event will be held on 17/10/2013 at 3:30 PM in the room 121 and everyone is welcome... should return: ...
57 views

Parallelizing an associative binary operation

I have an associative binary operation '.', which I often use in this sort of way: result = expr1 . expr2 . expr3 . expr4 The ...
185 views

Plotting Laplace's equation on an infinite domain

I am trying to plot my solution to a Laplace equation on an infinite domain. However, when I try to plot it, Mathematica just runs with nothing happening. ...
202 views

Simplifying expression with patterns (Replace)

Q1: I need to simplify some algebraic expression, according to particular pattern, namely: \begin{equation*} x^m = \left\{ \begin{array}{ll} 1 & \text{if } m \text{ is even} \\ x & \text{if ...
137 views

Histogram For Non-Numerical Data

I have a non-numerical data, let say data = Table[RandomChoice[{0.2, 0.3, 0.25, 0.15, 0.1} -> {"A", "B", "C", "D", "E"}], {500}]; and i want to make a ...
303 views

Organise a graph's vertices into levels

I would like to organise a graph's vertices in levels. Consider ...
91 views

How to capture implicit fails in Plot or Show? [duplicate]

How can I make a construct similar to C++ functions: try{} catch{} I want to use it to avoid showing a lot of errors in the plot area when for example one of the ...
4k views

How do I extract a number from a string?

I want to extract the number from an alphanumeric string. This is what I tried: StringTake["thiru3", {6, 6}] The result I got is ...
88 views

Whitespace after number subscript

When I write something like this: (Subscript[x, 0], f(Subscript[x, 0])) I get some undesirable whitespace after each of the ...
829 views

How to find an asymptote of a logarithmic curve

An exponential decay curve has been plotted asymptoting at approximately x=30 (correct for what I am looking at) How can I find the exact value from the curve? I was hoping to be able to use ...
114 views

Memory usage of timeseries - lists of {Integer32, Real32}

A list of {Integer32, Real32} items in Mathematica seems to use 12-times as much memory than the C equivalent array of structs. ...
205 views

Plot Ticks disappear when combining Plot with Graphics

I'm attempting a simple Plot that I want to add asymptote markers to: ...
855 views

Syntax question regarding Triple Integrals in Mathematica

Integrate[1, {z, 0, 5}, {x, -Sqrt[ 9 - y^2], Sqrt[ 9 - y^2]} , {y, -3, 3}] 60 Sqrt[9 - y^2] How comes I am not getting a number for my final answer? This ...
273 views

Product of edge weights in path

I need to calculate the product of graph edge weights on the path taking into account edge direction. I.e. for graph ...
206 views

Border on part of ArrayPlot

I need to outline with border the group of cells in ArrayPlot. More precisely in my case I would like to outline all blocks of two black squares in the following line. ...