All Questions

354 views

refer to result of cell above current cell?

% allows to refer to the result of the preceding calculation (preceding in time) but this seems not necessarily to be the cell just above a given cell. How can ...
260 views

We are running a Windows 7 machine with Nvidia GTX 770. According to this reference GPU Hardware: CUDA for Mathematica 9 is not supported on that hardware. Is there any way to get it running? ...
103 views

How to “reversely” replace definitions?

I have the following problem at hand. 1.) I have a list of definitions like ...
303 views

What is the most elegant way to specifiy a start case for recursion?

When writing recursive code that computes the least value at which a condition is true and various other scenarios it is often necessary to specify a base case. What I have done to supply this is ...
120 views

Differentiating a Dot Product

I apologize if this type of question has been asked before, but a preliminary search turned up nothing. I would like to differentiate dot products. For example, consider taking a derivative with ...
292 views

Creating a function with integral zeroes of the 0th, 1st, and 2nd derivatives

I would like to be able to randomly generate functions, each of which satisfies $f : [-10, 10] \rightarrow [-10, 10]$ All the zeroes, critical points, and inflection points have an integral ...
239 views

Strange behavior when using Row with packed arrays

Bug fixed in 10.0.0 Today I lost a lot of time with a strange behavior and I narrowed it down to this small piece of code: ...
135 views

Result of NIntegrate ploting to list

I've been working on a project where I need to make two Plots. Those plots are of the form: ...
239 views

How to define function that can change patterns

Given time series data as follows: data = {{{2011, 1, 13}, 10}, {{2011, 2, 14}, 17}, {{2011, 3, 15}, 20}, {{2012, 1, 16}, 30}, {{2012, 2, 17}, 40}}; ...
123 views

Anchor Manipulate Controls to Edges of Content

I'm running into an issue with arranging Manipulate controls and a dynamic module around the content pane of the Manipulate. For example: ...
284 views

Running out of variables

I am running symbolic calculations with Mathematica. Simplification of algebraic expressions is an important part of them as very often final results can be simplified considerably. Typically my ...
44 views

mathematica 9.0 starts with 2 kernels that take up 2 licenses [duplicate]

Mathematica 9 starts automatically with 2 MathKernels which in itself is ok but they also count as 2 licenses and that is definitely not OK. It halves our available concurrent network licenses. Is ...
130 views

How to solve a ParametricNDSolve issue when the system seems to be stiff?

I have a problem with ParametricNDSolve[]. Mathematica gives the warning that a stiff system is suspected. I have varied the methods but unfortunately I was not ...
269 views

Partitioning time series data in sublists by their duration

I would like to do calculations on irregularly sampled time series data at intervals - for example on an hourly basis - rather than over the whole time series. The entire dataset is split up by time ...
164 views

Choosing PrecissionGoal and AccuracyGoal for decomposed integral with NIntegrate

Assume I have a complicated integral $I$ which can feature all kinds of difficulties like infinite interval, rapidly oscillatory integrand, integrable singularities and numerically almost singular ...
137 views

Trying to find the best Pade approximant for a given numer of terms

Let suppose that I have a function $f[x]$ I want to approximate using a Pade expansion and that I decide what would be maximum number of terms to be used. Is there any way with Mathematica to find ...
275 views

Extracting frequencies with Fouriertransformation

I know this question came up so many times, but after browsing through many of the threads, I'm still not sure, if I'm doing it correctly with my dataset, so I'll give it a try. If have some sample ...
349 views

Find Chebyshev center of a region by optimization

Let's consider a region like this: The aim is to find the "Chebyshev center" of the region. By using the polygons, one can approximate the perimeter of region by an $n$-gon ($n$ is large enough). ...
1k views

Shuffle product of two lists

I want to do the following: I have two lists {a_1,...a_n}, {b_1,...,b_n} and I would like to build now all shuffles out of this. This means all unions of these ...
132 views

Finding the InverseFunction of a polynomial function restricted to an interval [duplicate]

I want to calculate the inverse of f[x_] := 1/2 - (x (4 x^2 - 9))/12 /; -1/2 <= x <= 1/2 f[x] is monotonic inside ...
129 views

Creating a function as a table of derivations

Suppose I have function, which is in fact a list of $n$ functions with $n$ parameters f = {#1 + #2^2 + #3^3, #1^2 + #2^3 + #3^4, #1^3 + #2^4 + #3^5}& I want ...
366 views

Find nearest distance of an interior point from perimeter

By definition, the interior point is a point inside an arbitrary region like this: In picture above, $y$ is an interior point of region. My question is how to find the distance of an interior point ...
166 views

Why Refine does not simplify Cos[2*Pi*FractionalPart[1/2*(i + j + k)]] to $(-1)^{i+j+k}$?

I am obtaining in Mathematica: Cos[2*Pi*FractionalPart[1/2*(i + j + k)]] We know that for $i, j, k$ being positive integers this expression after simplification ...
121 views

Expressions with Boolean variables and simplification

I have some familiarity with Mathematica, but have no experience with any Boolean computation. Suppose we have the Boolean formula $(x_1 \lor x_2) \land (x_2 \lor x_3)$. This can be simplified by ...
272 views

Error Function Integral (Erf)

Any idea how to solve analytically this integral Integrate[(a Erf[a Sqrt[b/(a^2 + b)] c])/(a^2 + b)^(3/2), a] I tried substitution u=a^2 + b, but it didn't work. ...
203 views

What is an elegant way to aggregate two cash flows

When modeling a swap contract a common operation is to sum up two cash flows producing a resulting cashflow with netted amounts in the highest granularity of the two initial cash flows. What is a ...
127 views

How to display output as symbols?

I have this piece of code which populates a matrix following different rules depending on row and column number: ...
907 views

Solve for variable in integral limit when using NIntegrate

I am trying to solve for a variable which appears in the limits of an integral, rather like in the following; ...
268 views

Sample code for generating mosaic images doesn't work

I'm reading the blog on mosaics by Theodore Gray. I tried the first example: ...
103 views

Why is ^^ff not the same as ^^ToExpression[“ff”]?

I want to convert a hexadecimal string to a decimal (base 10) number: 16^^ff 16^^ToExpression["ff"] The 1st line returns the correct answer of 255, while the 2nd ...
123 views

I fed this inequality into Wolfram/Alpha: Mod[-1 + 2^(1 - IntegerExponent[2 + 2 x, 2]) 3^ IntegerExponent[2 + 2 x, 2] (1 + x), 1 + 2 x] < 1 + 2 x, and got ...
312 views

Kinetic Friction in Mathematica, weird behaviour

I found the behavoiur of Sign function weird in the code below. when $T=10$ ...
93 views

Optimizing a bubble art code [duplicate]

Based on that website I wanted to recreate the same effect using Mathematica but with any picture given by the user. Thus I came up with the following code: ...
499 views

For-loop not working as I expect

I want to do this: When 10 <= t < 130, give t -> 1; When 130 <= t<300, give ...
665 views

Extracting angles from a simple picture

I'm not sure if this is even possible with Mathematica, but I want to extract the angles between all lines in this picture: It consists of $12$ lines, so I want a matrix with $144$ entries. I ...
445 views

FindInstance (and Solve, …) abysmally slow on a fully determined system of linear equations and inequalities: why?

I took a quick look for FindInstance and Solve-related questions but came up empty for the aspect that I am curious about. So ...
123 views

Holding Input Windows

I am creating a Mathematica document which contains a list of proofs in various fields of Mathematics so that I can easily review whenever I would like. First, I create a large set I call 'proofs' ...
1k views

cross-correlation with time lag

I have two lists with some data. a={1,2,3,4,5} b={5,4,3,2,1} Now I want to compute the cross correlation of the two lists with a time lag of 1, like it is ...
138 views

Alternative closed forms for digamma expressions

What commands should I use such that Mathematica / W|A express $$\psi(1+i)+\psi(1-i)$$ exclusively in terms of trigonometric functions?
94 views

Exponential function Integral

I have tried to solve this integral: Integrate[E^(-((a^2 b c^2)/(a^2 + b)))/(a^2 + b)^2,a] Mathemathica is not able to solve it, I have tried the integration by ...
121 views

NDSolve with different function lengths over time

I'm working on a cops & robbers game, and there is one single event that is very very important, the event of catching someone. I'm trying to do when any robber is catched, delete it from the ...
94 views

Why TensorReduce not working here?

I would like to use TensorReduce to work on the tensor contraction $y_{ib}y_{ia}$ (where index $i$ is summed). However, ...
149 views

How to vary thickness of line on the plot? [duplicate]

How to plot the function f(x) so that one part be a thicker line than another depending on the value x? (Curve is efficient frontier - portfolio optimization)
107 views

Return only one numeric solution to equation [duplicate]

Consider a simple plane equation 2x-3y+4z==7 I just want some position vector on that plane. For example, {7/2,0,0} would be ...
375 views

Is Mathematica compatible with primusrun?

I use Mathematica 9 on Ubuntu 12.04 LTS x86 (64-bit). My computer has an Nvidia graphics card, for which I installed primus and ...
76 views

densityplot + world map overlay [duplicate]

I can make a world map, and I can make a density plot, but I can't seem to get them to overlay. Was trying to use Show to overlay: ...
147 views

Exploiting a relation among constants

Say I have two arbitrary real constants $p,q$ that satisfy $p^2+q^2=1$. Is there any way to easily declare this relation in Mathematica? Edit More specifically I have this (among others) expression: ...
123 views

Handling output that was returned unevaluated from a function

When evaluating functions, including those described in this post, how do Mathematica users handle values returned from a function that are unevaluated? For example (based on 1): ...