Top new questions this week:

A bug in Integrate

Integrate[(1 + 16 Tan[2 x - y]^2)/(1 + 4 Tan[2 x - y]^2), {x, 0, 2 π}] Mathematica (wrong) output is (tested under versions 8 and 10.0, took ~ 1 minute of CPU time) 10 π The correct value of this ...

numerical-integration calculus-and-analysis bugs

asked by Vaclav Kotesovec 17 votes answered by Histograms 11 votes

What is the FrontEnd?

Can anyone sort out what the Front-End is, how it is structured and what its relationship to the Kernel is. The FrontEnd is mentioned quite often but elusively avoids to be caught and clearly defined. ...

front-end

asked by MathLind 16 votes answered by Mr.Wizard 13 votes

Regime Change Stochastic Process

I would like to simulate an Ito process in which the drift and diffusion terms change after hitting a boundary for the first time. For example, a Geometric Brownian Motion X which has 0 drift and ...

random stochastic-calculus

asked by Shffl 12 votes answered by Sjoerd C. de Vries 9 votes

How to speed up Colorize

I have a list of about 500 images similar to the following: A = Import["http://i.stack.imgur.com/1bV4O.png"] AbsoluteTiming[Colorize[A, ColorFunction -> "AvocadoColors"]] Gives ~ 0.6 ...

performance-tuning image-processing

asked by DarrenM 11 votes answered by bill s 7 votes

Does Mathematica have an equivalent of Python's float.as_integer_ratio?

The Python programming language has a float.as_integer_ratio(x) function which exactly converts an IEEE 754 floating-point number into a numerator/denominator pair of integers. For example: ...

machine-precision

asked by David Zhang 10 votes answered by Guess who it is. 15 votes

Does Mathematica have an equivalent of C's nextafter?

In C (and many other programming languages), there is a function double nextafter(double x, double y) which takes two (IEEE 754) floating-point numbers and returns the next representable ...

numerics machine-precision

asked by David Zhang 9 votes answered by Michael E2 5 votes

How can I make FilledCurve smoother?

In How can I generate and randomly assign color to annular sectors? J.M. showed an interesting way to create a sector graphic using FilledCurve. Unfortunately it was marred by an inferior rendering ...

graphics options undocumented splines rendering

asked by Mr.Wizard 9 votes answered by Mr.Wizard 9 votes

Greatest hits from previous weeks:

How to find all the local minima/maxima in a range

I want to find : all local maxima in range all local minima in range From those points I can interpolate and combine functions upper and lower boundary. What I am really interested in, is the ...

mathematical-optimization peak-detection

asked by Margus 50 votes answered by Daniel Lichtblau 51 votes

A one line proof that one is zero using Mathematica 10

a = (Sqrt[2] + 1) (Sqrt[2] - 1) - 1; {a/a, Simplify[a]/a, b/b == Simplify[b]/b} {1, 0, True} This one line "proof" that one equals zero is disturbing (and could possibly lead to wrong results ...

evaluation

asked by Grégoire Nicollier 11 votes answered by Szabolcs 24 votes

Can you answer these?

Using an arbitrary area bounded by lines for PDEs?

I have a set of lines I pulled from an image that make a closed loop, pretend it's a unit square for reference. Is there a way to use such an arbitrary region for solving PDEs, and is there a way to ...

differential-equations image-processing

asked by PCK 1 vote

Map an Argument to a list of functions

I want to "map" an argument to a list of functions. Here is the concrete Problem. I generate a list "Messungfit" of functions: Messungfit = Table[LinearModelFit[Messungenplot[[i]], {1, x}, x], {i, ...

list-manipulation map

asked by mcocdawc 3 votes

Can Mathematica poll the dimensions of the individual monitors of its host computer?

The command SystemInformation["Devices", "ScreenInformation"] returns the screen area in the monitors connected to its host computer: {{"ScreenArea" -> {{65, 3200}, {24, 1080}}, ...

display system hardware

asked by episanty 4 votes