-3
votes
2answers
528 views

Optimization of a portfolio of stocks

I would like to use Mathematica to perform an optimization of a portfolio composed by 10 stocks. I did the first part to compute yields and expected yields, but I don't know how to finish the ...
-3
votes
1answer
178 views

Gamma Incomplete Function representation in Mathematica and Matlab

I am confused about Gamma Incomplete function calculation in Mathematica and MatLab: For example, in Mathematica: Gamma[5,3] = 19.56 But in MatLab: ...
-3
votes
1answer
118 views

Mathematica output in ASCII or larger text size for the output?

I am trying to read the output of this code that has crosses, circles and spaces. For some reason, the output is in very-very small alphabets so I would like to get it in ASCII and/or in larger ...
-5
votes
1answer
1k views

Determine the 2D-Fourier transform of an Image

I am new to Mathematica and using Version 8.0. I want to calculate the 2D-Fourier Transform of a digital image and see its Magnitude and Phase Spectrum, and reconstruct it.
-7
votes
1answer
85 views

Simplify looks ugly [closed]

I use Simplify mostly to make expressions look neat. However, Mathematica often does not produce expression in, what I consider, the optimal way. Look at this: ...
14
votes
2answers
137 views

Symbolic derivatives are being calculated numerically

Just found the following while debugging a problem. Mathematica is calculating the derivative of IntegerPart[x] in some odd way: ...
14
votes
2answers
213 views

Upon PDF export, edgeless rectangles do not tile perfectly, and corners may be cut. Is this a bug?

Exporting the following as a PDF file Graphics[{ {Red, Rectangle[{0, 0}, {1, 1}]}, {Green, Rectangle[{1, 0}, {2, 1}]} }] does not produce perfectly tiled ...
14
votes
1answer
304 views

Why does LogLinearPlot sample its argument outside the specified domain?

I experience a weird bug in the function LogLinearPlot. If the input is an interpolation function, such as the one created like this, ...
14
votes
4answers
722 views

Converting a large floating-point number to a single-line string

When I feed a large (or small) enough floating-point number to ToString, it produces a two-line string, with the first line containing only the exponent of 10: ...
13
votes
1answer
121 views

Possible to draw an Item in a Grid with only 3 sides of a Frame?

I'm trying to draw a Grid of characters where some of the characters have Frame lines on 3 sides. For example: ...
12
votes
4answers
337 views

Equivalent Nested Loop Structure

Consider the following examples: ...
12
votes
4answers
739 views

Evaluation of a triple sum does not finish in reasonable time

I'm trying to compute the following triple sum, but no result is produced within a reasonable amount of time. What to do? ...
12
votes
1answer
169 views

How to get an adaptive frame which fits auto-wrapped text? [duplicate]

When using the built-in Debugger, the breakpoints and the current step will be framed looks like this: My favorite part is, those frames are adaptive to the text when window width changing makes it ...
12
votes
2answers
276 views

Using uniform coloring in MatrixPlot

I have a rectangular matrix, which is m-by-10. Each element is either 0 or 1. I would like 0 to correspond to white elements, and 1 to red elements. This works ...
12
votes
4answers
2k views

How do I draw a DensityPlot in polar coordinates?

I am trying to plot $J_m(\chi_{mn} r) \cos(m\phi),$ where $J_m(\chi_{mn}) =0,$ as a DensityPlot in polar coordinates (solution to 2D wave equation in polar ...
12
votes
3answers
259 views

Arguments to If[] are not evaluated

I got bitten by the following: f[x_] := 3*x; g[x_] := If[Log[f[x]] < 0, f[x], 0]; g[x] Out[11]= If[Log[3 x] < 0, f[x], 0] where I thought the call to ...
12
votes
1answer
233 views

Effects of single-point and multi-point calls of Point on plot range

Several Graphics primitives are listable. For instance, Point accepts lists of coordinates so that multiple calls to Point are ...
11
votes
1answer
310 views

Generating Gelfand-Tsetlin patterns

I am doing some research on some combinatorial object called GT-patterns. They are generated from three parts of data. Two integer, partitions (sequences of weakly decreasing numbers), $\lambda = ...
11
votes
4answers
559 views

How can I return a Sequence?

Recently I had the need to redefine a certain symbol in my init.m so it would be automatically omitted from any lists it appears in. I decided to redefine it to an empty sequence, e.g. ...
11
votes
3answers
401 views

Labeling plots without evaluation

This is my first question here so please excuse my mistakes. Let us consider a rather contrived example: ...
11
votes
4answers
376 views

Grid - Item - Alignment to decimal problem

I've run into a Grid layout problem for which I don't know a solution. I want to specify alignment to a specific character such as a decimal and an ...
11
votes
2answers
237 views

can a ColorFunction have side effects?

Can anyone explain this (to me) odd behavior. If I run this code once (fresh kernel) it works as intended. ...
11
votes
1answer
1k views

What method does NDSolve use for solving PDEs?

What is NDSolve's mode of operation? I use it to solve partial differential equations and never gave it too much thought. Recently, I came across this question. ...
10
votes
1answer
184 views

How to suppress Tooltip in built-in templates?

...or maybe switch the message. But I will be happy with no Tooltip at all. I've naively tried with ...
10
votes
2answers
185 views
10
votes
0answers
151 views

HorizontalGauge causes problem with ScalingFunctions -> “Log”

I am trying to use HorizontalGauge[Dynamic[expt], {0.1, 100}, ScalingFunctions -> "Log"], i.e. a gauge with a logarithmic scale. This creates an error, a graph ...
10
votes
2answers
145 views

Return partial result when MemoryConstrained aborts NDSolve

I use NDSolve to solve a large set (~400) of coupled ODEs. Sometimes, the memory (~4GB) gets filled up, and my computer becomes impossible to work with, because it ...
10
votes
5answers
573 views

How to plot rectangles aligned by their center?

Supose I have a rectangle which area is $x^2$. In some cases I may not know what is the size of each side, for $x=12,$ we have several possibilites: ...
10
votes
1answer
328 views

How does Mathematica know my location?

On the AstronomicalData page in the online reference, it says for AstronomicalData["Sun", "NextRiseTime"] that it finds the ...
10
votes
2answers
527 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 ...
10
votes
2answers
228 views

Make a button that evaluates a function over and over

I would like to have a command "RedoButton" which would make a button (or whatever control is suitable) that when clicked would print the value of a certain function over and over in the same place. ...
10
votes
1answer
202 views

Rounding problems inside InputField

Consider the following InputField InputField[Dynamic[h2, If[# === Null, h2 = h2, h2 = Round[#, 0.001]] &], Number] The ...
10
votes
4answers
376 views

Extracting equations from Piecewise expressions

Say I have a PDF: PDF[LogNormalDistribution[1.75, 0.65], x] Calculating it, Mathematica gives me an expression that looks like this: I want to extract the ...
10
votes
2answers
290 views

Conditional Gathering of lists

Just need a little help with the GatherBy / SplitBy function(s). I have a list of random numbers here: ...
10
votes
2answers
492 views

Creating randomly oriented planes

I would like to create randomly oriented planes. This is how I'm attempting to do that: I create a 2 random unit vectors, $\mathbf{v}_1$, and $\mathbf{v}_2$, in the $x$-$y$ plane I assume that if I ...
9
votes
1answer
191 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}}; ...
9
votes
5answers
449 views

How to choose three points on the circle so that the triangle is not a right triangle?

I want to choose three points $A$, $B$, $C$ has integer coordinates on the circle $$(x+2)^2 + (y+1)^2 = 25$$ so that the triangle is not a right triangle. But I can not. I tried ...
9
votes
6answers
390 views

Performing Computations on Sets

I would like to find a permutation of $\quad S=\{\frac{1}{10}, \frac{1}{2}, \frac{4}{7}, \frac{3}{5}, \frac{2}{3} \}\quad$ that maximizes the sum of theses elements raised to unique powers: ...
9
votes
0answers
133 views

Compile not correctly initializing a variable defined inside Module

In the following example, inside the minimumX's Module, x is initialized to 1, but the ...
9
votes
1answer
207 views

Why is ReplaceAll behaving like this?

I'm learning to use the ReplaceAll function and I found the behavior of which is quite confusing. For Sqrt[f[x, y]] /. f[___] -> u Mathematica returns ...
9
votes
1answer
576 views

Functional programming and Do loops

I'm writing a Monte Carlo simulation. I'm using a Do loop to create the different simulations, iterating over different ...
9
votes
1answer
267 views

Defining Tags in Reap

I am trying to use Sow/Reap to replace Append in my code. The problem is that I need to ...
9
votes
3answers
770 views

BarChart frame labels

This barchart was tricky to style, and I had to resort to the legacy BarCharts`package. Any ideas how to omit the labels from the bottom edge? Ideally I'd also like ...
9
votes
1answer
212 views

What default theoretical distribution does Mathematica use in PearsonChiSquareTest?

I used Mathematica's function PearsonChiSquareTest to test whether the data were drawn from a normal distribution. As in the reference, I expected Mathematica to compare the result to a normal ...
9
votes
5answers
230 views

Fill out blanks with a upcoming number in a list?

I have a bunch of arrays looking like this: {"", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", "", ...
9
votes
2answers
926 views

InterpolationOrder for ContourPlot

How do I acheive something like InterpolationOrder in ListContourPlot for ContourPlot? My ...
9
votes
4answers
1k views

How to sum up subelements of a list of unknown length

I'm simply looking for the {}+{} function for sublist elements of a list: (Parallel sums of elements) ...
9
votes
3answers
718 views

How do I change the Font in BarChart Legend?

Just wondering if anyone knows the proper Syntax to change the Text properties in the BarChart's ChartLegend. I cannot seem to figure out how to get Style[] to apply. Here is an example: ...
9
votes
4answers
381 views

Permutations[Range[12]] produces an error instead of a list

This input: Permutations[Range[12]] Results in this (error) output: ...

15 30 50 per page