11
votes
3answers
354 views

Does AbsoluteTiming slow the evaluation time?

I've started using AbsoluteTiming to discriminate between similar function constructs, but I sometimes feel like it takes substantially more time to evaluate a ...
11
votes
5answers
1k views

Fastest square number test

What is the fastest possible square number test in Mathematica 7, both for machine size and big integers? I presume in version 8 the fastest will be a dedicated C LibraryLink function.
10
votes
2answers
347 views

How do I get Mathematica to return a function call unevaluated?

How do I get Mathematica to return a function call (conditionally) unevaluated? I expect this may use the slightly-mysterious Hold function. As a toy example, ...
10
votes
4answers
254 views

Efficient way of identifying the indices of first occurrences

It seems to me like identifying the first occurrence of unique elements should take about the same amount of time as it takes to delete duplicates. My data sets are much larger than this (...
10
votes
3answers
200 views

Returning multiple results from a LibraryLink function

What is the best way to return multiple inhomogeneous results from a LibraryLink function? Imagine that the result of a single computation is several tensors of different dimensions and several ...
10
votes
1answer
263 views

Why does Mathematica fail to series expand this simple expression?

I wanted to expand the function $(x+2)^{x+2}$ around $x = -1$, that is, using Series[(x + 2)^(x + 2), {x, -1, 2}] and Mathematica returns the same expression. ...
10
votes
4answers
2k views

Why does Mathematica struggle with solving this equation?

Consider the evaluation of the following expression In[20]:= Reduce[ 1000 * 1.0609^t == 1500, t] ...
10
votes
2answers
1k views

Did Mathematica 9 remove some previously available stylesheets?

Did Mathematica 9 remove some previously available stylesheets? If so, how can I customize a currently available style sheet to be like a previous one or get previous version's stylesheet back? I ...
10
votes
4answers
2k views

Plot columns of table if some condition is fulfilled

I have a table with data, for example MT = {{1, 80.3, 1, 4, 68}, {2, 80.5, 1, 5.5, 102}, {3, 80.0, 0, 4.2, 78}, {4, 80.4, 0, 3, 17}, {5, 80.2, 1, 5, 180}}; ...
10
votes
3answers
831 views

Derivatives (divergence, gradient, curl) of interpolated 3D data

How can I calculate a vector derivative (i.e. divergence, gradient, curl) of interpolated data? For sample data, you can use: ...
10
votes
1answer
502 views

Visualize cluster distances in DendrogramPlot

I want to perform a cluster analysis using the HierarchicalClustering package. Is there a way to display the inter-cluster distances in a dendrogram plot? An ...
10
votes
1answer
195 views

Unexpected behavior of Compile, Return and ;

Could somebody explain why test = Compile[{{x}}, Return[x]; ]; test[0.] returns ...
10
votes
2answers
1k views

CUDA and GPU hardware and compatibility questions?

We have iMac desktops and have just begun to parallelize computations across them see: Wolfram Light Weight Grid and parallel computing. This still does not look like it will give us the performance ...
10
votes
6answers
1k views

2D Gaussian distribution of squares coordinates

I would like to imitate the structure of this great painting from Ellsworth Kelly in Mathematica. Yet with all the colored squares in Black and the beige one in white. Below is what I have wrote to ...
9
votes
1answer
384 views

How to solve a stiff nonlinear second-order ode?

I want to solve a nonlinear second order ODE as an initial value problem (IVP). Unfortunately, for certain values of first derivative at starting point I get a stiff-problem. I tried to overtake this ...
9
votes
4answers
324 views

Finding a point from a set of contours such that it is nearest to a given point

I have several contour lines and one point. How can I find a point in one of those contour lines which is nearest to the given point? ...
9
votes
1answer
122 views

Named string patterns in Alternatives, why does it depend on order?

When using the same name for part of patterns inside Alternatives how come it behaves differently for strings than in normal patterns? ...
9
votes
3answers
1k views

Guidelines on giving readable names to variables [closed]

I know that one cannot use underscore to a variable name, like degree_of_The_First_Polynomial. But for a long variable name, it ...
9
votes
3answers
236 views

substitution rules excluding subscripted variables

Suppose I have an expression containing p,Subscript[p,1],Subscript[p,2],etc. I want to ...
9
votes
5answers
293 views

How can I remove matching sublists from my list?

I want to use DeleteCases (or any appropriate function) to remove elements of a list, which in turn are lists of fixed size. The rule I wish to apply is that any ...
9
votes
1answer
247 views

PlotMarkers doesn't inherit PlotStyle when first argument to Graphics isn't a list

Could somebody explain, why Circle does not inherit the PlotStyle of the plot when used as ...
9
votes
0answers
366 views

How to improve these WASD + mouse look 3D controls?

Insipred by this question and the corresponding answer I've written a code for full-screen exploration of 3D scenes using standard WASD and mouse look controls. Here it is. ...
9
votes
1answer
147 views

Algorithm used by IsomorphicGraphQ

I'd like to know which algorithm is used to test if two graphs are isomorphic?
9
votes
2answers
765 views

Coloring each face of a Cuboid with a different color

Is there a way to color each face of a Cuboid with a different color? I looked in the help but couldn't find anything. I found this Coloring the faces of a 3D ...
9
votes
1answer
237 views

How do I determine astronomical transit times?

Mathematica, through the "legacy" Scientific Astronomer package, used to have the ability to easily determine accurate transit times of astronomical objects simply, with ...
9
votes
1answer
514 views

Efficient export of complex graphics to PDF

So I have 2D plot, made with DensityListPlot. Mathematica just cannot export them properly to PDF, so what I want to do is 1) export the plot itself, without axes, labels, etc, as a jpg image, and 2) ...
9
votes
5answers
270 views

How can I highlight one function in the Plot of a list?

I've got a Plot of a list of functions from this previous question of mine. ...
9
votes
1answer
147 views
9
votes
3answers
3k views

Expressing a decimal as a fraction in lowest terms

How can I express a decimal such as 0.1845095405274387 as a fraction in its lowest terms?
9
votes
1answer
657 views

CUDALink not working on Mac OS X

On my MacBook Pro, I have a CUDA enabled video card, yet Mathematica does not seem to recognize this. For example, following the CUDALink Setup, I get ...
9
votes
2answers
412 views

Restrict Locator to a certain graphic inside Manipulate

I would like to restrict the Locator inside Manipulate to a certain graphic. For example if I display two graphs, I would like to be able to click on the right one and use this information in other ...
9
votes
2answers
453 views

Shaping/simplifying equations in a certain way

A problem I am occasionally facing is to simplify an equation not to it's shortest form but to a form that is simple by other means. Often, this is grouping the term according to certain functions, ...
9
votes
4answers
560 views

ParametricPlot3D output without the meshlines

Caveat: Mathematica version 3.0. if (or when) it matters. I define a 3D-object with ParametricPlot3D, say, the following: ...
9
votes
8answers
490 views

Adding elements to a collection of lists

I would like to add element a at the start of a series of lists. For example I have a collection of lists called ...
9
votes
3answers
429 views

How to format numbers with at least one figure after the decimal point

I'm searching for a way to get Reals formatted with at least one figure after the decimal point. So e.g. 3. should be printed as 3.0 and ...
9
votes
3answers
243 views

Splitting a list in which figures vary from negative to positive

Consider the following list: data={4078, 256, -1266, -388, 1290, 1368, 1446, 1524, 2}; I would like to split any kind of such list always, when figures turn form ...
9
votes
2answers
303 views

Align Array Plots

I have two ArrayPlots that I would like to align but my "tweaking" failed yet. I would like each "row" to be aligned. ...
9
votes
1answer
375 views

Mathematica implementation of Earth Movers Distance?

Has anyone implemented in Mathematica the Earth Mover's Distance (EMD)? A concept dating back to Monge 1871, used to compare histograms and images, e.g., the CIEDE2000 Color Difference algorithm. ...
9
votes
4answers
271 views

Make a ragged list rectangular by trimming instead of padding

I have a ragged list ragged = {{a,b,c,d,e},{x,y,z}} that I would like to trim (on the right) to be rectangular. The desired result is ...
9
votes
2answers
915 views

Labels and tickmarks inside Frame

Is there a way to force Plot and related functions to place the tick labels inside, rather than outside a frame? For example, consider, ...
9
votes
3answers
345 views

Problem when defining variable in Mathematica

I'm trying to run this: domain := {n, 0, 10}; Plot[n, domain] but it doesn't work. Instead, it generates the message ...
8
votes
1answer
85 views

Possible Bug in ProbitModelFit when used in a Dataset

Since upgrading to Mathematica 10 on Mac OSX I have come across a number of instances of this error, which occurs using Probit and Logit model fit. A bit of googling show this is something to do ...
8
votes
1answer
279 views

Generating high quality charts in Mathematica for use in LaTeX and Word

I frequently have a probelem using my charts in reports because the text (axes labels and tick marks) look low resolution (fuzzy). When I export my charts, i export them as PNG files. Unless I'm ...
8
votes
1answer
140 views

AndersonDarlingTest and DistributionFitTest Leaking Memory

I believe AndersonDarlingTest and probably all other tests are keeping a copy of data somewhere and not freeing it: ...
8
votes
4answers
298 views

Numerical instability in cosh and sinh - integral functions [duplicate]

I'm trying to calculate the function: CoshIntegral[x] Sinh[x] - Cosh[x] SinhIntegral[x] Unfortunately Mathematica seems to hit a point (x~20) and things become ...
8
votes
4answers
287 views

Generate PrimePower counting function

Is there a way to generate a counting function for prime powers - i.e. to create a similar function to PrimePi, but including prime powers. The following will, of ...
8
votes
0answers
108 views

Esc-esc for special characters and autocomplete in Mathematica 9 [duplicate]

I recently upgraded to Mathematica 9 and have noticed a slightly annoying behavior that I was looking to remedy. In the past I would type special characters, e.g. ...
8
votes
2answers
221 views

PlotRangeClipping not working correctly with small ImageSize and PDF-export

Although Mathematica has some nice plotting capabilities, there are some things which are annoying me: I like to export a Graphics oder Plot to PDF for use in $\LaTeX$. I like to a have an ImageSize ...
8
votes
4answers
378 views

Partitioning a list by recursion (Programming Paradigms via Mathematica (A First Course))

I am working through the course Programming Paradigms via Mathematica. One of the homework exercises for the section Recursion I: Passing the Buck is as follows: Use recursion to partition a ...
8
votes
2answers
252 views

Correct way to generate large data sets (i.e.forward yield curve )

I would like to generate a set of forward yield curve matrix of size 1000 x 100. First I defined my SparseArray of 1000 x100: ...

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