# All Questions

2k 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 ...
216 views

### Graph subtree with respect to the flow

So let's say we have a TreeGraph: ...
167 views

### Is there a practical way to define a default value for missing keys in an Association?

Clarification Although I may be missing his point I currently feel that Leonid's comments below are misleading. I am not looking for anything that is not already a part of ...
108 views

### Finding self-intersections of a closed curve represented by an interpolation function

I've been trying to find particular simple closed curves on a plane. ...
787 views

### Can Mathematica tell me if a polynomial has all real roots?

I am trying on this polynomial, ...
123 views

### LinearSolve and Krylov Method options

I need to solve a large, sparse, linear system. At some point Method -> "Multifrontal" fails and a bit later also "Pardiso" ...
111 views

### How to synchronize the display of dynamic objects?

I was looking at this question, which asks to keep the orientation of some 3D graphics objects constant (relative to the viewer) while rotating the rest with the mouse. I thought that maybe the ...
616 views

### Flatten nested lists

I have a list as follows lis= {a, {{{b}, {c,d,e}}, {{f}, {g,h,i}}}} which I would like to flatten to ...
172 views

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### The magic square function

There're some matrices that the sum of columns, sum of rows, and sum of diagonals are the same value. Here is an example: ...
237 views

### $3\times 3 = 6 + \bar{3}$ in Mathematica?

Can Mathematica handle this type of algebra, which is used very frequently in e.g. particle/nuclear physics? That is, I want to decompose a product of representations (in $SU(N)$ say) into irreducible ...
225 views

### Suspected bug in Integrate

Bug introduced in 9.0.1 or earlier and fixed in 10.1.0 In version 10.0: ...
74 views

### Is “MaxMessageCount” broken or is its function counter-intuitive?

Behavior remains unchanged through Mathematica version 10.1.0 As noted by kguler the Front End option: MessageOptions -> "MaxMessageCount" does not appear to ...
201 views

### Backslash commands in strings?

I discovered by playing around that Text[DisplayForm@SubscriptBox["\[Lambda]", "k"]] produces the same result as ...
1k views

I noticed that the following line, Image[Table[x, {y, 1, 250}, {x, 30/256, 40/256, 0.02/256}], Magnification -> 1] results in the following image: In the ...
1k views

### detecting the radius of an incomplete circle

I need your help to detect the radius of the blue circle in images like this: . Reading these questions: 1, 2, 3, I figured that this code taken from @halirutan answer to question n°3 could help: ...
269 views

### Working with Java hashmaps from Mathematica

I'm using J/Link to access data from an external Java program. The data are represented as a ConcurrentHashMap (see the official specification here). ...
475 views

### Why do I get a different value when I change the order of integration?

I think the following two-dimensional integrals should be equal, since they both integrate the function over the half plane defined by $t>\tau$. \int_{-\infty}^\infty \mathrm{d}t ...
404 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 ...
176 views

### Integrating a BesselJ integrand to obtain the same result as Maple 16

I would like to check the following integration: Integrate[y*Integrate[1/x*BesselJ[1,x*Exp[I*π/4]]*BesselJ[1,x*Exp[-I*π/4]],{x,0,y}],{y,0,r}] Mathematica 9.0 is ...
511 views

### Is there a way to symbolically invert a piecewise function

I have a piecewise function that is continuous and strictly monotonic, like this: f[t_] = Piecewise[{{t/4, t < 0}, {t/2, t < 3}, {3/2 + (t - 3)*3, True}}] ...
140 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? ...
222 views

### Improving the performance of a package for working with rational functions

As Mathematica gets slow for large symbolic calculations, the cost of putting terms over a common denominator (Together), in particular, gets too high. It occurred ...
1k views

### How to set a zero offset for the frame origin?

I want to set a zero offset for the frame origin. In other words, the horizontal axis should start at exactly the lower bound, instead of having a small offset. For example, in the figure below, ...
350 views

### PlotMarkers don't change colour for different lines

I have a set of data and several function operating on the same data, that I wish to plot together in a ListPlot. I need different ...
241 views

### Have the Random functions changed?

I re-ran a program I wrote for Mathematica v8, now on v9, and it appears to generate different RandomInteger numbers, even though I use the same ...
510 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 ...
303 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 ...
280 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: ...
196 views

### How to define UpValues in a different context from within a package

I'm trying to create a function (in a package) to import a lot of data and create a symbol with UpValues to return specific results about the data. I've got it working fine in a regular notebook, but ...
299 views

### The only usage for the option InterpolationOrder in NDSolve is to be set to All?

We know that changing the option InterpolationOrder in ListLinePlotListPlot3D、...
273 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 ...
793 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) ...
1k views

### RegionPlot (or FillingStyle) using hash lines? [duplicate]

Possible Duplicate: Filling a polygon with a pattern of insets I have a RegionPlot (and sometimes a regular Plot) where I'd like to shade two different parts of it two different ways. Since ...
1k views

### Exporting a Large Multidimensional Sparse Array

I'm trying to export a sparse array from Mathematica to share with collaborators who primarily use Matlab. The sparse array in question is 4 dimensional, (72 x 93 x 94 x 172) with ~4M non-zero ...
231 views

### Leave expression tree formatting the same when a replacement rule is applied

If I type e1 := 3 x + 2 (1 + y) z // TreeForm, I get an expression tree. If I then type e1 /. x -> 3, I get another ...
788 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 ...
1k views

### Is it possible to type equations as text in Mathematica?

I was wondering if I could write an equation, symbolically, but only as part of a text in Mathematica. So I don't want Mathematica to consider anything inside that equation as a variable, nor equate ...
532 views

### Keeping Quotation Marks in Output

I am running into the following seemingly simple problem. I have this code: testphrase="i love you"; input=ToLowerCase[StringSplit[testphrase, Whitespace]] It ...
687 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: ...
697 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 ...
590 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 ...
301 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 ...
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### 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. ...
750 views

### When using GraphPlot with an adjacency matrix, how can I make Mathematica draw exactly one self loop for any non-zero weight?

I have tried using the option MultiedgeStyle->None, but apparently Mathematica doesn't treat self loops in the same way it treats edges. For example, I find ...
644 views

### Most efficient way to obtain samples from high-dimensional multivariate distributions?

Is MultinormalDistribution[] efficient and easy to use for high dimensions? I have a variable $n$ representing the dimension of a Monte Carlo integration I do on a ...
385 views

### Defining a ForEach function

Consider the following function definition: ForEach[iterators__] := Table[#, iterators] &; Two questions about it: I. It works perfectly if you call it like ...
442 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 ...