5.9 Tuesday, November 1, 2016

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Top new questions this week: 
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[Huge bug involving MultinormalDistribution?] http://mathematica.stackexchange.com/questions/129916/huge-bug-involving-multinormaldistribution

Bug introduced in 8.0 or earlier and persisting through 11.0.1

I found a strange behavior regarding the CDF of the bivariate Normal distribution

...

- asked by fwgb (21 votes), answered by Eric Towers (19 votes)

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[GeoDistance - higher spatial resolution / precision?] http://mathematica.stackexchange.com/questions/130044/geodistance-higher-spatial-resolution-precision

I’m having a small problem with GeoDistance.

I’ve chosen a target city – San Francisco – and I’ve computed distances from SF to five other cities. Then I draw circles around each city, with radius ...

- asked by ConvexMartian (9 votes), answered by jose (4 votes)

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[How to extract the first dimension in TimeSeries?] http://mathematica.stackexchange.com/questions/129836/how-to-extract-the-first-dimension-in-timeseries

I want to extract the first dimension in TimeSeriesfor example:

So I use this code:

data = Normal@AudioLocalMeasurements[ExampleData[{"Audio", "PianoScale"}],"MFCC"]; 
Thread[{data[[All, 1]],  ...

- asked by partida (9 votes), answered by kglr (6 votes)

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[How to recover Pauli matrices properties in Mathematica?] http://mathematica.stackexchange.com/questions/129799/how-to-recover-pauli-matrices-properties-in-mathematica

I want to do a cross or dot product involving a vector of Pauli matrices =(1,2,3); for example, x=2i or .=3I.

Is there a simple way to do these operations?

- asked by user3654016 (8 votes), answered by corey979 (10 votes)

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[Flatten sublists within a bigger list] http://mathematica.stackexchange.com/questions/130011/flatten-sublists-within-a-bigger-list

Really sorry if this question is a duplicate. I couldn’t find exactly what I was looking for.

Here is a list I have:

{{{0. + 0.1875 I, 0. + 0.105469 I, 0. + 0.03125 I, 0. + 0.00390625 I, 
   0. +  ...

- asked by jrekier (7 votes), answered by Edmund (6 votes)

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[7-dimensional cross product] http://mathematica.stackexchange.com/questions/129863/7-dimensional-cross-product

How to define a 7-dimensional cross product?

$$\begin{aligned}\mathbf {x} \times \mathbf {y} =(x_{2}y_{4}-x_{4}y_{2}+x_{3}y_{7}-x_{7}y_{3}+x_{5}y_{6}-x_{6}y_{5})\,&\mathbf {e}  ...

- asked by corey979 (7 votes), answered by Sumit (4 votes)

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[How to draw a clock-diagram?] http://mathematica.stackexchange.com/questions/129960/how-to-draw-a-clock-diagram

I found a clock-diagram in a paper, so I would like to draw it in Mathematica. The main trouble for me is the corresponding line segments on the circle.

I would let the data1 lie the outside on the ...

- asked by user123 (7 votes), answered by Feyre (7 votes)

================================== Greatest hits from previous weeks: ==================================

[How can Mathematica be used to create images like these?] http://mathematica.stackexchange.com/questions/118992/how-can-mathematica-be-used-to-create-images-like-these

Here are two examples of artistic image interpolation using just black lines:

TRIANGULATION: ANGULAR CELEBRITIES DRAWN WITH A PEN Interpolation for Triangulation-represented Digital Image

The ...

- asked by R Hall (28 votes), answered by MarcoB (29 votes)

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[How to tell Mathematica that certain variables are real/imaginary, integer-valued, etc] http://mathematica.stackexchange.com/questions/66273/how-to-tell-mathematica-that-certain-variables-are-real-imaginary-integer-value

I’m trying to expedite some quantum mechanical calculations by running them through Mathematica. Expectation values and stuff like that. When I say, for example,

u[x_] := Sqrt[2/L] * Sin[Pi * n * x /  ...

- asked by Matthew Brunetti (8 votes), answered by SquareOne (6 votes)

================================== Can you answer these? ==================================

[How to Inset a legend in GeoGraphics with Scaled LegendMarkerSize?] http://mathematica.stackexchange.com/questions/130060/how-to-inset-a-legend-in-geographics-with-scaled-legendmarkersize

I have a GeoGraphics where I am using Scaled in PointSize to include size information. I want to Inset a PointLegend that describes the sizes of the points.

Outside of GeoGraphics I can do this by ...

- asked by Edmund (2 votes)

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[NumberLinePlot with Exponential] http://mathematica.stackexchange.com/questions/129938/numberlineplot-with-exponential

I have:

Clear[f, x] 
f[x_] = Exp[1/x] 
 
 
Now, the question is "where is the derivative negative?" I 
managed to get the Reduce command to work by adding Reals. 
 
Reduce[f'[x] < 0, x, Reals]

Which ...

- asked by David (3 votes)

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[Detect numbers on the image] http://mathematica.stackexchange.com/questions/129821/detect-numbers-on-the-image

How to detect numbers on the following image

I tried:

  img=Import["http://imgur.com/TDbn7sB.png"] 
 
  set = ImagePartition[img, Scaled[{1/20, 1/5}]] // Flatten

then I tried Classify[] but it ...

- asked by vito (3 votes)