John May

Dr. John May

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12 years, 75 days
Maplesoft
Guru
Pasadena, California, United States

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I am a Senior Developer in the Mathematical Software Group and have been with Maplesoft since 2007. I am also an Adjunct Assistant Professor in the School of Computer Science at the University of Waterloo.

I have a Ph.D in Mathematics from North Carolina State University as well as Masters and Bachelors degrees from the University of Oregon. I have been working on research in computational mathematics since 1997.

My main research interests in are computational linear and polynomial algebra, especially numerical polynomial algebra. I currently work on the exact algebraic solvers as well as other subsystems of Maple.

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These are replies submitted by John May

Or as a Vector constructor:

  v:= Vector(5, i->exp(i));

Or as a Vector constructor:

  v:= Vector(5, i->exp(i));

@gotamo You should be able to compute the variance using ?Statitics and ?ArrayTools in the following way.

(**) Statistics:-Variance( ArrayTools:-Reshape( img, 1..ArrayTools:-NumElems(img) ) );

Basically, ?Statistics:-Variance wants a one dimensional Array, and ?ArrayTools:-Reshape allows you to convert your two dimensional image into one. (In fact, it doesn't actually convert, it just provides an alias to the same piece of memory).

Hope that helps.

John

@gotamo You should be able to compute the variance using ?Statitics and ?ArrayTools in the following way.

(**) Statistics:-Variance( ArrayTools:-Reshape( img, 1..ArrayTools:-NumElems(img) ) );

Basically, ?Statistics:-Variance wants a one dimensional Array, and ?ArrayTools:-Reshape allows you to convert your two dimensional image into one. (In fact, it doesn't actually convert, it just provides an alias to the same piece of memory).

Hope that helps.

John

I don't work on the GUI team, and so I don't really have a horse in this race; I am just providing my honest advice on how to get the best Maple experience on a modern platform.

I don't work on the GUI team, and so I don't really have a horse in this race; I am just providing my honest advice on how to get the best Maple experience on a modern platform.

You'll need to include your system and the details of the problem in order for people to be able to help you.

One of the really cool parts of wordle is how it "packs" words around each other without overlapping.  The creator of wordle briefly describes how he did that at StackOverflow. The most difficult part of implementing that in Maple might be converting the words into polygons in order to detect collisions when creating the layout.

@acer Here is a (very slow) rule 30 based bit generator:

_30size := 232;
_30state := Vector(RandomTools:-Generate(list(integer(range=0..1), _30size)));

rand30 := proc()
local tmp0, tmp1, tmp2, i;
global _30state, _30size;
    tmp0 := _30state(1);
    tmp1 := _30state(_30size);
    for i from 1 to _30size-1 do
        tmp2 := _30state(i);
        _30state(i) := (tmp1 + tmp2*_30state(i + 1)) mod 2;
        tmp1 := tmp2;
    end do; 
    _30state(_30size) := tmp1 + _30state(_30size)*tmp0 mod 2;
    return _30state[floor(_30size/2)];
end proc;

I ran binary rank, Wald-Wolfowitz, and autocorrelation tests on it, and it does seem to be about as good as the PRNGs in Maple. (The first sequence of 10,000 bits generated did fail the 16x16 Binary rank test, but the next 10,000 passed)

@pagan To get images that are the size and quality that I want for my blog post, I am rendering them in Maple and then crop the formula I want from a screen shot.  I would love to be able to use MathML like the DLMF.

I just installed STIX on my workstation, and I have to say, MathML rendering in Firefox of the NIST DLMF is incredible good - in some cases better than their PNG images for non-mathml browsers (e.g. http://dlmf.nist.gov/7.7 ).

If you have a favourite professional American baseball team, and you don't want to download 100MB in baseball data to do the computation above.  Ask, and I can run them when I get a chance.

These are known as favicons.

John

While it may be more efficient for some simple cases, signum (which does its main work in `signum/main`) calls `is` to do its work.

While it may be more efficient for some simple cases, signum (which does its main work in `signum/main`) calls `is` to do its work.

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