I like his slow, clear, methodical presentation with great visualizations. It is the first time I have deeply understood some of the volume visualization techniques we have.

• 1 of 9 Definitions for scalar and vector fields.
• 2 of 9 Examples of scalar and vector fields (temperature in a room vs air currents)
• 3 of 9 Displays scatter3 and slice plots.
• 4 of 9 Displays contourslice and isosurface.
• 5 of 9 Making a 3-d plot ‘pretty’ with lighting, shading, interpolation, etc…
• 6 of 9 Displays quiver3 and coneplot

I like his slow, clear, methodical presentation with great visualizations. It is the first time I have deeply understood some of the volume visualization techniques we have.

• 1 of 9 Definitions for scalar and vector fields.
• 2 of 9 Examples of scalar and vector fields (temperature in a room vs air currents)
• 3 of 9 Displays scatter3 and slice plots.
• 4 of 9 Displays contourslice and isosurface.
• 5 of 9 Making a 3-d plot ‘pretty’ with lighting, shading, interpolation, etc…

However, we can see that on some of the boards, the winning entry did significantly better. The boards that it won on were those with the large valued 80’s randomly around the board.

Surprising to me, the 1000 node solver did noticably better on a couple of the tall skinny boards like this:

That leaves me wondering if someone could have done a quick check to see if the board had 30 colors or so, and then tried the simpler solver. It looks like this would have made some significant gains… A good contest, congratulations to all that participated.]]> http://blogs.mathworks.com/videos/2009/11/13/contest-flood-wrap-up/feed/ http://blogs.mathworks.com/videos/2009/11/13/contest-flood-wrap-up/ http://feedproxy.google.com/~r/DougsMatlabVideoTutorials/~3/4LF6JFJmRPE/ http://blogs.mathworks.com/videos/2009/11/11/basics-volume-visualization-49-display-of-contourslice-and-isosurface/#comments Wed, 11 Nov 2009 14:55:37 +0000 dhull http://blogs.mathworks.com/videos/2009/11/11/basics-volume-visualization-49-display-of-contourslice-and-isosurface/

I like his slow, clear, methodical presentation with great visualizations. It is the first time I have deeply understood some of the volume visualization techniques we have.

• 1 of 9 Definitions for scalar and vector fields.
• 2 of 9 Examples of scalar and vector fields (temperature in a room vs air currents)
• 3 of 9 Displays scatter3 and slice plots.
• 4 of 9 Displays contourslice and isosurface.

I like his slow, clear, methodical presentation with great visualizations. It is the first time I have deeply understood some of the volume visualization techniques we have.

• 1 of 9 Definitions for scalar and vector fields.
• 2 of 9 Examples of scalar and vector fields (temperature in a room vs air currents)
• 3 of 9 Displays scatter3 and slice plots.

Get all the information here.

Our more faithful blog readers might have a head start on this puzzle…

Finding four connected regions.

A puzzler about the game that inspired this contest.

Winning entries to the above puzzler.]]> http://blogs.mathworks.com/videos/2009/11/04/contest-flooding/feed/ http://blogs.mathworks.com/videos/2009/11/04/contest-flooding/ http://feedproxy.google.com/~r/DougsMatlabVideoTutorials/~3/wkePmJPUsxE/ http://blogs.mathworks.com/videos/2009/11/03/puzzler-ultimate-frisbee-call-it-wrap-up/#comments Tue, 03 Nov 2009 14:49:03 +0000 dhull http://blogs.mathworks.com/videos/2009/11/03/puzzler-ultimate-frisbee-call-it-wrap-up/ “For two coins (i.e. Frisbees®) that have the same probability of being heads or tails (but not necessarily fair coins) you are at worst going to win 50% of the time when you choose ’same’.” (Here is the original post)

My argument on the Ultimate Frisbee field was

“Imagine the two Frisbee come up heads 99% of the time, what do you choose?”

“Same!”

“What about 98%?”

“Same”

“This logic holds all the way through, even to 50.00001. At 50% it just does not matter, so always choose same.”

The more rigorous and MATLAB proofs were more along these lines:

This was a GUI that you watched as it went through a Monte Carlo simulation. Thanks Richard

Arman did a more traditional proof, citing Wikipedia

Let p be the probability of having tails.
The probability of having "different" is p(1-p)+(1-p)p.
The probability of having "same" is p^2+(1-p)^2.

From the arithmetic mean geometric mean inequality, we know that

p^2+(1-p)^2 >= 2*p(1-p) and equality holds if p=1-p which means p=1/2.

Therefore “same” is better choice for any p value.

There were many variations on this plot:

I liked Zane’s here because it shows how much better off you are with ’same’ for each value of unfairness in the coin.

Christopher won the challenge by going to the next level, pointing out that you could make these unfair Frisbees almost fair by flipping three and calling for an odd number (1 or 3) vs even number (0 or 2) of heads.

Thank you everyone for playing, and finally putting this question to rest! Now the ethical question, knowing the coin flip is unfair, is it in the Spirit of The Game to let the other guy choose? Should we move to Christopher’s method of flipping three Frisbees?

Frisbee® is a Registered Trademark of © 2004 Wham-o Inc. All Rights Reserved. ]]> http://blogs.mathworks.com/videos/2009/11/03/puzzler-ultimate-frisbee-call-it-wrap-up/feed/ http://blogs.mathworks.com/videos/2009/11/03/puzzler-ultimate-frisbee-call-it-wrap-up/ http://feedproxy.google.com/~r/DougsMatlabVideoTutorials/~3/3cfrO9Tda2U/ http://blogs.mathworks.com/videos/2009/10/30/basics-volume-visualization-29-examples-of-scalar-and-vector-fields/#comments Fri, 30 Oct 2009 20:44:14 +0000 dhull http://blogs.mathworks.com/videos/2009/10/30/basics-volume-visualization-29-examples-of-scalar-and-vector-fields/

I like his slow, clear, methodical presentation with great visualizations. It is the first time I have deeply understood some of the volume visualization techniques we have.

• 1 of 9 Definitions for scalar and vector fields.
• 2 of 9 Examples of scalar and vector fields (temperature in a room vs air currents)

I made a convincing argument, but I am curious what kind of persuasive MATLAB-based ‘proofs’ can be made. I am offering a MATLAB t-shirt to the most persuasive entry. Use published MATLAB files, GUI’s, MATLAB script or function, whatever you think will be most convincing. Contest ends this time next week.

Assumptions: The Frisbees (or coins) are either ‘heads’ or ‘tails’. The coins may or may not be ‘fair’ (i.e. they might be heads 80% of the time!), however the odds of heads versus tails for the two coins is the same for both coins. Send entries to hull@MathWorks.com (no .rar files please!) (Here is the result of this now closed contest)

Frisbee® is a Registered Trademark of © 2004 Wham-o Inc. All Rights Reserved.]]> http://blogs.mathworks.com/videos/2009/10/27/puzzler-ultimate-frisbee-call-it/feed/ http://blogs.mathworks.com/videos/2009/10/27/puzzler-ultimate-frisbee-call-it/ http://feedproxy.google.com/~r/DougsMatlabVideoTutorials/~3/rzgYQc7D9oE/ http://blogs.mathworks.com/videos/2009/10/23/basics-volume-visualization-19-defining-scalar-and-vector-fields/#comments Fri, 23 Oct 2009 15:26:31 +0000 dhull http://blogs.mathworks.com/videos/2009/10/23/basics-volume-visualization-19-defining-scalar-and-vector-fields/

I like his slow, clear, methodical presentation with great visualizations. It is the first time I have deeply understood some of the volume visualization techniques we have. Sorry, Dr. H, but I really did not understand Div, Grad, Curl and all of that until Patrick explained it later in this series!

1 of 9 Definitions for scalar and vector fields.