Comments on: Dilation algorithms—Introduction

By: software developer

software developer — Fri, 16 Oct 2009 09:24:06 +0000

Interesting,

this is a good article to help with algorithms…

keep up the good work

Thanks for writing about it

By: Steve

Steve — Thu, 04 Sep 2008 17:40:32 +0000

Cris—You’re right, I should have caught the plot scaling issue. I wasn’t actually trying hide the point. I updated the post to make it more clear. Thanks. Also, thanks for the TrIP pointer; I’ll take a look.

By: Cris Luengo

Cris Luengo — Thu, 04 Sep 2008 15:04:15 +0000

Not to spoil your upcoming bog entry too much, but if you scale the first graph (times vs Q) by setting the lower ylim to 0, you’ll see it is pretty close to a horizontal line. There’s only a 10% difference from low to high.

However, isn’t this supposed to be an O(1) algorithm? Where’s the increase coming from? Actually, only yesterday I saw some paper with a timing plot, where operations with a linear SE actually had lower times for longer SE. That one seriously surprises to me! (Urbach and Wilkinson, IEEE TIP 17(1):1-8, fig 9)

By: Steve

Steve — Thu, 04 Sep 2008 01:58:37 +0000

Jim—Thanks for adding your comment showing how the syntax works for matrices.

By: Jim

Jim — Wed, 03 Sep 2008 21:33:30 +0000

for i = A
…statements…
end;

Description:
The …statements… are executed (as MATLAB commands) for i equal sequentially to each column in A. If A is 3D or greater, the …statements… are executed for i equal sequentially to the vector of first index values for each combination of the other indices of A.

Example:
A = [1 2 3; 4 5 6];
for i = A
this_is_i = i
end;

Result:
this_is_i =

1.00
4.00

this_is_i =

2.00
5.00

this_is_i =

3.00
6.00

By: Steve

Steve — Wed, 03 Sep 2008 20:51:14 +0000

Omar—Nice work.

By: Omar

Omar — Wed, 03 Sep 2008 20:38:51 +0000

for wk = w

w is a 1-by-n vector that contains n indices. wk will iterate n-times w and use each value in w as a current index. E.g.,

wk = [1, 3, 5, 7]

wk will have values (1,3,5,7) at each of the four iterations.