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How to program efficient pattern searches in a list of float numbers?

Charles Krug cdkrug at worldnet.att.net
Mon Sep 19 09:06:29 EDT 2005 
On 19 Sep 2005 00:02:34 -0700, malv <malvert at telenet.be> wrote:
> Simple case:
> In this list, how to find all occurences of intervals of n adjacent
> indexes having at least one list-member with a value between given
> limits.
> Visualizing the list as a two-dimensional curve, this is like
> horizontally dragging a given rectangle over the curve and finding the
> x coordinates where the curve passes through the rectangle.(Define such
> a x-index coordinate as the left corner of the rectangle.)
> 
> More complicated case:
> Given a pair of rectangles spaced relatively to each other in a fixed
> manner. Drag this rectangle pair horizontally over the above
> two-dimensional curve and list the indexes of the occurences where the
> curve passes simultaneously through both rectangles.
> (Define such a x-index coordinate as the leftmost corner of the
> rectangle pair).
> 
> These problems can be solved by programming a naive search advancing
> index by index. It seems obvious that due to the localized properties
> searched for, much more efficient searches should be possible.
> After having found the occurence-indexes for one particular rectangle
> set, how to find the pattern occurences after changing one or more
> rectangle parameters?
> 

Make a picture of the problem.  From your description, I'm not certain
anything more complicated than a linear search is called for.

Is this the phrasing of the original problem presentation?  Seems to me
the word "superimpose" ought to occur here.

Another thought:  What is the end result you're after?  Often we start
thinking of a solution but lose sight of the end result.  Then another
solution will pop into our mind that makes it Oh So Simple.
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