On Fri, 13 Jul 2001 14:26:39 +0100, Tom Melly wrote:
>The whole business confuses me though - if eval "knows" what the true
>max_gradient should have been, why didn't it just use it in the first place?
>Okay, presumably it can only "know" the max_gradient after the event, but how?
>Without using a higher max_gradient, how can it know what value to predict?

It keeps track of the actual values as it subdivides the space, and if it 
finds a ray where two adjacent tests give values that would require a 
gradient above the current maximum, it assumes that the "real" maximum is at 
least as large as the observed value.  Of course, at that point it's too
late to retrace all the rays it's already done, so it just tells you about
it for next time.

Setting the starting maximum higher causes it to take more samples, which
in turn increases the chance that it will find any regions of even higher
gradient that might exist. 

-- 
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