An error in pbrt? About MLT start-up bias

Practical and theoretical implementation discussion.
shiqiu1105
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Joined: Sun May 27, 2012 4:42 pm

An error in pbrt? About MLT start-up bias

Postby shiqiu1105 » Fri Oct 03, 2014 8:45 am

Hi

I have been reading the MLT implementation in pbrt and trying to understand the math as much as I can.

One thing that confuses me is that, here in the start up phase, the initial sample X0 is sampled in the following way.
1.jpg
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where it says we need to weight all contributions with w.

However, when adding contribution, the w is ignored.. Is this a mistake?
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I derived it myself, and it seems like the w should equal to b. Should we multiply another b to all the contributions?

Also, Keleman's paper seems to be using a different weighting scheme for large step and rejection samples.
Compared the approach in pbrt, which one is better?

Thanks,

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