A statistical test for Nested Sampling algorithms
Nested sampling is an iterative integration procedure that shrinks the prior volume towards higher likelihoods by removing a “live” point at a time. A replacement point is drawn uniformly from the prior above an ever-increasing likelihood threshold. Thus, the problem of drawing from a space above a...
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| Published in: | Statistics and computing Vol. 26; no. 1-2; pp. 383 - 392 |
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| Main Author: | |
| Format: | Journal Article |
| Language: | English |
| Published: |
New York
Springer US
01.01.2016
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| Subjects: | |
| ISSN: | 0960-3174, 1573-1375 |
| Online Access: | Get full text |
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| Summary: | Nested sampling is an iterative integration procedure that shrinks the prior volume towards higher likelihoods by removing a “live” point at a time. A replacement point is drawn uniformly from the prior above an ever-increasing likelihood threshold. Thus, the problem of drawing from a space above a certain likelihood value arises naturally in nested sampling, making algorithms that solve this problem a key ingredient to the nested sampling framework. If the drawn points are distributed uniformly, the removal of a point shrinks the volume in a well-understood way, and the integration of nested sampling is unbiased. In this work, I develop a statistical test to check whether this is the case. This “Shrinkage Test” is useful to verify nested sampling algorithms in a controlled environment. I apply the shrinkage test to a test-problem, and show that some existing algorithms fail to pass it due to over-optimisation. I then demonstrate that a simple algorithm can be constructed which is robust against this type of problem. This RADFRIENDS algorithm is, however, inefficient in comparison to MULTINEST. |
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| ISSN: | 0960-3174 1573-1375 |
| DOI: | 10.1007/s11222-014-9512-y |