Abstract
The “correct by construction” paradigm is an important component of modern Formal Methods, and here we use the probabilistic Guarded-Command Language pGCL to illustrate its application to probabilistic programming.
pGCL extends Dijkstra’s guarded-command language GCL with probabilistic choice, and is equipped with a correctness-preserving refinement relation (⊆) that enables compact, abstract specifications of probabilistic properties to be transformed gradually to concrete, executable code by applying mathematical insights in a systematic and layered way.
Characteristically for correctness by construction, as far as possible the reasoning in each refinement-step layer does not depend on earlier layers, and does not affect later ones.
We demonstrate the technique by deriving a fair-coin implementation of any given discrete probability distribution. In the special case of simulating a fair die, our correct-by-construction algorithm turns out to be “within spitting distance” of Knuth and Yao’s optimal solution.
| Original language | English |
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| Title of host publication | Leveraging Applications of Formal Methods, Verification and Validation |
| Subtitle of host publication | Verification Principles - 9th International Symposium on Leveraging Applications of Formal Methods, ISoLA 2020, Proceedings |
| Editors | Tiziana Margaria, Bernhard Steffen |
| Place of Publication | Cham, Switzerland |
| Publisher | Springer, Springer Nature |
| Pages | 216-239 |
| Number of pages | 24 |
| ISBN (Electronic) | 9783030613624 |
| ISBN (Print) | 9783030613617 |
| DOIs | |
| Publication status | Published - 2020 |
| Event | 9th International Symposium on Leveraging Applications of Formal Methods, Verification and Validation, ISoLA 2020 - Rhodes, Greece Duration: 20 Oct 2020 → 30 Oct 2020 |
Publication series
| Name | Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) |
|---|---|
| Volume | 12476 LNCS |
| ISSN (Print) | 0302-9743 |
| ISSN (Electronic) | 1611-3349 |
Conference
| Conference | 9th International Symposium on Leveraging Applications of Formal Methods, Verification and Validation, ISoLA 2020 |
|---|---|
| Country/Territory | Greece |
| City | Rhodes |
| Period | 20/10/20 → 30/10/20 |