Convergent compilation applied to loop unrolling

Abstract. Well-engineered compilers use a carefully selected set of optimizations, heuristic optimization policies, and a phase ordering. Designing a single optimization heuristic that works well with other optimization phases is a challenging task. Although compiler designers evaluate heuristics and phase orderings before deployment, compilers typically do not statically evaluate nor refine the quality of their optimization decisions during a specific compilation. This paper identifies a class of optimizations for which the compiler can statically evaluate the effectiveness of its heuristics and phase interactions. When necessary, it then modifies and reapplies its optimization policies. We call this approach convergent compilation, since it iterates to converge on high quality code. This model incurs additional compilation time to avoid some of the difficulties of predicting phase interactions and perfecting heuristics This work was motivated by the TRIPS architecture which has resourc

A global biogeographic classification of the mesopelagic zone

We have developed a global biogeographic classification of the mesopelagic zone to reflect the regional scales over which the ocean interior varies in terms of biodiversity and function. An integrated approach was necessary, as global gaps in information and variable sampling methods preclude strictly statistical approaches. A panel combining expertise in oceanography, geospatial mapping, and deep-sea biology convened to collate expert opinion on the distributional patterns of pelagic fauna relative to environmental proxies (temperature, salinity, and dissolved oxygen at mesopelagic depths). An iterative Delphi Method integrating additional biological and physical data was used to classify biogeographic ecoregions and to identify the location of ecoregion boundaries or inter-regions gradients. We define 33 global mesopelagic ecoregions. Of these, 20 are oceanic while 13 are ‘distant neritic.’ While each is driven by a complex of controlling factors, the putative primary driver of each ecoregion was identified. While work remains to be done to produce a comprehensive and robust mesopelagic biogeography (i.e., reflecting temporal variation), we believe that the classification set forth in this study will prove to be a useful and timely input to policy planning and management for conservation of deep-pelagic marine resources. In particular, it gives an indication of the spatial scale at which faunal communities are expected to be broadly similar in composition, and hence can inform application of ecosystem-based management approaches, marine spatial planning and the distribution and spacing of networks of representative protected areas

A global biogeographic classification of the mesopelagic zone

http://www.godac.jamstec.go.jp/darwin/cruise/kaiyo/ky02-06/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt00-08/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr07-14/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr04-12/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr04-07/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kaiyo/ky04-04/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt00-10/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt00-11/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt03-09_leg2/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kaiyo/ky99-06/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt00-06/ehttp://www.godac.jamstec.go.jp/darwin/cruise/yokosuka/yk00-04_leg2/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr98-07_leg2/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr99-03/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr98-09/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt97-10/ehttp://www.godac.jamstec.go.jp/darwin/cruise/kairei/kr97-05_leg3/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt13-09/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt06-03/

Guaranteed Optimization for Domain-Specific Programming

Abstract. For software engineering reasons, it is often best to provide domain-specific programming environments in the context of a generalpurpose language. In our view general-purpose languages are not yet general-purpose enough, and progress needs to be made before we can provide domain-specific languages that are both fast and safe. We outline some goals in this regard, and describe a possible implementation technology: guaranteed optimization, a technique for building compilers that provide proven guarantees of what optimizations they perform. Such optimizers can provide capabilities similar to staged languages, and thus provide the relevant performance improvements. They can also function as decision procedures, suggesting an approach of ’optimizers as theorem provers, ’ in which optimizing compilers can be used to check domainspecific safety properties and check proofs embedded in programs.