Alan H. Karp

Learn More
Explicit Runge-Kutta methods (RKMs) are among the most popular classes of formulas for the approximate numerical integration of nonstiff, initial value problems. However, high-order Runge-Kutta methods require more function evaluations per integration step than, for example, Adams methods used in PECE mode, and so, with RKMs, it is expecially important to(More)
The state of the art of parallel programming and what a sorry state that art is in. In the last few years we have seen an explosion in the interest in and availability of parallel processors' and a corresponding expansion in applications programming activity. Clearly, applications programmers need tools to express the parallelism, either in the form of(More)
We present division and square root algorithm for calculations with more bits than are handled by the floating-point hardware. These algorithms avoid the need to multiply two high-precision numbers, speeding up the last iteration by as much as a factor of 10. We also show how to produce the floating-point number closest to the exact result with relatively(More)
Bit reversal, hierarchical memory, Fast Fourier Transform Many versions of the Fast Fourier Transform require a reordering of either the input or the output data that corresponds to reversing the order of the bits in the array index. There has been a surprisingly large number of papers on this subject in the recent literature. This paper collects 30 methods(More)
RDF(Resource Description Framework), graph, digest, signature, cryptography, security Efficient algorithms are needed for computing the digest of a Resource Description Framework (RDF) graph. These may be used to assign unique content-dependent identifiers and for use in digital signatures, allowing a recipient to verify that RDF was generated by a(More)
  • Alan H. Karp
  • Fourth International Conference on Creating…
  • 2006
Several attempts at using the services oriented architecture have failed to achieve their goals of scalability, security, and manageability. These systems, which base access decisions on the identity of the requester, have been found to be inflexible, don't scale well, and are difficult to use and to upgrade. This paper shows that identity-based access(More)
The most time consuming part of an N-body simulation is computing the components of the accelerations of the particles. On most machines the slowest part of computing the acceleration is in evaluating r 3=2 which is especially true on machines that do the square root in software. This note shows how to cut the time for this part of the calculation by a(More)