1,115 research outputs found
Hamevol1.0: a C++ code for differential equations based on Runge-Kutta algorithm. An application to matter enhanced neutrino oscillation
We present a C++ implementation of a fifth order semi-implicit Runge-Kutta
algorithm for solving Ordinary Differential Equations. This algorithm can be
used for studying many different problems and in particular it can be applied
for computing the evolution of any system whose Hamiltonian is known. We
consider in particular the problem of calculating the neutrino oscillation
probabilities in presence of matter interactions. The time performance and the
accuracy of this implementation is competitive with respect to the other
analytical and numerical techniques used in literature. The algorithm design
and the salient features of the code are presented and discussed and some
explicit examples of code application are given.Comment: 18 pages, Late
The Road to Quantum Computational Supremacy
We present an idiosyncratic view of the race for quantum computational
supremacy. Google's approach and IBM challenge are examined. An unexpected
side-effect of the race is the significant progress in designing fast classical
algorithms. Quantum supremacy, if achieved, won't make classical computing
obsolete.Comment: 15 pages, 1 figur
Adaptive cuckoo filters
We introduce the adaptive cuckoo filter (ACF), a data structure for approximate set membership that extends
cuckoo filters by reacting to false positives, removing them for future queries. As an example application,
in packet processing queries may correspond to flow identifiers, so a search for an element is likely to be
followed by repeated searches for that element. Removing false positives can therefore significantly lower
the false-positive rate. The ACF, like the cuckoo filter, uses a cuckoo hash table to store fingerprints. We allow
fingerprint entries to be changed in response to a false positive in a manner designed to minimize the effect
on the performance of the filter. We show that the ACF is able to significantly reduce the false-positive rate
by presenting both a theoretical model for the false-positive rate and simulations using both synthetic data
sets and real packet trace
Fully Dynamic Single-Source Reachability in Practice: An Experimental Study
Given a directed graph and a source vertex, the fully dynamic single-source
reachability problem is to maintain the set of vertices that are reachable from
the given vertex, subject to edge deletions and insertions. It is one of the
most fundamental problems on graphs and appears directly or indirectly in many
and varied applications. While there has been theoretical work on this problem,
showing both linear conditional lower bounds for the fully dynamic problem and
insertions-only and deletions-only upper bounds beating these conditional lower
bounds, there has been no experimental study that compares the performance of
fully dynamic reachability algorithms in practice. Previous experimental
studies in this area concentrated only on the more general all-pairs
reachability or transitive closure problem and did not use real-world dynamic
graphs.
In this paper, we bridge this gap by empirically studying an extensive set of
algorithms for the single-source reachability problem in the fully dynamic
setting. In particular, we design several fully dynamic variants of well-known
approaches to obtain and maintain reachability information with respect to a
distinguished source. Moreover, we extend the existing insertions-only or
deletions-only upper bounds into fully dynamic algorithms. Even though the
worst-case time per operation of all the fully dynamic algorithms we evaluate
is at least linear in the number of edges in the graph (as is to be expected
given the conditional lower bounds) we show in our extensive experimental
evaluation that their performance differs greatly, both on generated as well as
on real-world instances
Dagstuhl News January - December 2002
"Dagstuhl News" is a publication edited especially for the members of the Foundation "Informatikzentrum Schloss Dagstuhl" to thank them for their support. The News give a summary of the scientific work being done in Dagstuhl. Each Dagstuhl Seminar is presented by a small abstract describing the contents and scientific highlights of the seminar as well as the perspectives or challenges of the research topic
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