1,865 research outputs found
Dynamic Algorithms for the Massively Parallel Computation Model
The Massive Parallel Computing (MPC) model gained popularity during the last
decade and it is now seen as the standard model for processing large scale
data. One significant shortcoming of the model is that it assumes to work on
static datasets while, in practice, real-world datasets evolve continuously. To
overcome this issue, in this paper we initiate the study of dynamic algorithms
in the MPC model.
We first discuss the main requirements for a dynamic parallel model and we
show how to adapt the classic MPC model to capture them. Then we analyze the
connection between classic dynamic algorithms and dynamic algorithms in the MPC
model. Finally, we provide new efficient dynamic MPC algorithms for a variety
of fundamental graph problems, including connectivity, minimum spanning tree
and matching.Comment: Accepted to the 31st ACM Symposium on Parallelism in Algorithms and
Architectures (SPAA 2019
Global Alignment of Molecular Sequences via Ancestral State Reconstruction
Molecular phylogenetic techniques do not generally account for such common
evolutionary events as site insertions and deletions (known as indels). Instead
tree building algorithms and ancestral state inference procedures typically
rely on substitution-only models of sequence evolution. In practice these
methods are extended beyond this simplified setting with the use of heuristics
that produce global alignments of the input sequences--an important problem
which has no rigorous model-based solution. In this paper we consider a new
version of the multiple sequence alignment in the context of stochastic indel
models. More precisely, we introduce the following {\em trace reconstruction
problem on a tree} (TRPT): a binary sequence is broadcast through a tree
channel where we allow substitutions, deletions, and insertions; we seek to
reconstruct the original sequence from the sequences received at the leaves of
the tree. We give a recursive procedure for this problem with strong
reconstruction guarantees at low mutation rates, providing also an alignment of
the sequences at the leaves of the tree. The TRPT problem without indels has
been studied in previous work (Mossel 2004, Daskalakis et al. 2006) as a
bootstrapping step towards obtaining optimal phylogenetic reconstruction
methods. The present work sets up a framework for extending these works to
evolutionary models with indels
- …