Shiva Kintali

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Betweenness is a centrality measure based on shortest paths, widely used in complex network analysis. It is computationally-expensive to exactly determine betweenness; currently the fastest-known algorithm by Brandes requires O(nm) time for unweighted graphs and O(nm + n log n) time for weighted graphs, where n is the number of vertices and m is the number(More)
Compiler technology for multimedia extensions must effectively utilize not only the SIMD compute engines but also the various levels of the memory hierarchy: superword registers, multi-level caches and TLB. In this paper, we describe a compiler that combines optimization across all levels of the memory hierarchy with automatic generation of SIMD code for(More)
  • Shiva Kintali
  • Electronic Colloquium on Computational Complexity
  • 2010
A celebrated theorem of Savitch [Sav70] states that NSPACE(S) ⊆ DSPACE(S). In particular, Savitch gave a deterministic algorithm to solve ST-CONNECTIVITY (an NL-complete problem) using O(logn) space, implying NL ⊆ DSPACE(logn). While Savitch’s theorem itself has not been improved in the last four decades, studying the space complexity of several special(More)
Scarf’s lemma is one of the fundamental results in combinatorics, originally introduced to study the core of an N -person game. Over the last four decades, the usefulness of Scarf’s lemma has been demonstrated in several important combinatorial problems. However, the complexity of the computational version of Scarf’s lemma (Scarf) is unknown. In this paper,(More)
One of the most fundamental problems in large scale network analysis is to determine the importance of a particular node in a network. Betweenness centrality is the most widely used metric to measure the importance of a node in a network. Currently the fastest known algorithm [5], to compute betweenness of all nodes, requires O(nm) time for unweighted(More)
In a landmark paper, Papadimitriou introduced a number of syntactic subclasses of TFNP based on proof styles that (unlike TFNP) admit complete problems. A recent series of results has shown that finding Nash equilibria is complete for PPAD, a particularly notable subclass of TFNP. A major goal of this work is to expand the universe of known PPAD-complete(More)
Consider the following problem. A seller has infinite copies of n products represented by nodes in a graph. There are m consumers, each has a budget and wants to buy two products. Consumers are represented by weighted edges. Given the prices of products, each consumer will buy both products she wants, at the given price, if she can afford to. Our objective(More)
The Border Gateway Protocol (BGP) is currently the only interdomain routing protocol deployed in the Internet. BGP can be viewed as a distributed algorithm for solving the Stable Paths Problem (SPP) [4]. Not every instance of SPP has a stable solution. The most general condition known to guarantee stability of SPP is the absence of dispute wheel, proposed(More)
Undirected graphs of pathwidth at most one are characterized by two forbidden minors i.e., (i) K3 the complete graph on three vertices and (ii) S2,2,2 the spider graph with three legs of length two each [BFKL87]. Directed pathwidth is a natural generalization of pathwidth to digraphs. In this paper, we prove that digraphs of directed pathwidth at most one(More)