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Fast SharedMemory Algorithms for Computing the Minimum Spanning Forest of Sparse Graphs
, 2006
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Accessing Multiple Sequences Through Set Associative Caches
 In Proc
, 1999
"... The cache hierarchy prevalent in todays high performance processors has to be taken into account in order to design algorithms which perform well in practice. We start from the empirical observation that external memory algorithms often turn out to be good algorithms for cached memory. This is n ..."
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Cited by 19 (4 self)
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The cache hierarchy prevalent in todays high performance processors has to be taken into account in order to design algorithms which perform well in practice. We start from the empirical observation that external memory algorithms often turn out to be good algorithms for cached memory. This is not self evident since caches have a fixed and quite restrictive algorithm choosing the content of the cache. We investigate the impact of this restriction for the frequently occurring case of access to multiple sequences. We show that any access pattern to k = \Theta(M=B ) sequential data streams can be efficiently supported on an away set associative cache with capacity M and line size B. The bounds are tight up to lower order terms.
A computational study of externalmemory BFS algorithms
 In SODA
, 2006
"... Breadth First Search (BFS) traversal is an archetype for many important graph problems. However, computing a BFS level decomposition for massive graphs was considered nonviable so far, because of the large number of I/Os it incurs. This paper presents the first experimental evaluation of recent exte ..."
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Cited by 18 (4 self)
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Breadth First Search (BFS) traversal is an archetype for many important graph problems. However, computing a BFS level decomposition for massive graphs was considered nonviable so far, because of the large number of I/Os it incurs. This paper presents the first experimental evaluation of recent externalmemory BFS algorithms for general graphs. With our STXXL based implementations exploiting pipelining and diskparallelism, we were able to compute the BFS level decomposition of a webcrawl based graph of around 130 million nodes and 1.4 billion edges in less than 4 hours using single disk and 2.3 hours using 4 disks. We demonstrate that some rather simple externalmemory algorithms perform significantly better (minutes as compared to hours) than internalmemory BFS, even if more than half of the input resides internally. 1
Engineering an External Memory Minimum Spanning Tree Algorithm
 IN PROC. 3RD IFIP INTL. CONF. ON THEORETICAL COMPUTER SCIENCE
, 2004
"... We develop an external memory algorithm for computing minimum spanning trees. The algorithm is considerably simpler than previously known external memory algorithms for this problem and needs a factor of at least four less I/Os for realistic inputs. Our implementation indicates that this algorithm ..."
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Cited by 14 (3 self)
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We develop an external memory algorithm for computing minimum spanning trees. The algorithm is considerably simpler than previously known external memory algorithms for this problem and needs a factor of at least four less I/Os for realistic inputs. Our implementation indicates that this algorithm processes graphs only limited by the disk capacity of most current machines in time no more than a factor 2–5 of a good internal algorithm with sufficient memory space.
Scanning Multiple Sequences Via Cache Memory
 Algorithmica
, 2003
"... We consider the simple problem of scanning multiple sequences. There are k sequences of total length N which are to be scanned concurrently. One pointer into each sequence is maintained and an adversary specifies which pointer is to be advanced. The concept of scanning multiple sequence is ubiquitou ..."
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Cited by 5 (0 self)
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We consider the simple problem of scanning multiple sequences. There are k sequences of total length N which are to be scanned concurrently. One pointer into each sequence is maintained and an adversary specifies which pointer is to be advanced. The concept of scanning multiple sequence is ubiquitous in algorithms designed for hierarchical memory.
An Empirical Analysis of Parallel Random Permutation Algorithms on
"... We compare parallel algorithms for random permutation generation on symmetric multiprocessors (SMPs). Algorithms considered are the sortingbased algorithm, Anderson’s shuffling algorithm, the dartthrowing algorithm, and Sanders ’ algorithm. We investigate the impact of synchronization method, memor ..."
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Cited by 1 (0 self)
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We compare parallel algorithms for random permutation generation on symmetric multiprocessors (SMPs). Algorithms considered are the sortingbased algorithm, Anderson’s shuffling algorithm, the dartthrowing algorithm, and Sanders ’ algorithm. We investigate the impact of synchronization method, memory access pattern, cost of generating random numbers and other parameters on the performance of the algorithms. Within the range of inputs used and processors employed, Anderson’s algorithm is preferable due to its simplicity when random number generation is relatively costly, while Sanders ’ algorithm has superior performance due to good cache performance when a fast random number generator is available. There is no definite winner across all settings. In fact we predict our new dartthrowing algorithm performs best when synchronization among processors becomes costly and memory access is relatively fast. We also compare the performance of our parallel implementations with the sequential implementation. It is unclear without extensive experimental studies whether fast parallel algorithms beat efficient sequential algorithms due to mismatch between model and architecture. Our implementations achieve speedups up to 6 with 12 processors on the Sun E4500.
A Synopsis of FormatPreserving Encryption
 UNPUBLISHED MANUSCRIPT
, 2010
"... Formatpreserving encryption (FPE) encrypts a plaintext of some specified format into a ciphertext of the same format—for example, encrypting a socialsecurity number into a socialsecurity number. In this survey we describe FPE and review known techniques for achieving it. These include FFX, a rece ..."
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Formatpreserving encryption (FPE) encrypts a plaintext of some specified format into a ciphertext of the same format—for example, encrypting a socialsecurity number into a socialsecurity number. In this survey we describe FPE and review known techniques for achieving it. These include FFX, a recent proposal made to NIST.