J. Demmel, 1995. private communication.  Home/Search   Document Not in Database   Summary   Related Articles   Check

....version of BIND that would log just those queries. This version identified the next host back in the query chain, from which we identify several problem end user applications. To date, we have determined three causes of the bogus A queries, all on Windows systems: the Win2k resolver library [6], the snow white virus, also called W32.HybrisF [7] that infects the Winsock dynamically linked library and the wininit virus, called W32.HLLW.Bymer [8] that trolls for disk shares to infect via port 137. The OpenBSD resolver and some DSL modem boxes seem to be guilty too. The extremely high ....

James Gilroy, private communication.

....k ) the Newton iteration is well defined and converges quadratically to zero. The residual F (bv i ) can be computed in mixed precision by the XBLAS routine GE SUM MV. If only an extra precision gaxpy operation is available then the computation can be done less efficiently as follows [4]: Compute a 1 = f l u (f l u (Abx) Compute a 2 = f l u (f l u (Abx Gamma a 1 ) Now (a 1 ; a 2 ) is the double double representation of Ax. Bbx) b Bbx Gamma b 1 ) r(i) f l u (f l u (a 1 (i) a 2 (i) b 1 (i) b 2 (i) i = 1: n. For either case, we can take (F; v; ....

James W. Demmel. Private communication. 1999.

....LALR(1) or LL(1) is familiar with the difficulties. 4 (ii) Our next example shows that actions do occur naturally in the middle of rules some actions cannot be moved to the right edges of a production. Again, our example uses an action to update the symbol table for lexer. In Jim Roskind s [13] precisely tuned YACC C grammar, his comments indicate that parsing scoped names of the form xxx: yyy require the lexer to look up the name yyy in the namespace for xxx. In C , the notation xxx: yyy refers to name yyy in scope xxx where the scope is assumed to be global if xxx is absent. Thus ....

....specifying a grammar for the YACC language which describes the input to YACC itself. Surprisingly, the most natural grammar is LR(2) not LR(1) because the semicolon at the end of a YACC rule is optional, which implies that YACC cannot easily recognize its own input language. Jim Roskind [13], who pointed out this fact to us, also provided the following example YACC input. The problem arises when parsing Delta Delta Delta t t : Delta Delta Delta . s : A s A t t : B t B Two symbols of lookahead are required to determine when a rule ends. The difficulty is that we ....

James Roskind. Private communications, September 1994. 10

....of the ; the lexer would not return the correct token type. ii) Our next example shows that actions do occur naturally in the middle of rules 4 some actions cannot be moved to production right edges. As before, we need an action to update the symbol table for the lexer. In Jim Roskind s [Ros94] precisely tuned YACC C grammar, his comments indicate that parsing scoped names of the form xxx: yyy 1 require the lexer to look up the name yyy in a context dependent manner. The following is the rule from Roskind s grammar that handles this situation for global scope overrides. global scope: ....

....2: Consider specifying a grammar for the YACC language which is the input to YACC itself. Surprisingly, the most natural grammar is LR(2) not LR(1) because the semicolons on the end of rules are optional. This implies that YACC cannot easily recognize its own input language. Jim Roskind [Ros94], who pointed out this fact, also provided the following example YACC input: s : A s A t t : B t B Two symbols of lookahead are required to determine when a rule has ended. The difficulty lies in that you have to scan past a token to check for a following : to determine whether or ....

James Roskind. Private communications, September 1994.

....closed loop water in the de ionization process. The following is an estimate of the tritium build up in the hadronic hose cooling water. A MARS Monte Carlo calculation yields an average hadronic flux in the decay pipe steel of 2. 73 Theta10 Gamma6 hadrons cm Gamma2 proton on target Gamma1 [6]. At the NuMI design goal of 4 Theta10 13 protons per pulse, with one pulse every 1.9 s, the average hadronic flux in the decay pipe is then Phi = 5:75 Theta 10 6 hadrons cm Gamma2 s Gamma1 . For the purposes of this estimate, the hadronic flux through the water is assumed to be the ....

C. James, private communication, March 2000.

....data at the lowest energies ( 20 GeV) where the flux is highest. The apparent rational for this parameterization s continued use is that this disagreement is irrelevant for the typical cases where it is used: underground experiments. The minos near detector hall is to be located 340 feet (103.6m)[4] below the surface. Taking SiO 2 to be a reasonable approximation to the rock overburden, the energy loss is 1.72 [MeV (g cm 2 ) and the density is ae = 2:63 [g cm 3 ] 4] This results in a minimum loss of 46 GeV. Thus for such experiments the spectrum below this threshold is irrelevant. ....

....typical cases where it is used: underground experiments. The minos near detector hall is to be located 340 feet (103.6m) 4] below the surface. Taking SiO 2 to be a reasonable approximation to the rock overburden, the energy loss is 1. 72 [MeV (g cm 2 ) and the density is ae = 2:63 [g cm 3 ][4]. This results in a minimum loss of 46 GeV. Thus for such experiments the spectrum below this threshold is irrelevant. On the other hand, for the simulation of surface experiments it is important to get this right. Distortions induced by this mischaracterization push the average muon energy down ....

C. James, private communication.

....as an integer between GammaH and H , it is known exactly. To compute the determinant modulo P , it is computed modulo each p i (typically using Gaussian elimination) and reconstructed from these residues. Before running the Chinese remainder code, we use a new filter based proposed by Demmel [Dem98] The integer matrix is approximated with a double precision floating point matrix, and its singular value decomposition (SVD) is computed using the LAPACK library [ABB 92] The determinant sign is easily read off from the SVD. To diagnose the correctness of this sign, we apply a backwards ....

J. Demmel. Private Communication, 1998.

....is insensitive to the size of the problem. Rather than working on an entire row or column of a matrix, such blocked algorithms rearrange computations to work on submatrices or blocks that will fit in a cache [45, 77] Such rearrangements are designed not to affect the vectorizability of a program [29]. Hence, if a blocked algorithm performs 1 I use the words program and algorithm interchangeably. 37 well on a superscalar architecture, it should also perform well on a vector architecture. Although memory implementation and memory demand are independent of the processor architecture, a ....

James Demmel. Private communication, 28 January 1992.

No context found.

James Hylen (private communication, Nov. 21, 1996)

No context found.

J. Demmel, 1995. private communication.

No context found.

James Sybert. Private Communication.

No context found.

F. James, private communication.

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