13,039 research outputs found
A simple iterative algorithm for maxcut
We propose a simple iterative (SI) algorithm for the maxcut problem through
fully using an equivalent continuous formulation. It does not need rounding at
all and has advantages that all subproblems have explicit analytic solutions,
the cut values are monotonically updated and the iteration points converge to a
local optima in finite steps via an appropriate subgradient selection.
Numerical experiments on G-set demonstrate the performance. In particular, the
ratios between the best cut values achieved by SI and the best known ones are
at least and can be further improved to at least by a
preliminary attempt to break out of local optima.Comment: 30 pages, 1 figure. Subgradient selection, cost analysis and local
breakout are adde
Term and Quark Spin Content of the Nucleon
We report results of our calculation on the term and quark spin
content of the nucleon on the quenched lattice at . The disconnected insertions which involve contributions from the sea
quarks are calculated with the stochastic noise algorithm. As a physical
test of the algorithm, we show that the forward matrix elements of the vector
and pseudoscalar currents for the disconnected insertions are indeed consistent
with the known results of zero. We tried the Wuppertal smeared source and found
it to be more noisy than the point source. With unrenormalized
MeV, we find the term to be MeV. The
strange quark condensate in the nucleon is large, i.e. . For the quark spin content, we find
, , and . The flavor-singlet axial charge .Comment: contribution to Lattice '94; 3 page uuencoded ps fil
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