We consider unconstrained stochastic optimization problems with no available gradient information. Such arise in settings from derivative-free simulation to reinforcement learning. propose an adaptive sampling quasi-Newton method where we estimate the gradients using finite differences of function evaluations within a common random number framework. develop modified versions norm test and inner...

We analyze the equations of radiation hydrodynamics under the approximations of flux-limited diffusion and a thermal radiation field, and derive the minimal set of evolution equations that includes all terms that are of leading order in any regime of non-relativistic radiation hydrodynamics. Our equations are accurate to first order in v/c in the static diffusion regime. We give the equations i...

In this paper, we consider a zeroth-order perturbation q(x) of the buckling operator Δ2−κΔ, which can be uniquely determined by measuring Dirichlet-to-Neumann data on boundary. We extend conclusion biharmonic to operator, but map given in study is more meaningful and general.

Discretizations of Langevin diffusions provide a powerful method for sampling and Bayesian inference. However, such discretizations require evaluation the gradient potential function. In several real-world scenarios, obtaining evaluations might either be computationally expensive, or simply impossible. this work, we propose analyze stochastic zeroth-order algorithms discretizing overdamped unde...

The cancellation of the 0th order is described by a low-contrast fused-silica grating. In reported works, the high-contrast grating and complicated structure were applied with reasonable and excellent performance. However, the low-contrast grating is proved that it can also cancel the 0th order with the period more than 2λ in this paper. Grating parameters are optimized by using rigorous couple...

In ultrarelativistic heavy ion collisions a finite size QCD medium is created. In this paper we compute radiative energy loss to zeroth order in opacity by taking into account finite size effects. Transition radiation occurs on the boundary between the finite size medium and the vacuum, and we show that it lowers the difference between medium and vacuum zeroth order radiative energy loss relati...