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We establish optimal error bounds for the exponential wave integrator (EWI) applied to the nonlinear Schr\"odinger equation (NLSE) with $ L^\infty $-potential and/or locally Lipschitz nonlinearity under the assumption of $ H^2 $-solution of…

Numerical Analysis · Mathematics 2024-01-15 Weizhu Bao , Chushan Wang

Recently, it was observed that solutions of a large class of highly oscillatory second order linear ordinary differential equations can be approximated using nonoscillatory phase functions. In particular, under mild assumptions on the…

Classical Analysis and ODEs · Mathematics 2015-05-22 James Bremer , Vladimir Rokhlin

In our recent publication [1] we presented an exponential series approximation suitable for highly accurate computation of the complex error function in a rapid algorithm. In this Short Communication we describe how a simplified…

Numerical Analysis · Mathematics 2012-05-09 S. M. Abrarov , B. M. Quine

We derive the equations to calculate the reduced width amplitudes (RWA) of the different size clusters and deformed clusters without any approximation. These equations named Laplace expansion method are applicable to the nuclear models…

Nuclear Theory · Physics 2017-03-16 Yohei Chiba , Masaaki Kimura

The double exponential formula was introduced for calculating definite integrals with singular point oscillation functions and Fourier integral. The double exponential transformation is not only useful for numerical computations but it is…

General Mathematics · Mathematics 2017-04-20 Arezoo Khatibi , Omid Khatibi

Agarwal et al. gave an closed-form expression for write amplification in NAND flash memory by finding the probability of a page being valid over the whole flash memory. This paper gives an improved analytic expression for write…

Performance · Computer Science 2011-10-20 Luojie Xiang , Brian Kurkoski

We improve the Modified Winitzki's Approximation of the error function $erf(x)\cong \sqrt{1-e^{-x^2\frac{\frac{4}{\pi}+0.147x^2}{1+0.147x^2}}}$ which has error $|\varepsilon (x)| < 1.25 \cdot 10^{-4}$ $\forall x \ge 0$ till reaching 4…

Computation · Statistics 2012-01-09 A. Soranzo , E. Epure

Linear second order differential equations of the form $d^{2}w/dz^{2}-\left \{ {u^{2}f\left( u,z\right) +g\left( z\right) }\right\} w=0$ are studied, where $\left| u\right| \rightarrow \infty $ and $z$ lies in a complex bounded or unbounded…

Classical Analysis and ODEs · Mathematics 2017-08-03 T. M. Dunster

Extended full-waveform inversion (FWI) has shown promising results for accurate estimation of subsurface parameters when the initial models are not sufficiently accurate. Frequency-domain applications have shown that the augmented…

Numerical Analysis · Mathematics 2021-09-16 Ali Gholami , Hossein S. Aghamiry , Stephane Operto

In this paper we show that a methodology based on a sampling with the Gaussian function of kind $h\,{e^{ - {{\left( {t/c} \right)}^2}}}/\left( {{c}\sqrt \pi } \right)$, where ${c}$ and $h$ are some constants, leads to the Fourier transform…

General Mathematics · Mathematics 2015-08-06 S. M. Abrarov , B. M. Quine

In non-stationary signal processing, prior work has incorporated the quadratic-phase Fourier transform (QPFT) into the ambiguity function (AF) and Wigner distribution (WD) to enhance their performance. This paper introduces an advanced…

Functional Analysis · Mathematics 2025-03-21 Aamir H. Dar , Neeraj Kumar Sharma

In statistical mechanics, evaluating finite-size macroscopic fluctuations typically relies on Edgeworth expansions. However, these perturbative methods append additive polynomial corrections that inevitably break down in the large deviation…

Information Theory · Computer Science 2026-04-15 Hiroki Suyari

The availability of low frequency data is an important factor in the success of full waveform inversion (FWI) in the acoustic regime. The low frequencies help determine the kinematically relevant, low-wavenumber components of the velocity…

Geophysics · Physics 2016-01-21 Yunyue Elita Li , Laurent Demanet

The Burrows-Wheeler transform (BWT) is a reversible transform that converts a string $w$ into another string $\mathsf{BWT}(w)$. The size of the run-length encoded BWT (RLBWT) can be interpreted as a measure of repetitiveness in the class of…

Discrete Mathematics · Computer Science 2024-11-19 Hideo Bannai , Tomohiro I , Yuto Nakashima

In this paper, we consider a method for fast numerical computation of the Fourier transform of a slowly decaying function with given accuracy in given ranges of the frequency. In these decades, some useful formulas for the Fourier transform…

Numerical Analysis · Mathematics 2015-07-28 Ken'ichiro Tanaka

The full width at half maximum (FWHM) is a useful quantity for characterizing the bandwidth of unimodal functions. However, a closed-form expression for the FWHM of gamma-shaped functions-i.e. functions that are shaped like the gamma…

Signal Processing · Electrical Eng. & Systems 2025-09-25 Anthony LoPrete , Johannes Burge

Fluid antenna systems (FAS) achieve spatial diversity by dynamically switching among $N$ densely packed ports, but the resulting spatially correlated Rayleigh channels render exact outage analysis intractable. Existing block-correlation…

Signal Processing · Electrical Eng. & Systems 2026-03-24 Tuo Wu

Full-waveform inversion (FWI) with extended sources first computes wavefields with data-driven source extensions, such that the simulated data in inaccurate velocity models match the observed counterpart well enough to prevent cycle…

Geophysics · Physics 2023-03-03 Gaoshan Guo , Stephane Operto , Ali Gholami , Hossein S. Aghamiry

The reported results for ultrasonic wave attenuation constant ({\alpha}) in pure water show noticeable inconsistency in magnitude. A "Propagating-Wave" model analysis of the most popular pulse-echo technique indicates that this is a…

Other Condensed Matter · Physics 2018-01-18 Barnana Pal

Full-waveform inversion is a cutting-edge methodology for recovering high-resolution subsurface models. However, one of the main conventional full-waveform optimization problems challenges is cycle-skipping, usually leading us to an…

Computational Physics · Physics 2022-05-20 Muhammad Izzatullah , Tariq Alkhalifah