Numerical analysis | Approximation theory
In mathematics, approximation theory is concerned with how functions can best be approximated with simpler functions, and with quantitatively characterizing the errors introduced thereby. Note that what is meant by best and simpler will depend on the application. A closely related topic is the approximation of functions by generalized Fourier series, that is, approximations based upon summation of a series of terms based upon orthogonal polynomials. One problem of particular interest is that of approximating a function in a computer mathematical library, using operations that can be performed on the computer or calculator (e.g. addition and multiplication), such that the result is as close to the actual function as possible. This is typically done with polynomial or rational (ratio of polynomials) approximations. The objective is to make the approximation as close as possible to the actual function, typically with an accuracy close to that of the underlying computer's floating point arithmetic. This is accomplished by using a polynomial of high degree, and/or narrowing the domain over which the polynomial has to approximate the function.Narrowing the domain can often be done through the use of various addition or scaling formulas for the function being approximated. Modern mathematical libraries often reduce the domain into many tiny segments and use a low-degree polynomial for each segment. (Wikipedia).
Approximating Functions in a Metric Space
Approximations are common in many areas of mathematics from Taylor series to machine learning. In this video, we will define what is meant by a best approximation and prove that a best approximation exists in a metric space. Chapters 0:00 - Examples of Approximation 0:46 - Best Aproximati
From playlist Approximation Theory
Polynomial approximations -- Calculus II
This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.
From playlist Calculus II
The Lp Norm for Vectors and Functions
In this video, we expand on the idea of L1 and L2 norms, introduced in the previous video to the more general Lp norm. We will get explain how the norms are calculated and try to get an intuition of the differences between the different Lp norms. Chapters 0:00 - Introduction 1:15 - Lp No
From playlist Approximation Theory
Minimax Approximation and the Exchange Algorithm
In this video we'll discuss minimax approximation. This is a method of approximating functions by minimisation of the infinity (uniform) norm. The exchange algorithm is an iterative method of finding the approximation which minimises the infinity norm. FAQ : How do you make these animatio
From playlist Approximation Theory
Accuracy of Taylor approximations - Calculus II
This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.
From playlist Calculus II
Error bounds for Taylor approximations -- Calculus II
This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.
From playlist Calculus II
Linear Approximations and Differentials
Linear Approximation In this video, I explain the concept of a linear approximation, which is just a way of approximating a function of several variables by its tangent planes, and I illustrate this by approximating complicated numbers f without using a calculator. Enjoy! Subscribe to my
From playlist Partial Derivatives
Convex Norms and Unique Best Approximations
In this video, we explore what it means for a norm to be convex. In particular we will look at how convex norms lead to unique best approximations. For example, for any continuous function there will be a unique polynomial which gives the best approximation over a given interval. Chapte
From playlist Approximation Theory
Diego Mondéjar Ruiz (6/10/22): Approximation of compact metric spaces by finite samples
We address the problem of reconstructing topological properties of a compact metric space by means of simpler ones. In this context, we use inverse sequences of finite topological spaces and polyhedra made from finite approximations of the space. This construction is related with Borsuk's
From playlist Vietoris-Rips Seminar
A Millis - An Introduction to Cluster DMFT
PROGRAM: STRONGLY CORRELATED SYSTEMS: FROM MODELS TO MATERIALS DATES: Monday 06 Jan, 2014 - Friday 17 Jan, 2014 VENUE: Department of Physics, IISc Campus, Bangalore PROGRAM LINK : http://www.icts.res.in/program/MTM2014 The realistic description of materials with strong electron-electro
From playlist Strongly correlated systems: From models to materials
Johannes Schmidt-Hieber: Statistical theory for deep neural networks - lecture 1
Recorded during the meeting "Data Assimilation and Model Reduction in High Dimensional Problems" the July 22, 2021 by the Centre International de Rencontres Mathématiques (Marseille, France) Filmmaker: Luca Récanzone A kinetic description of a plasma in external and self-consistent fiel
From playlist Virtual Conference
Christopher Schafhauser: On the classification of nuclear simple C*-algebras, Lecture 3
Mini course of the conference YMC*A, August 2021, University of Münster. Abstract: A conjecture of George Elliott dating back to the early 1990’s asks if separable, simple, nuclear C*-algebras are determined up to isomorphism by their K-theoretic and tracial data. Restricting to purely i
From playlist YMC*A 2021
Andrew Millis - Twisted Transition Metal Dicalcogenides: Tests of Quantum Embedding and Theories
Recorded 29 March 2022. Andrew Millis of Columbia University presents "Twisted Transition Metal Dicalcogenides: Experimental Tests of Quantum Embedding and Theories" at IPAM's Multiscale Approaches in Quantum Mechanics Workshop. Abstract: The essential task of quantum many-body theory is t
From playlist 2022 Multiscale Approaches in Quantum Mechanics Workshop
Virginie Ehrlacher - Sparse approximation of the Lieb functional in DFT with moment constraints
Recorded 28 March 2023. Virginie Ehrlacher of the École Nationale des Ponts-et-Chaussées presents "Sparse approximation of the Lieb functional in DFT with moment constraints (joint work with Luca Nenna)" at IPAM's Increasing the Length, Time, and Accuracy of Materials Modeling Using Exasca
From playlist 2023 Increasing the Length, Time, and Accuracy of Materials Modeling Using Exascale Computing
Emmanuel Giner - Curing basis set convergence of WFT w/ DFT: overview of framework and some results
Recorded 03 May 2022. Emmanuel Giner of the Centre National de la Recherche Scientifique presents "Curing basis set convergence of WFT with DFT: overview of framework and some results" at IPAM's Large-Scale Certified Numerical Methods in Quantum Mechanics Workshop. Learn more online at: ht
From playlist 2022 Large-Scale Certified Numerical Methods in Quantum Mechanics
Lecture with Ole Christensen. Kapitler: 00:00 - Intro To Approximation Theory; 10:00 - Remarks On Vectorspaces In Mat4; 13:30 - Def.: Dense Subset; 19:15 - Dense Subspace Of The Sequence Spaces L^p; 24:45 - Dense Subspace Of The Function Spaces L^p; 35:15 - Weierstrass Approximation Theore
From playlist DTU: Mathematics 4 Real Analysis | CosmoLearning.org Math
Lec 7 | MIT 3.320 Atomistic Computer Modeling of Materials
Technical Aspects of Density Functional Theory View the complete course at: http://ocw.mit.edu/3-320S05 License: Creative Commons BY-NC-SA More information at http://ocw.mit.edu/terms More courses at http://ocw.mit.edu
From playlist MIT 3.320 Atomistic Computer Modeling of Materials
Taylor polynomials -- Calculus II
This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.
From playlist Calculus II
Semiclassical origins of density functional approximations
Kieron Burke, University of California, Irvine, USA
From playlist Distinguished Visitors Lecture Series