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Scientific Computing with Python - Second Edition

You're reading from  Scientific Computing with Python - Second Edition

Product type Book
Published in Jul 2021
Publisher Packt
ISBN-13 9781838822323
Pages 392 pages
Edition 2nd Edition
Languages
Authors (3):
Claus Führer Claus Führer
Profile icon Claus Führer
Jan Erik Solem Jan Erik Solem
Olivier Verdier Olivier Verdier
View More author details

Table of Contents (23) Chapters

Preface Getting Started Variables and Basic Types Container Types Linear Algebra - Arrays Advanced Array Concepts Plotting Functions Classes Iterating Series and Dataframes - Working with Pandas Communication by a Graphical User Interface Error and Exception Handling Namespaces, Scopes, and Modules Input and Output Testing Symbolic Computations - SymPy Interacting with the Operating System Python for Parallel Computing Comprehensive Examples About Packt Other Books You May Enjoy References

4.9.2 Solving a least square problem with SVD

A linear equation system , with  being an  matrix and , is called an overdetermined linear system. In general, it has no classical solution and you seek a vector  with the property:

Here,  denotes the Euclidean vector norm .

This problem is called a least square problem. A stable method to solve it is based on factorizing , with  being an  orthogonal matrix,  an  orthogonal matrix, and  an matrix with the property  for all . This factorization is called a singular value decomposition (SVD).

We write

with a diagonal matrix . If we assume that  has full rank, then  is invertible and it can be shown that 

holds. 

If we split with being an  submatrix, then the preceding equation can be simplified to:

 

SciPy provides a function called svd, which we use to solve this task:

import scipy.linalg...
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