diff -r f105cfcc2498 -r 1a73dddb1d05 matrices/slides.org --- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/matrices/slides.org Tue Oct 12 14:30:53 2010 +0530 @@ -0,0 +1,176 @@ +#+LaTeX_CLASS: beamer +#+LaTeX_CLASS_OPTIONS: [presentation] +#+BEAMER_FRAME_LEVEL: 1 + +#+BEAMER_HEADER_EXTRA: \usetheme{Warsaw}\usecolortheme{default}\useoutertheme{infolines}\setbeamercovered{transparent} +#+COLUMNS: %45ITEM %10BEAMER_env(Env) %10BEAMER_envargs(Env Args) %4BEAMER_col(Col) %8BEAMER_extra(Extra) +#+PROPERTY: BEAMER_col_ALL 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 :ETC + +#+LaTeX_CLASS: beamer +#+LaTeX_CLASS_OPTIONS: [presentation] + +#+LaTeX_HEADER: \usepackage[english]{babel} \usepackage{ae,aecompl} +#+LaTeX_HEADER: \usepackage{mathpazo,courier,euler} \usepackage[scaled=.95]{helvet} + +#+LaTeX_HEADER: \usepackage{listings} + +#+LaTeX_HEADER:\lstset{language=Python, basicstyle=\ttfamily\bfseries, +#+LaTeX_HEADER: commentstyle=\color{red}\itshape, stringstyle=\color{darkgreen}, +#+LaTeX_HEADER: showstringspaces=false, keywordstyle=\color{blue}\bfseries} + +#+TITLE: Matrices +#+AUTHOR: FOSSEE +#+EMAIL: +#+DATE: + +#+DESCRIPTION: +#+KEYWORDS: +#+LANGUAGE: en +#+OPTIONS: H:3 num:nil toc:nil \n:nil @:t ::t |:t ^:t -:t f:t *:t <:t +#+OPTIONS: TeX:t LaTeX:nil skip:nil d:nil todo:nil pri:nil tags:not-in-toc + +* Outline + - Creating Matrices + - using direct data + - converting a list + - Matrix operations + - Inverse of matrix + - Determinant of matrix + - Eigen values and Eigen vectors of matrices + - Norm of matrix + - Singular Value Decomposition of matrices + +* Creating a matrix + - Creating a matrix using direct data + : In []: m1 = matrix([1, 2, 3, 4]) + - Creating a matrix using lists + : In []: l1 = [[1,2,3,4],[5,6,7,8]] + : In []: m2 = matrix(l1) + - A matrix is basically an array + : In []: m3 = array([[5,6,7,8],[9,10,11,12]]) + +* Matrix operations + - Element-wise addition (both matrix should be of order ~mXn~) + : In []: m3 + m2 + - Element-wise subtraction (both matrix should be of order ~mXn~) + : In []: m3 - m2 +* Matrix Multiplication + - Matrix Multiplication + : In []: m3 * m2 + : Out []: ValueError: objects are not aligned + - Element-wise multiplication using ~multiply()~ + : multiply(m3, m2) + +* Matrix Multiplication (cont'd) + - Create two compatible matrices of order ~nXm~ and ~mXr~ + : In []: m1.shape + - matrix m1 is of order ~1 X 4~ + - Creating another matrix of order ~4 X 2~ + : In []: m4 = matrix([[1,2],[3,4],[5,6],[7,8]]) + - Matrix multiplication + : In []: m1 * m4 +* Recall from ~array~ + - The functions + - ~identity(n)~ - + creates an identity matrix of order ~nXn~ + - ~zeros((m,n))~ - + creates a matrix of order ~mXn~ with 0's + - ~zeros_like(A)~ - + creates a matrix with 0's similar to the shape of matrix ~A~ + - ~ones((m,n))~ + creates a matrix of order ~mXn~ with 1's + - ~ones_like(A)~ + creates a matrix with 1's similar to the shape of matrix ~A~ + Can also be used with matrices + +* More matrix operations + Transpose of a matrix + : In []: m4.T +* Exercise 1 : Frobenius norm \& inverse + Find out the Frobenius norm of inverse of a ~4 X 4~ matrix. + : + The matrix is + : m5 = matrix(arange(1,17).reshape(4,4)) + - Inverse of A, + - + #+begin_latex + $A^{-1} = inv(A)$ + #+end_latex + - Frobenius norm is defined as, + - + #+begin_latex + $||A||_F = [\sum_{i,j} abs(a_{i,j})^2]^{1/2}$ + #+end_latex + +* Exercise 2: Infinity norm + Find the infinity norm of the matrix ~im5~ + : + - Infinity norm is defined as, + #+begin_latex + $max([\sum_{i} abs(a_{i})^2])$ + #+end_latex +* ~norm()~ method + - Frobenius norm + : In []: norm(im5) + - Infinity norm + : In []: norm(im5, ord=inf) +* Determinant + Find out the determinant of the matrix m5 + : + - determinant can be found out using + - ~det(A)~ - returns the determinant of matrix ~A~ +* eigen values \& eigen vectors + Find out the eigen values and eigen vectors of the matrix ~m5~. + : + - eigen values and vectors can be found out using + : In []: eig(m5) + returns a tuple of /eigen values/ and /eigen vectors/ + - /eigen values/ in tuple + - ~In []: eig(m5)[0]~ + - /eigen vectors/ in tuple + - ~In []: eig(m5)[1]~ + - Computing /eigen values/ using ~eigvals()~ + : In []: eigvals(m5) +* Singular Value Decomposition (~svd~) + #+begin_latex + $M = U \Sigma V^*$ + #+end_latex + - U, an ~mXm~ unitary matrix over K. + - + #+begin_latex + $\Sigma$ + #+end_latex + , an ~mXn~ diagonal matrix with non-negative real numbers on diagonal. + - + #+begin_latex + $V^*$ + #+end_latex + , an ~nXn~ unitary matrix over K, denotes the conjugate transpose of V. + - SVD of matrix ~m5~ can be found out as, + : In []: svd(m5) +* Summary + - Matrices + - creating matrices + - Matrix operations + - Inverse (~inv()~) + - Determinant (~det()~) + - Norm (~norm()~) + - Eigen values \& vectors (~eig(), eigvals()~) + - Singular Value Decomposition (~svd()~) + +* Thank you! +#+begin_latex + \begin{block}{} + \begin{center} + This spoken tutorial has been produced by the + \textcolor{blue}{FOSSEE} team, which is funded by the + \end{center} + \begin{center} + \textcolor{blue}{National Mission on Education through \\ + Information \& Communication Technology \\ + MHRD, Govt. of India}. + \end{center} + \end{block} +#+end_latex + +