# Matrices and Matrix Manipulation

## Elementary Matrices

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    Elementary Matrices
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    eye             Identity matrix.
    gallery         Test matrices - matrix condition and eigenvalues.
    linspace        Linearly spaced vector.
    logspace        Logarithmically spaced vector.
    meshgrid        X and Y arrays for 3-D plots.
    ones            Ones matrix.
    rand            Uniformly distributed random numbers.
    randn           Normally distributed random numbers.
    zeros           Zeros matrix.
    :               Regularly spaced vector.
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    Special Variables and Constants
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    ans             Most recent answer.
    computer        Computer type.
    eps             Floating-point relative accuracy.
    flops           Count of floating-point operations.
    i, j            Imaginary unit.
    inf             Infinity.
    NaN             Not-a-Number.
    nargin          Number of function input arguments.
    nargout         Number of function output arguments.
    pi              3.1415926535897....
    realmax         Largest floating-point number.
    realmin         Smallest floating-point number
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    Time and Dates
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    clock           Wall clock.
    cputime         Elapsed CPU time.
    date            Calendar.
    etime           Elapsed time function.
    tic, toc        Stopwatch timer functions.
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    Matrix Manipulation
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    diag            Create or extract diagonals.
    fliplr          Flip matrix in the left/right direction.
    flipud          Flip matrix in the up/down direction.
    isreal          True for matrix containing real elements only.
    reshape         Change size.
    rot90           Rotate matrix 90 degrees.
    tril            Extract lower triangular part.
    triu            Extract upper triangular part.
    :               Index into matrix, rearrange matrix.
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## Specialized Matrices

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    Specialized Matrices
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    compan           Companion matrix.
    hadamard         Hadamard matrix.
    hankel           Hankel matrix.
    hilb             Hilbert matrix.
    invhilb          Inverse Hilbert matrix.
    magic            Magic square.
    pascal           Pascal matrix.
    rosser           Classic symmetric eigenvalue test problem.
    toeplitz         Toeplitz matrix.
    vander           Vandermonde matrix.
    wilkinson        Wilkinson's eigenvalue test matrix.
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(c) Copyright 1994 by The MathWorks, Inc.