meaning of numpy.fft coefficients

Discussion in 'Python' started by Joey, Jul 9, 2011.

  1. Joey

    Joey Guest

    the list generated by numpy is of form [ a+bi, c+di, ...]

    could anybody tell me the meaning of the coefficients a and b? I am
    very confused about fourier transform!

    information provided by numpy reference says Ak = Sum of a[m] *
    exp{-2*pi * i * m * k / n} for m from 0 to n-1

    Which part is a and which part is b and what is the meaning of each
    part?

    Thx in adv.
    Joey, Jul 9, 2011
    #1
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  2. Excerpts from Joey's message of Fri Jul 08 20:14:29 -0400 2011:
    > the list generated by numpy is of form [ a+bi, c+di, ...]
    >
    > could anybody tell me the meaning of the coefficients a and b? I am
    > very confused about fourier transform!
    >


    a+bi is a typical complex number. a is the real part, b is the imaginary.
    Python uses j,

    >>> 4+5j

    (4+5j)

    http://en.wikipedia.org/wiki/Complex_number
    http://docs.python.org/library/stdtypes.html#typesnumeric
    --
    Corey Richardson
    "Those who deny freedom to others, deserve it not for themselves"
    -- Abraham Lincoln

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    Corey Richardson, Jul 9, 2011
    #2
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