code: def sinegauss_FT_a(f, t0, f0, a):
      """Fourier transform of the sine-gaussian wavelet.
      This uses the convention H(f) = integral[ h(t) exp(-2pi i f t) dt]
  
      Differs from the ``astroML.fourier.sinegauss`` in that instead of taking a
      coefficient ``Q`` and calculating the coefficient ``a``, it assumes the
      given coefficient ``a`` is correct. The relationship between the two is
      given as:
  
          a = (f0 * 1. / Q) ** 2
      """
      return (
          np.sqrt(np.pi / a)
          * np.exp(-2j * np.pi * f * t0)
          * np.exp(-np.pi**2 * (f - f0) ** 2 / a)
      )
  
file_path: astroML/astroML/tests/test_fourier.py
imports: import pytest
  import numpy
  from numpy.testing import assert_allclose
  from astroML.fourier import FT_continuous, IFT_continuous, PSD_continuous, sinegauss, sinegauss_FT
label_desc: Use image node_id 3 for calling a global function with example usage: sinegauss_FT_a(f, t0, f0, a) and returns: unknown