diff options
Diffstat (limited to 'astro')
| -rwxr-xr-x | astro/calc_psd.py | 26 |
1 files changed, 14 insertions, 12 deletions
diff --git a/astro/calc_psd.py b/astro/calc_psd.py index 5a3552d..ad7659e 100755 --- a/astro/calc_psd.py +++ b/astro/calc_psd.py @@ -45,15 +45,16 @@ class PSD: Specify the pixel size and its unit of the image. e.g., (0.33, "arcmin") step : float, optional - If specified, then a log-even grid with the given step ratio will - be used to do the azimuthal averages. Otherwise, a evenly - pixel-by-pixel (along radial direction) is adopted. + By default, a logarithmic grid with the specified step ratio + (default: 1.1) will be used to do the azimuthal averages. + If specified a value <=1 or None, then a evenly pixel-by-pixel + (along radial direction) is adopted. meanstd : bool, optional By default, the median and 16% and 84% percentiles (i.e., 68% error) will be calculated for each averaged annulus. If this option is ``True`` then calculate the mean and standard deviation instead. """ - def __init__(self, image, pixel=(1.0, "pixel"), step=None, + def __init__(self, image, pixel=(1.0, "pixel"), step=1.1, meanstd=False, bunit=None): self.image = np.array(image, dtype=float) self.shape = self.image.shape @@ -61,9 +62,10 @@ class PSD: raise ValueError("input image is not square!") self.pixel = pixel - self.step = step - if step is not None and step <= 1: - raise ValueError("step must be greater than 1") + if step is None or step <= 1: + self.step = None + else: + self.step = step self.meanstd = meanstd self.bunit = bunit @@ -336,11 +338,11 @@ def main(): description="Calculate radial power spectral density") parser.add_argument("-C", "--clobber", dest="clobber", action="store_true", help="overwrite the output files if already exist") - parser.add_argument("-s", "--step", dest="step", type=float, default=None, - help="step ratio between 2 consecutive radial " + - "frequency points, must be > 1, thus a log-even " + - "grid is adopted; if not specified, then the power " + - "at every frequency point will be calculated, " + + parser.add_argument("-s", "--step", dest="step", type=float, default=1.1, + help="step ratio (>1) between 2 consecutive radial " + + "frequency points, i.e., a logarithmic grid used. " + + "if specified a value <=1, then the power at every " + + "radial frequency point will be calculated, " + "i.e., using a even grid, which may be very slow " + "for very large images!") parser.add_argument("-p", "--pixelsize", dest="pixelsize", type=float, |