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-rwxr-xr-xastro/calc_psd.py26
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,