diff options
Diffstat (limited to 'astro/spectrum/crosstalk_deprojection.py')
| -rwxr-xr-x | astro/spectrum/crosstalk_deprojection.py | 41 |
1 files changed, 20 insertions, 21 deletions
diff --git a/astro/spectrum/crosstalk_deprojection.py b/astro/spectrum/crosstalk_deprojection.py index 43e5fb4..4757178 100755 --- a/astro/spectrum/crosstalk_deprojection.py +++ b/astro/spectrum/crosstalk_deprojection.py @@ -5,6 +5,7 @@ # # Change log: # 2017-12-13: +# * Fix possible invalid spectral errors due to negative group counts # * Allow the missing of ``info_emin`` and ``info_emax`` # * Do not use ``sys.stderr`` # * Cleanup reading grouping/quality from file @@ -162,7 +163,7 @@ from astropy.io import fits from configobj import ConfigObj -__version__ = "0.6.2" +__version__ = "0.6.3" __date__ = "2017-12-13" WARNING = """ @@ -605,16 +606,24 @@ class Spectrum: # {{{ N photons is given by `1 + sqrt(N + 0.75)'; otherwise, the error is given by `sqrt(N)'. - Results: `self.spec_err' + Attributes + ---------- + spec_err : `~numpy.ndarray` + Estimated errors for the spectral data. + NOTE: If the spectral data (in counts) have negative groups, the + errors of those groups are set to 0.0! """ - eps = 1.0e-10 - if gehrels: - self.spec_err = 1.0 + np.sqrt(self.spec_data + 0.75) - else: - self.spec_err = np.sqrt(self.spec_data) - # replace the zeros with a very small value (because - # `np.random.normal' requires `scale' > 0) - self.spec_err[self.spec_err <= 0.0] = eps + with np.errstate(invalid="ignore"): + if gehrels: + self.spec_err = 1.0 + np.sqrt(self.spec_data + 0.75) + else: + self.spec_err = np.sqrt(self.spec_data) + # Warn about and fix the invalid error values + invalid = ~np.isfinite(self.spec_err) + if np.sum(invalid) > 0: + print("WARNING: invalid spectral errors are set to 0.0! " + + "(due to negative spectral group counts)") + self.spec_err[invalid] = 0.0 def copy(self): """ @@ -916,21 +925,11 @@ class SpectrumSet(Spectrum): # {{{ Estimate the statistical errors of each spectral group (after applying grouping) for the source spectrum (and background spectrum). - If `gehrels=True', the statistical error for a spectral group with - N photons is given by `1 + sqrt(N + 0.75)'; otherwise, the error - is given by `sqrt(N)'. - Results: `self.spec_err' (and `self.bkg.spec_err') """ super().estimate_errors(gehrels=gehrels) - eps = 1.0e-10 - # estimate the errors for background spectrum if present if self.bkg: - if gehrels: - self.bkg.spec_err = 1.0 + np.sqrt(self.bkg.spec_data + 0.75) - else: - self.bkg.spec_err = np.sqrt(self.bkg.spec_data) - self.bkg.spec_err[self.bkg.spec_err <= 0.0] = eps + self.bkg.estimate_errors(gehrels=gehrels) def subtract_bkg(self, inplace=True, add_history=False, verbose=False): """ |