RFM Flags: Double Precision Output Spectra

DBL Flag


Output spectra written with full (ie double) precision

Output spectra truncated to single precision

Incompatible with TAB flag (see note 2)

  1. Internally, the radiative transfer integration is always performed with Double Precision although the underlying line parameters on which the calculations are based (with the exception of line position) are rarely known to better than 1%, i.e. single precision.
  2. In particular the absorption coefficients, as generated with the TAB flag without any radiative transfer calculation, are only reasonably expressed as single precision, hence the incompatibility with the DBL flag.
  3. Double Precision output is only really necessary when considering transmittances close to 1.0 (in which case writing absorption (= 1-transmittance) spectra would be better), or when comparing different RFM runs with minor perturbations.

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