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Discussion

As raised in section [*], the CLASS data format does not provide a weight array, even if one is available in the Fortran type observation which is used to load in memory the observations read from file. The observation type is used only when processing the data e.g. in the current context of AVERAGE and ACCUMULATE.

For consistency reasons over all the commands in CLASS which can make use of the weight array, its content is assumed to be inexistant or unset when entering the command: the weight array is recomputed each time it is needed. This implies a unique value for all the channels, e.g. the $\sigma$ value computed by BASE.

The discussions in this document raise the idea to save the weight array in the CLASS data format. Indeed, we have seen that the single value which is recomputed from scratch can not reflect the real weight of each channel, e.g. when the spectrum is the AVERAGE of several others in COMPOSITE mode. But this has two major caveats:

For the time being, saving (always or not) the weight array in the CLASS data format remains an open question.


next up previous contents
Next: Conclusion Up: IRAM Memo 2009-4 Averaging Previous: Concatenation   Contents
Gildas manager 2014-07-01