Closed mpyat2 closed 1 year ago
Hi @mpyat2. This seemingly odd result is due to the fact that every observation in a phase plot has:
0
to 1
-1
to 0
standard phase - 1
In VeLa, when you ask for phase
, you're getting standard phase.
If your filter is changed to phase > 0.9
, the result you seek will be achieved.
Make sense?
Some possibilities:
phase
< 1?phase
into standard and previous cycle phase?Previous cycle phase is a convenience to allow phase plots to show a representative phased light curve by placing two identical phase plots together. It's a visual aid more than anything.
We could try to combine standard and previous cycle into phase
for filtering purposes, but that would require some thought.
Hi @dbenn, Well, I think it's enough to document that phase > 0 and phase < 1, at least for now. So, if anyone wants to filter for a phase in [-0.1 .. 0.1], she/he can write:
phase <0.1 or phase >0.9
Added this at the end of the phase plots section:
Note that for filters (see Filtering Observations section) where the value of the observation's phase is sought, the range of phase values to be specified is from 0 to 1, the so-called standard phase. The so-called previous cycle phase value from -1 to 0 cannot be specified within a filter. So, for example, to create a filter that includes observations in the apparent phase plot range from -0.1 to 0.1, the VeLa filter expression phase < 0.1 or phase > 0.9 could be used.
@mpyat2, I've changed the user manual text like so (with better use of bold/italic and font change)
Note that for filters (see Filtering Observations section) where the value of the observation's phase is sought, the range of phase values from 0 to 1 on the phase plot is the so-called standard phase or simply, the phase. The so-called previous cycle phase value is defined as:
1 - standard phase
and occupies the range from -1 to 0 on the phase plot. Selecting an observation via a filter with a particular phase, will also select the observation with the corresponding previous cycle phase, since this corresponds to the same observation.
A Simple Filter (View → Simple Filter dialog) can express the equivalent of this VeLa filter (View → VeLa Filter):
phase > 0.69 and phase < 0.71
but not this one:
(standardphase > 0.69 and standardphase < 0.71) or (previouscyclephase > -0.81 and previouscyclephase < -0.79)
Simple Filters do not allow disjunction (“or”). Only conjunction (and) between filter expression terms.
So, Simple Filters allow only phase to be specified (range 0 to 1), while VeLa filter expressions can contain the variables phase, standardphase and/or previouscyclephase.
@dbenn , sounds good!
Try the following VeLa filter: Phase >-0.1. ALL points will be selected.