Demote UTC to I/O format and general overhaul #58
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Workaround for JuliaLang/julia#37579
helgee
changed the title
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| function findyear(calendar, j2000day::Int32) | ||
| function findyear(calendar, j2000day) |
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Am I correct to think we assume j2000day to be Union{Int32,Int64}? Or is it Int? If this is limited to Int32/Int64 it can also be Int64(j2000day) without any if*.
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I am not sure about this. It seems that Int64(j2000day) allocates and I saw lots jl_box_int64 in my profiles. This is ugly but performance is an order of magnitude better: j2kday = ifelse(j2000day isa Int32, widen(j2000day), j2000day)
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And it is Int so changes only with Sys.WORD_SIZE.
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| function findyear(calendar, j2000day::Int32) | ||
| function findyear(calendar, j2000day) | ||
| j2kday = ifelse(j2000day isa Int32, widen(j2000day), j2000day) |
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Int64(<literal>) allocates apparently so this has a significant performance impact.
| @@ -216,113 +175,235 @@ const UNIX_EPOCH = Date(1970, 1, 1) | |||
| struct Time{T} | |||
| hour::Int | |||
| minute::Int | |||
| second::T | |||
| second::Int | |||
| fraction::T | |||
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I changed the representation of Time to have the same accuracy characteristics as Epoch. As a result, converting Epoch to AstroTime.DateTime and vice versa is losless. Dates.DateTime on the other hand is still limited to millisecond precision.
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| const H00 = Time(0, 0, 0.0) | ||
| const H12 = Time(12, 0, 0.0) | ||
| function subsecond(fraction, n, r) |
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This stumped me for a while. See also the method below. As a result, we now get sensible values for milli-/micro-/nanoseconds as if they were integral values and hiding the inherent floating point inaccuracies.
julia> subsecond(0.1839999999999975, 9)
0
julia> subsecond(0.1839999999999975, 3)
184
julia> subsecond(0.123456789, 9)
789
julia> subsecond(0.123456789, 3)
123| print(io, timescale(ep)) | ||
| abstract type FractionOfSecondToken end | ||
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| @inline function Dates.tryparsenext(d::Dates.DatePart{'f'}, str, i, len, locale) |
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We can now parse timestamps with full Float64 precision by using the f field, e.g. dateformat"yyyy-mm-ddTHH:MM:SS.ffffffff. Thereby circumventing JuliaLang/julia#37579
| ``` | ||
| """ | ||
| @inline function getoffset(::CoordinatedUniversalTime, ::UniversalTime, | ||
| @inline function getoffset(::InternationalAtomicTime, ::UniversalTime, |
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UT1 is linked to TAI now.
| const LEAP_TAI = LEAP_J2000 .+ round.(Int, LeapSeconds.LEAP_SECONDS) .- 1 | ||
| const LEAP_TAI_SET = Set(LEAP_TAI) | ||
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| function from_utc(str::AbstractString; |
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This is the headline change. There is no Epoch{UTC} anymore but we can still convert to/from UTC via the dedicated from_utc and to_utc. The discussion about this is in #50 (comment).
TL;DR: The Epoch data format is incompatible with a discontinuous timescale like UTC (and only UTC 👎 ). Thus, it makes no sense to rewrite the whole library and add a lot of edge cases for UTC. The best way of dealing with UTC and leap seconds is by keeping them on the outer edge of your code or pretend they do not exist like Google (https://github.com/google/unsmear). Friends do not let friends use UTC for mission-critical time keeping.
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| to_utc(ep, args...) = to_utc(String, ep, args...) | ||
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| """ |
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now returns actual TAI (from UTC) instead of local time. No idea what will happen during a leap second though 😬
| @test step(rng) == 13seconds | ||
| @test last(rng) == UTCEpoch(2018, 1, 1, 0, 0, 52.0) | ||
| end | ||
| @testset "Leap Seconds" begin |
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All of these become obsolete by removing UTC 😅
| @timescale GMT UTC | ||
| AstroTime.Epochs.getoffset(::GMTScale, ::CoordinatedUniversalTime, _, _) = 0.0 | ||
| AstroTime.Epochs.getoffset(::CoordinatedUniversalTime, ::GMTScale, _, _) = 0.0 | ||
| # TODO: Change me |
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These examples are not great anymore and I will try to come up with new ones during the doc update.
Boy, that escalated quickly!
I realize that this is a lot to review so I will leave comments inline to highlight the most important changes. Documentation updates will follow in a separate PR.
Fixes #50
Fixes #53