ported utcut1 (#38)

* added utcut1 * added dat * reset
JuliaAstro · Jun 19, 2018 · b50676e · b50676e
1 parent 30097e8
commit b50676e
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diff --git a/src/conversions.jl b/src/conversions.jl
@@ -621,8 +621,7 @@ end
 
 Transforms DateTime field to two-part Julian Date, special provision for leapseconds is provided.
 
-# Example
-
+#Example
 ```jldoctest
 julia> AstroTime.Epochs.datetime2julian(UTC, 2016, 12, 31, 23, 59, 60)
 (2.4577535e6, 0.9999884260598836)
@@ -666,6 +665,28 @@ function datetime2julian(scale::T, year, month, date, hour, min, sec) where {T <
     jd, time
 end
 
+"""
+   utcut1(jd1, jd2)
+
+Transform a two-part Julian date from `UTC` to `UT1`.
+
+# Example
+
+```jldoctest
+julia> utc  = Epoch{UTC}(2.4578265e6, 0.30477440993249416)
+2017-03-14T07:18:52.509 UTC
+julia> AstroTime.Epochs.utcut1(utc.jd1, utc.jd2)
+(2.4578265e6, 0.30477440993249416)
+```
+"""
+@inline function utcut1(jd1, jd2, dut1, dat)
+    jd = +(jd1, jd2)
+    dta = dut1 - dat
+    tai1, tai2 = utctai(jd1, jd2)
+    date, date1 = taiut1(tai1, tai2, dta)
+    date, date1
+end
+
 # TAI <-> UTC
 @transform UTC TAI ep begin
     jd1, jd2 = julian1(ep), julian2(ep)

diff --git a/test/runtests.jl b/test/runtests.jl
@@ -155,7 +155,8 @@ AstroTime.update()
         tdb = TDBEpoch(2000, 1, 1, 12, 0, 0.0)
         tcb = TCBEpoch(2000, 1, 1, 12, 0, 0.0)
         Δtr(ep) = Epochs.diff_tdb_tt(julian1(ep), julian2(ep))
-        dat(ep) = Epochs.dut1(ep)-Epochs.leapseconds(julian(ep))
+        dut1(ep) = Epochs.dut1(ep)
+        dat(ep) = dut1(ep) - Epochs.leapseconds(julian(ep))
 
         @test Epochs.tttai(julian1(tt), julian2(tt)) == ERFA.tttai(julian1(tt), julian2(tt))
         @test Epochs.tttai(julian2(tt), julian1(tt)) == ERFA.tttai(julian2(tt), julian1(tt))
@@ -224,6 +225,9 @@ AstroTime.update()
         @test Epochs.jd2cal(julian1(tt), julian2(tt)) == ERFA.jd2cal(julian1(tt), julian2(tt))
         @test Epochs.jd2cal(julian2(tt), julian1(tt)) == ERFA.jd2cal(julian2(tt), julian1(tt))
 
+        @test Epochs.utcut1(julian1(utc), julian2(utc), dut1(utc),leapseconds(julian(utc))) == ERFA.utcut1(julian1(utc), julian2(utc), dut1(utc))
+        @test Epochs.utcut1(julian2(utc), julian1(utc),dut1(utc),leapseconds(julian(utc))) == ERFA.utcut1(julian2(utc), julian1(utc), dut1(utc))
+
         @test Epochs.datetime2julian(UTC, 2016, 12, 31, 23, 59, 60) == ERFA.dtf2d("UTC", 2016, 12, 31, 23, 59, 60)
         @test Epochs.datetime2julian(TT, 2016, 12, 31, 23, 59, 59) == ERFA.dtf2d("TT", 2016, 12, 31, 23, 59, 59)
         @test_throws ArgumentError Epochs.datetime2julian(TT, 2016, 12, 31, 23, 59, 60)