Add TimeVaryingInput0D support for ITime

Add tests for TimeVaryingInput0D for 0D TVI
with times of floats, ITime with no epoch, and ITime
with epoch.

Tests 0d TVI of floats can evaluate at ITime inputs, floating point
inputs, and tests that an error is thrown with a datetime input.

Test that error is thrown when evaluating a TVI of ITimes
with no epoch at a DateTime.

Test that TVI of ITime with epoch can be evaluated at
ITimes, floats, or DateTimes.

Test that TVI of ITime with no epoch can be evaluated at
ITimes or floats.

Make all the above tests pass by adding conversions to
the `evaluate!` methods.

use date instead of DateTime

apply suggested style change

varname bugfix

Author: imreddyTeja

ext/TimeVaryingInputs0DExt.jl

@@ -20,16 +20,17 @@ import ClimaUtilities.TimeVaryingInputs: extrapolation_bc
 import ClimaUtilities.TimeVaryingInputs
 
 import ClimaUtilities.TimeManager: ITime, date
+using Dates
 
 """
     InterpolatingTimeVaryingInput0D
 
 The constructor for InterpolatingTimeVaryingInput0D is not supposed to be used directly, unless you
 know what you are doing.
 
-`times` and `vales` may have different float types, but they must be the same length, and we
+`times` and `values` may have different types, but they must be the same length, and we
 assume that they have been sorted to be monotonically increasing in time, without repeated
-values for the same timestamp.
+values for the same timestamp. `times` can have elements of type `ITime` or floats
 """
 struct InterpolatingTimeVaryingInput0D{
     AA1 <: AbstractArray,
@@ -107,9 +108,13 @@ function TimeVaryingInputs.TimeVaryingInput(
 
     if extrapolation_bc(method) isa PeriodicCalendar
         if extrapolation_bc(method) isa PeriodicCalendar{Nothing}
-            isequispaced(times) || error(
-                "PeriodicCalendar() boundary condition cannot be used because data is defined at non uniform intervals of time",
+            if !isequispaced(
+                eltype(times) <: ITime ? [float.(promote(times...))...] : times,
             )
+                error(
+                    "PeriodicCalendar() boundary condition cannot be used because data is defined at non uniform intervals of time",
+                )
+            end
         else
             # We have the period in PeriodicCalendar
             error(
@@ -197,9 +202,18 @@ function TimeVaryingInputs.evaluate!(
         # interpolation between t_init and t_end. In this case, y0 = vals[end], y1 =
         # vals[begin], t1 - t0 = dt, and time - t0 = time - t_end
         if time > t_end
-            @. dest =
-                itp.vals[end] +
-                (itp.vals[begin] - itp.vals[end]) / dt * (time - t_end)
+            if time isa ITime
+                FT = eltype(itp.vals)
+                @. dest =
+                    itp.vals[end] + FT(
+                        (itp.vals[begin] - itp.vals[end]) / float(dt) *
+                        float((time - t_end)),
+                    )
+            else
+                @. dest =
+                    itp.vals[end] +
+                    (itp.vals[begin] - itp.vals[end]) / dt * (time - t_end)
+            end
             return nothing
         end
     end
@@ -213,7 +227,7 @@ end
 
 function TimeVaryingInputs.evaluate!(
     destination,
-    itp::InterpolatingTimeVaryingInput0D,
+    itp::InterpolatingTimeVaryingInput0D{<:AbstractArray{<:Number}},
     time::ITime,
     args...;
     kwargs...,
@@ -227,4 +241,53 @@ function TimeVaryingInputs.evaluate!(
     )
 end
 
+function TimeVaryingInputs.evaluate!(
+    destination,
+    itp::InterpolatingTimeVaryingInput0D{<:AbstractArray{<:ITime}},
+    eval_date::DateTime,
+    args...;
+    kwargs...,
+)
+    t0_date = date(itp.range[1])
+    diff_ms = eval_date - t0_date
+    converted_time =
+        ITime(diff_ms.value; period = typeof(diff_ms)(1), epoch = t0_date)
+    return TimeVaryingInputs.evaluate!(
+        destination,
+        itp,
+        converted_time,
+        args...;
+        kwargs...,
+    )
+
+end
+
+function TimeVaryingInputs.evaluate!(
+    destination,
+    itp::InterpolatingTimeVaryingInput0D{<:AbstractArray{<:ITime}},
+    time::Number,
+    args...;
+    kwargs...,
+)
+    converted_time = first(promote(ITime(time), itp.range[1]))
+    return TimeVaryingInputs.evaluate!(
+        destination,
+        itp,
+        converted_time,
+        args...;
+        kwargs...,
+    )
+
+end
+
+TimeVaryingInputs.evaluate!(
+    destination,
+    itp::InterpolatingTimeVaryingInput0D{<:AbstractArray{<:Number}},
+    time::DateTime,
+    args...;
+    kwargs...,
+) = error(
+    "Cannot evaluate InterpolatingTimeVaryingInput0D with times as numbers and inputs as DateTime",
+)
+
 end