Added `Observer.toStateVector` and `Observer.toVector` for converting
an observer's geographic location to position and velocity vectors
relative to the Earth's center.
Reworked the C unit test to output a text file that can be used
as reference, to make sure the Kotlin output matches.
For years before 1582 or years after 3668, the Seasons functions
were unable to find many equinoxes and/or solstices.
The problem was that over time, the Earth's axis precesses
enough that the calendar dates of these events drifts outside
the fixed search ranges I had provided for them.
I expanded the search ranges so all season changes can be found
for a much wider range of years, as verified by unit tests:
C/C++: -2000..9999
C#: 1..9999
JavaScript: -2000..9999
Python: 1..9999
Kotlin: 1..9999
Note: C#, Python, and Kotlin currently do not allow
years values below +1. In fact, I discovered we were not
noticing when an invalid year was passed into the Kotlin code.
I updated that code to throw an exception when the year does
not match what was expected. It is disturbing that the
GregorianCalendar class silently ignores invalid years!
Constricted the search tolerance from 1 second to 0.01
seconds for the seasons search, to ensure more consistent
behavior.
Fixed a bug in the Kotlin search() function's
quadratic interpolation that was causing the convergence
to be slower than it should have been.
Added Astronomy.searchAltitude, which enables more generic
searches for altitude events. The most common use for these
are finding civil, nautical, and astronomical twilight times.
Implemented the following Kotlin functions:
Astronomy.searchHourAngle
Astronomy.searchRiseSet
The Kotlin code can now search for rise/set
times for a given Earthbound observer for the
Sun, Moon, or any planet.
It can also search for times when a given body
reaches a desired hour angle. This has its own
value (for example, culmination), but is also
used to assist finding time brackets that bound
rise/set events.
Added special case exception type:
EarthNotAllowedException.
This follows the pattern of the other languages,
and makes diagnosing a violation easier than
the more generic InvalidBodyException.
Minor simplifications to the C# function
Astronomy.InternalSearchAltitude.
Improved the comments for the C# unit test
function RiseSetTest. They make the algorithm
easier to understand.
Added the following Kotlin functions:
equatorialToEcliptic
pairLongitude
moonPhase
searchMoonPhase
searchMoonQuarter
nextMoonQuarter
Discovered I could tighten the tolerance for the moon phase
unit tests from 120 seconds to 90 seconds and they still pass.
Dokka preserves leading whitespace in the text after
`@return` comments. This causes these fields to render
as preformatted text. Removed the leading whitespace so
this text is rendered as normal markdown.
Implemented the following related functions in Kotlin:
sunPosition
searchSunLongitude
seasons
C#: fail Astronomy.Seasons with an exception if any of the
equinox/solstice searches fail. If this ever happens, it is
an internal error. It should not be the burden of the caller
to check for nulls! Fixed mistake in documentation for
searchSunLongitude.
Implemented the low-level search function that will be used
to implement all the special-purpose search functions to come.
Added missing documentation to class NodeEventInfo members.
Minor cleanup in the C# function `Astronomy.Search`:
- removed an unused output parameter.
- deleted confusing sentence in documentation.
Starting to add the functions that create rotation
matrices to convert from one orientation to another.
Here are the ones implemented in this commit:
rotationEqjEcl
rotationEclEqj
rotationEqjEqd
Also starting to add missing documentation to
resolve Dokka warnings.
The `horizon` function was taking the sine and cosine
of the right ascension, but treating it as degrees.
This was wrong because right ascension is in sidereal hours.
Fix: multiply hours by 15 to get degrees.
Keeping the unit test that confirmed this bug.
Added comparison of C and Kotlin output to `diffcalc`
and `diffcalc.bat`. This test now passes on Linux.
This is a big milestone!
The function getPlutoSegment had a bug simulating gravity
in the forward direction. It was creating an array `seg`
that was one item too long: 202 instead of 201 elements.
This caused states from inconsistent time steps to be mixed.
I discovered this via the `diffcalc` script.
I added a new unit test that quickly reproduced this issue.
This was helpful for debugging and finding the problem.
I'm keeping the new unit test, in case it helps detect
breakage in the future.
Implemented Kotlin functions and code generator
for calculating the state vectors of Jupiter's
largest 4 moons.
Added cautionary comments about needing to correct
Jupiter's moons for light travel time.
This is the first pass to get everything needed
for the AstroCheck tests. I tried comparing
C output to Kotlin output, and there are some
serious problems to debug:
$ ./ctest diff 2.8e-16 temp/{c,k}_check.txt
First file: temp/c_check.txt
Second file: temp/k_check.txt
Tolerance = 2.800e-16
lnum a_value b_value factor diff name
FAIL 137746 4.2937184148112564e+01 4.2944101081740065e+01 0.03364 2.327e-04 helio_x
FAIL 373510 1.4197190315274938e+01 1.4193716564905307e+01 0.03364 1.168e-04 helio_y
FAIL 137746 -6.5897675150466091e+00 -6.5929481589493522e+00 0.03364 1.070e-04 helio_z
FAIL 59150 1.8035183339348251e+01 1.8035909197904104e+01 0.01730 1.255e-05 sky_j2000_ra
FAIL 137747 -8.1222057639092533e+00 -8.1250990689970894e+00 0.00556 1.607e-05 sky_j2000_dec
FAIL 137747 4.8436159305823310e+01 4.8441487614058218e+01 0.03481 1.855e-04 sky_j2000_dist
FAIL 322846 8.7596368704201495e+01 2.6760770774700188e+02 0.00278 4.995e-01 sky_hor_az
FAIL 405828 -6.5075824596574279e+01 5.6922941329250996e+01 0.00556 6.778e-01 sky_hor_alt
OK 92717 4.1268347083494783e-03 4.1268347083494774e-03 223.21429 1.936e-16 jm_x
OK 45091 -8.0149190392649894e-03 -8.0149190392649929e-03 79.42812 2.756e-16 jm_y
OK 135377 1.5470777280065808e-03 1.5470777280065804e-03 223.21429 9.680e-17 jm_z
OK 216836 4.5725777238332412e-03 4.5725777238332394e-03 126.58228 2.196e-16 jm_vx
OK 351647 5.1351566793199944e-03 5.1351566793199962e-03 126.58228 2.196e-16 jm_vy
OK 351647 2.5217607180929289e-03 2.5217607180929298e-03 126.58228 1.098e-16 jm_vz
Score = 6.778e-01
ctest(Diff): EXCEEDED ERROR TOLERANCE.
So I'm checking this in as work-in-progress.
Implemented more of the core functions needed for
the AstroCheck tests. Most of AstroCheck is now implemented,
except for the JupiterMoons tests.
Code cleanup thanks to @ebraminio:
- Use `when { }` syntax.
- Renamed `IllumInfo` to `IlluminationInfo`.
- Other minor naming fixes.
Configured Dokka to warn about undocumented symbols.
We also configured Dokka to omit internal symbols, including
inside enums, but that does not work, despite this bug
being marked fixed in dokka:
https://github.com/Kotlin/dokka/issues/1802
We suspect they didn't really fix the bug, and that
there is a bug in their test.
Thanks to @ebraminio, I learned that Kotlin enum classes
allow the members to contain data properties. This greatly
simplifies code so that I no longer need such verbose
`when (body)` statements.
I also understand Kotlin enums better, and I realized
there is no need for `Body.Invalid`, because the compiler
simply does not allow invalid enum values to exist.
In any future hypothetical situation where I want to
represent an optional `Body` value, I can use the nullable type `Body?`.
Added Astronomy.geoMoonState and Astronomy.helioState functions.
These allow calculating the position and velocity of any
solar system body.
Added sanity checks for state vectors in the unit tests.
Added calculation of heliocentric and barycentric
state vectors for Pluto. This is done using
a gravity simulator that treats Pluto as a negligible
mass that is affected by the major masses of the
Solar System: Sun, Jupiter, Saturn, Uranus, Neptune.
Updated the code generator to write the Kotlin
version of the Pluto state table, a lookup table
of known-correct state vectors of Pluto at long
intervals, derived from the TOP2013 model.
The gravity simulator interpolates state vectors
of Pluto between these known-correct states.
Minor code style cleanup in the Kotlin source.
Fixed a possible thread-safety issue in the C# code.
Implemented the VSOP87 calculation functions for
heliocentric position vectors, heliocentric velocity vectors,
and heliocentric distances.
Implemented Astronomy.helioVector for everything except Pluto and SSB.
Corrected small errors in C# documentation.
Implemented the Montenbruck/Pfleger version of the NAO1954
geocentric Moon model in Kotlin.
In the process, code review helped simplify parts of the C# code.
I may want to go back and see if I can simplify the CalcMoon
code in the other languages too.
Added code generator for VSOP87 major planet models in Kotlin.
Added a lookup function for VSOP87 models to Kotlin template.
Moved IAU2000b delcaration outside class Astronomy.
Added the rotationAxis, which calculates dynamic orientation
of planet, Sun, and Moon rotation axes. Added the first
unit test that verifies against JPL Horizons data.
Eliminated more redundant time parameters in precession functions.
More cleanup of C# code: I realized the private function
vector2radec was redundant with the public function EquatorFromVector.
Deleted vector2radec.
Added functions for generating rotation matrices,
rotating position vectors, and rotating state vectors,
for the Earth's axial nutation.
Simplified gyration functions in C#:
it turns out the `time` parameters were redundant,
because time is included in the `t` field of the vector
passed in. I reworked the C# code to eliminate those time
parameters.
The Kotlin code follows suit.
Implemented the functions `terra` and `inverseTerra`.
`terra` converts geographic coordinates and time into
a geocentric state vector.
`inverseTerra` converts a position vector and time
into geographic coordinates.
I realized the C# function `inverse_terra` could be
simplified. It does not need to be passed a separate
time, because the sidereal time can be derived
from, or has already been stored inside, the vector's
time field `ovec.t`.
There were a couple of other minor cleanups to the C# code.
Implemented Astronomy.siderealTime() in Kotlin.
Updated all languages' unit tests for sidereal time
to verify exact conformity between them, rather than
to an externally derived value. I wanted to make
sure all languages, including Kotlin, are calculating
the exact same value.
I don't need an external authoritative test for
sidereal time, because it will be indirectly tested
through its involvement in thousands of other calculations
that depend on it. I just need a quick sanity check
before implementing those other things that depend on it.
Implemented the iau2000b nutation formula.
Implemented calculation of the precession
rotation matrix.
This is the very first use of a code generator
macro for the Kotlin code. I am going to try
keeping all these macros toward the bottom
of the source tepmlate, so that as I look at
line numbers for compiler errors, they will match
between the target code and the template code.
I may go back and rework the other languges to
do this also. I'm not sure why I didn't think
of this before!
Ported the following types to the Kotlin code:
GlobalSolarEclipseInfo
EclipseEvent
LocalSolarEclipseInfo
TransitInfo
ShadowInfo
IllumInfo
AxisInfo
NodeEventKind
NodeEventInfo
Made some wording fixes in the documentation for the
other languages.
I didn't realize Dokka doesn't clean up its output directory
before writing documentation files. This caused stale documentation
to still exist from previous builds. The result was a failed
unit test because the generated documentation did not match
what was checked into git.
In general, I want to make sure that builds I run on my development
system exactly match what GitHub Actions does on its cloud platform.
So before running the `gradlew` build step, I delete the entire
directory source/kotlin/build. This directory is always absent
on GitHub Actions, which makes my local build better match the
remote build.
Converting between radians and degrees.
Clamping angles to a desired range of degrees.
Converting between vector, spherical, horizontal.
Refraction and inverse refraction.
Implemented most of the RotationMatrix functions.
Added unit tests for combining rotation matrices, using a
rotation matrix to rotate a vector, and pivoting a rotation
matrix around its axes.
Replaced AstroVector operator '*' with infix function 'dot',
because it removes ambiguity between vector dot products
and vector cross products.
Later I will add a 'cross' infix function too.
Corrected minor typo in documentation for Python, C, C#, JavaScript.
"trasnform" -> "transform"
Moved Astronomy object to bottom of source file.
This object is going to end up with a lot of functions,
so it's best to keep outer classes above it.
Removed unnecessary empty {} after classes.
Replace Array<Array<Double>> with Array<DoubleArray>.
This is more efficient because Array<Double> boxes the numbers
inside it, whereas DoubleArray is unboxed.
