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Use i64 for lunation number #75

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Use i64 for lunation number #75

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6 changes: 3 additions & 3 deletions src/ephemeris.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -31,9 +31,9 @@ pub fn get_ephemeris(timestamp: i64, longitude: f64, latitude: f64) -> BTreeMap<
let n = get_lunation_number(day_begin_at); // FIXME: Potential bug here
let es = vec![
("New Moon", get_new_moon(n)),
("First Quarter Moon", get_first_quarter_moon(n + 0.25)),
("Full Moon", get_full_moon(n + 0.50)),
("Last Quarter Moon", get_last_quarter_moon(n + 0.75))
("First Quarter Moon", get_first_quarter_moon(n)),
("Full Moon", get_full_moon(n)),
("Last Quarter Moon", get_last_quarter_moon(n))
];
for (name, e) in es {
if day_begin_at < e && e < day_end_at {
Expand Down
55 changes: 25 additions & 30 deletions src/moon_phase.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -17,18 +17,13 @@ enum MoonPhase {

// From "Astronomical Algorithms"
// By Jean Meeus
fn get_time_of(phase: MoonPhase, lunation_number: f64) -> i64 {
/*
// TODO: use `lunation_number: i64`
fn get_time_of(phase: MoonPhase, lunation_number: i64) -> i64 {
let k = match phase {
MoonPhase::NewMoon => (lunation_number as f64) + 0.00;
MoonPhase::FirstQuarterMoon => (lunation_number as f64) + 0.25;
MoonPhase::FullMoon => (lunation_number as f64) + 0.50;
MoonPhase::LastQuarterMoon => (lunation_number as f64) + 0.75;
MoonPhase::NewMoon => (lunation_number as f64) + 0.00,
MoonPhase::FirstQuarterMoon => (lunation_number as f64) + 0.25,
MoonPhase::FullMoon => (lunation_number as f64) + 0.50,
MoonPhase::LastQuarterMoon => (lunation_number as f64) + 0.75,
};
*/

let k = lunation_number;
let t = k / 1236.85;

let e = 1.0 - 0.002_516 * t - 0.000_007_4 * t.powi(2);
Expand Down Expand Up @@ -211,19 +206,19 @@ fn get_time_of(phase: MoonPhase, lunation_number: f64) -> i64 {
terrestrial_to_universal_time(julian_to_unix(jde))
}

pub fn get_new_moon(lunation_number: f64) -> i64 {
pub fn get_new_moon(lunation_number: i64) -> i64 {
get_time_of(MoonPhase::NewMoon, lunation_number)
}

pub fn get_first_quarter_moon(lunation_number: f64) -> i64 {
pub fn get_first_quarter_moon(lunation_number: i64) -> i64 {
get_time_of(MoonPhase::FirstQuarterMoon, lunation_number)
}

pub fn get_full_moon(lunation_number: f64) -> i64 {
pub fn get_full_moon(lunation_number: i64) -> i64 {
get_time_of(MoonPhase::FullMoon, lunation_number)
}

pub fn get_last_quarter_moon(lunation_number: f64) -> i64 {
pub fn get_last_quarter_moon(lunation_number: i64) -> i64 {
get_time_of(MoonPhase::LastQuarterMoon, lunation_number)
}

Expand All @@ -239,16 +234,16 @@ enum LunationNumbering {
*/

/// Computes the Lunation Number since the first new moon of 2000
pub fn get_lunation_number(timestamp: i64) -> f64 {
((unix_to_year(timestamp) - 2000.0) * 12.3685).floor() // TODO: `as i64`
pub fn get_lunation_number(timestamp: i64) -> i64 {
((unix_to_year(timestamp) - 2000.0) * 12.3685).floor() as i64
}

pub fn get_next_new_moon(timestamp: i64) -> i64 {
let new_moon = get_new_moon(get_lunation_number(timestamp));
if new_moon > timestamp {
new_moon
} else {
get_new_moon(get_lunation_number(timestamp) + 1.0)
get_new_moon(get_lunation_number(timestamp) + 1)
}
}

Expand All @@ -262,63 +257,63 @@ mod tests {
// Example 49.a from "Astronomical Algoritms"
// New Moon: 1977-02-18 03:37:42 TD
let t = terrestrial_to_universal_time(parse_time("1977-02-18T03:37:42.00+00:00"));
assert_eq!(-283.0, get_lunation_number(t));
assert_eq!(-283, get_lunation_number(t));

// Later in the day
let t = parse_time("1977-02-18T12:00:00.00+00:00");
assert_eq!(-283.0, get_lunation_number(t));
assert_eq!(-283, get_lunation_number(t));

// Later in the month
let t = parse_time("1977-02-28T12:00:00.00+00:00");
assert_eq!(-283.0, get_lunation_number(t));
assert_eq!(-283, get_lunation_number(t));

// Earlier in the day
let t = parse_time("1977-02-18T01:00:00.00+00:00");
assert_eq!(-283.0, get_lunation_number(t));
assert_eq!(-283, get_lunation_number(t));

// A few days before
let t = parse_time("1977-02-14T12:00:00.00+00:00");
assert_eq!(-283.0, get_lunation_number(t)); // FIXME: should be -284
assert_eq!(-283, get_lunation_number(t)); // FIXME: should be -284

// A week before
let t = parse_time("1977-02-11T12:00:00.00+00:00");
assert_eq!(-284.0, get_lunation_number(t));
assert_eq!(-284, get_lunation_number(t));

// Meeus Lunation 0
let t = parse_time("2000-01-06T18:14:00.00+00:00");
assert_eq!(0.0, get_lunation_number(t));
assert_eq!(0, get_lunation_number(t));

// Brown Lunation 1
let t = parse_time("1923-01-17T02:41:00.00+00:00");
assert_eq!(-952.0, get_lunation_number(t));
assert_eq!(-952, get_lunation_number(t));

// Islamic Lunation 1
let t = parse_time("0622-07-16T00:00:00.00+00:00");
assert_eq!(-17037.0, get_lunation_number(t));
assert_eq!(-17037, get_lunation_number(t));

// Thai Lunation 0
let t = parse_time("0638-03-22T00:00:00.00+00:00");
assert_eq!(-16843.0, get_lunation_number(t)); // FIXME: should be -16842
assert_eq!(-16843, get_lunation_number(t)); // FIXME: should be -16842
}

#[test]
fn get_new_moon_test() {
// Example 49.a from "Astronomical Algoritms"
// New Moon: 1977-02-18 03:37:42 TD
let lunation_number = -283.0;
let lunation_number = -283;
let t = terrestrial_to_universal_time(parse_time("1977-02-18T03:37:42.00+00:00"));
assert_eq!(t, get_new_moon(lunation_number));

// First new moon of 1970
let t = parse_time("1970-01-07T20:35:27.00+00:00");
assert_eq!(t, get_new_moon(get_lunation_number(0) + 1.0));
assert_eq!(t, get_new_moon(get_lunation_number(0) + 1));
}

#[test]
fn get_last_quarter_moon_test() {
// Example 49.b from "Astronomical Algoritms"
// Last Quarter Moon: 2044-01-21 23:48:17 TD
let lunation_number = 544.75;
let lunation_number = 544;
let t = terrestrial_to_universal_time(parse_time("2044-01-21T23:48:17+00:00"));
assert_eq!(t, get_last_quarter_moon(lunation_number));
}
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