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Reasonable convergence function
This commit is contained in:
Denis Redozubov
parent
081188e80a
commit
e843a98876
1 changed files with 44 additions and 145 deletions
189
src/midi/time.rs
189
src/midi/time.rs
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@ -1,5 +1,5 @@
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extern crate derive_more;
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use crate::dsl::dsl::{BasicLength, KnownLength, Group, GroupOrNote, Note, FOURTH, Times, EIGHTH};
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use crate::dsl::dsl::{BasicLength, Group, GroupOrNote, KnownLength, Note, Times, EIGHTH, FOURTH};
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use std::cmp::Ordering;
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use std;
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@ -56,172 +56,71 @@ impl KnownLength for TimeSignature {
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}
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impl TimeSignature {
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fn converges_with(&self, other: TimeSignature) -> Result<(u32, TimeSignature), String> {
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let d: u32 = std::cmp::max(self.denominator, other.denominator)
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.to_note_length()
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.into();
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let d1: u32 = self.denominator.to_note_length().into();
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let d2: u32 = other.denominator.to_note_length().into();
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let coef1 = d / d1;
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let coef2 = d / d2;
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let num1: u32 = coef1 * (self.numerator as u32);
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let num2: u32 = coef2 * (other.numerator as u32);
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let greater_time_signature = self.max(&other);
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let f = |max, min| {
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let mut res = Err(format!("Not converges over 1000 bars of {:?}", other));
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for i in 1..1000 {
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if (max * i) % min == 0 {
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res = Ok((i, *greater_time_signature));
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break;
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}
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}
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res
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};
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match num1.cmp(&num2) {
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std::cmp::Ordering::Less => f(num2, num1),
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std::cmp::Ordering::Equal => Ok((1, *greater_time_signature)),
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std::cmp::Ordering::Greater => f(num1, num2),
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}
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}
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/// The function takes a vector of time signatures and tries to find out if they all converge over a finite number of bars.
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///
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/// Arguments:
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///
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/// * `time_signatures`: `time_signatures` is a vector of `TimeSignature` structs. The function
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/// `converges` takes this vector as input and iterates over it using the `iter()` method. It then
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/// uses the `try_fold()` method to fold over the vector and accumulate a result.
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///
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/// Returns:
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///
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/// Returns the number of bars to converge + suggested time signature.
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/// Returns Err if signatures won't converge.
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fn converges(
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&self,
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time_signatures: Vec<TimeSignature>,
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) -> Result<(u32, TimeSignature), String> {
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time_signatures
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.iter()
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.try_fold((1, *self), |(bars, ts), x| match ts.converges_with(*x) {
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Ok((new_bars, greater_signature)) => {
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if new_bars > bars {
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if new_bars % bars == 0 {
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Ok((new_bars, greater_signature))
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} else {
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Err(format!("{:?} don't converge with {:?}", self, x))
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}
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} else {
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if bars % new_bars == 0 {
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Ok((bars, greater_signature))
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} else {
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Err(format!("{:?} don't converge with {:?}", self, x))
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}
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}
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}
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Err(e) => Err(e),
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})
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}
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/// Returns number of bars in the specified time signature that it takes to converge with the group.
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/// Otherwise returns Err.
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fn converges_over<T: KnownLength>(&self, over: T) -> Result<u32, String> {
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pub fn converges<T: KnownLength>(&self, multiple: Vec<T>) -> Result<u32, String> {
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let bar_len = self.to_128th();
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let mut bars = 1;
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let group_len = over.to_128th();
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let mut out = Err("Do not converge".to_string());
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let result = multiple
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.iter()
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.fold(bar_len, |acc, t| lowest_common_divisor(t.to_128th(), acc));
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let limit = 1000;
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while bars <= limit {
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let bars_len = bar_len * bars;
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if bars_len % group_len == 0 {
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// return
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out = Ok(bars);
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break
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}
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let out = result / bar_len;
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if bars == limit {
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break;
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} else {
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bars += 1
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}
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if limit > out {
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Ok(out)
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} else {
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Err("Does not converge".to_string())
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}
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out
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}
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}
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#[test]
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fn test_converges_over() {
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let four_fourth = TimeSignature {
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numerator: 4,
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denominator: BasicLength::Fourth,
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};
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let three_fourth_group = Group {
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notes: vec![GroupOrNote::SingleNote(Note::Hit)],
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length: FOURTH.clone(),
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times: Times(3)
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};
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let thirteen_eights = Group {
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notes: vec![GroupOrNote::SingleNote(Note::Hit)],
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length: FOURTH.clone(),
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times: Times(12)
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};
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let in_shards_poly = Group {
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notes: vec![GroupOrNote::SingleNote(Note::Hit), GroupOrNote::SingleNote(Note::Rest), GroupOrNote::SingleGroup(thirteen_eights)],
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length: EIGHTH.clone(),
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times: Times(1)
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};
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assert_eq!(four_fourth.converges_over(three_fourth_group), Ok(3));
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assert_eq!(four_fourth.converges_over(in_shards_poly), Ok(13));
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fn lowest_common_divisor(a: u32, b: u32) -> u32 {
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let mut lcm = u32::max(a, b);
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while lcm % a != 0 || lcm % b != 0 {
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lcm += 1;
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}
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lcm
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}
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#[test]
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fn test_converges_with() {
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let three_sixteenth = TimeSignature {
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numerator: 3,
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denominator: BasicLength::Sixteenth,
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};
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let four_fourth = TimeSignature {
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numerator: 4,
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denominator: BasicLength::Fourth,
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};
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let thirteen_eights = TimeSignature {
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numerator: 13,
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denominator: BasicLength::Eighth,
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};
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assert_eq!(
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three_sixteenth.converges_with(four_fourth),
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Ok((3, four_fourth))
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);
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assert_eq!(
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thirteen_eights.converges_with(four_fourth),
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Ok((15, four_fourth))
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)
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fn test_lcm() {
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assert_eq!(lowest_common_divisor(128, 96), 384);
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assert_eq!(lowest_common_divisor(96, 128), 384);
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}
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#[test]
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fn test_converges() {
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let three_sixteenth = TimeSignature {
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numerator: 3,
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denominator: BasicLength::Sixteenth,
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};
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let four_fourth = TimeSignature {
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numerator: 4,
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denominator: BasicLength::Fourth,
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};
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let six_fourth = TimeSignature {
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numerator: 6,
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denominator: BasicLength::Fourth,
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};
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let three_fourth = TimeSignature {
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numerator: 3,
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denominator: BasicLength::Fourth,
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};
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let thirteen_eights = TimeSignature {
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numerator: 13,
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denominator: BasicLength::Eighth,
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let thirteen_eights = Group {
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notes: vec![GroupOrNote::SingleNote(Note::Hit)],
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length: FOURTH.clone(),
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times: Times(12),
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};
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assert_eq!(
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three_sixteenth.converges(vec![four_fourth, three_fourth, four_fourth]),
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Ok((3, four_fourth))
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);
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assert_eq!(
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four_fourth.converges(vec![thirteen_eights]),
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Ok((15, four_fourth))
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);
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let in_shards_poly = Group {
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notes: vec![
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GroupOrNote::SingleNote(Note::Hit),
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GroupOrNote::SingleNote(Note::Rest),
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GroupOrNote::SingleGroup(thirteen_eights),
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],
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length: EIGHTH.clone(),
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times: Times(1),
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};
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assert_eq!(three_fourth.converges(vec![four_fourth]), Ok(4));
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assert_eq!(four_fourth.converges(vec![three_fourth]), Ok(3));
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assert_eq!(four_fourth.converges(vec![three_fourth, four_fourth]), Ok(3));
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assert_eq!(four_fourth.converges(vec![three_fourth, six_fourth, four_fourth]), Ok(3));
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assert_eq!(four_fourth.converges(vec![in_shards_poly]), Ok(13));
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}
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