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ruin zeroes

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Quaternions 2024-08-27 16:34:21 -07:00
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commit 3bb280a787
1 changed files with 37 additions and 31 deletions
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68
src/zeroes.rs
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@ -1,41 +1,47 @@
//find roots of polynomials
use arrayvec::ArrayVec;
use crate::integer::Planar64;
use std::cmp::Ordering;
use deferred_division::ratio::Ratio;
use fixed_wide::typenum::Unsigned;
use fixed_wide::fixed::Fixed;
use fixed_wide::wide::WideMul;
#[inline]
pub fn zeroes2(a0:Planar64,a1:Planar64,a2:Planar64)->ArrayVec<Planar64,2>{
if a2==Planar64::ZERO{
return zeroes1(a0,a1);
}
let radicand=a1.get() as i128*a1.get() as i128-a2.get() as i128*a0.get() as i128*4;
if 0<radicand{
//start with f64 sqrt
//failure case: 2^63 < sqrt(2^127)
let planar_radicand=Planar64::raw(unsafe{(radicand as f64).sqrt().to_int_unchecked()});
//TODO: one or two newtons
//sort roots ascending and avoid taking the difference of large numbers
match (Planar64::ZERO<a2,Planar64::ZERO<a1){
(true, true )=>[(-a1-planar_radicand)/(a2*2),(a0*2)/(-a1-planar_radicand)].into(),
(true, false)=>[(a0*2)/(-a1+planar_radicand),(-a1+planar_radicand)/(a2*2)].into(),
(false,true )=>[(a0*2)/(-a1-planar_radicand),(-a1-planar_radicand)/(a2*2)].into(),
(false,false)=>[(-a1+planar_radicand)/(a2*2),(a0*2)/(-a1+planar_radicand)].into(),
}
}else if radicand==0{
return ArrayVec::from_iter([a1/(a2*-2)]);
}else{
return ArrayVec::new_const();
pub fn zeroes2<const N:usize,F:Unsigned>(a0:Fixed<N,F>,a1:Fixed<N,F>,a2:Fixed<N,F>)->ArrayVec<Ratio<Fixed<N,F>,Fixed<N,F>>,2>
where
Fixed<N,F>:WideMul,
<Fixed<N,F> as WideMul>::Output:std::ops::Mul<i64>,
<Fixed<N,F> as WideMul>::Output:std::ops::Sub<<<Fixed<N,F> as WideMul>::Output as std::ops::Mul<i64>>::Output>
{
let a2pos=match a2.cmp(&Fixed::<N,F>::ZERO){
Ordering::Greater=>true,
Ordering::Equal=>return zeroes1(a0,a1),
Ordering::Less=>true,
};
let radicand=a1.wide_mul(a1)-a2.wide_mul(a0)*4;
match radicand.cmp(&Fixed::<N,F>::ZERO){
Ordering::Greater=>{
//start with f64 sqrt
//failure case: 2^63 < sqrt(2^127)
let planar_radicand=radicand.sqrt();
//TODO: one or two newtons
//sort roots ascending and avoid taking the difference of large numbers
match (a2pos,Fixed::<N,F>::ZERO<a1){
(true, true )=>[Ratio::new(-a1-planar_radicand,a2*2),Ratio::new(a0*2,-a1-planar_radicand)].into(),
(true, false)=>[Ratio::new(a0*2,-a1+planar_radicand),Ratio::new(-a1+planar_radicand,a2*2)].into(),
(false,true )=>[Ratio::new(a0*2,-a1-planar_radicand),Ratio::new(-a1-planar_radicand,a2*2)].into(),
(false,false)=>[Ratio::new(-a1+planar_radicand,a2*2),Ratio::new(a0*2,-a1+planar_radicand)].into(),
}
},
Ordering::Equal=>ArrayVec::from_iter([Ratio::new(a1,a2*-2)]),
Ordering::Less=>ArrayVec::new_const(),
}
}
#[inline]
pub fn zeroes1(a0:Planar64,a1:Planar64)->ArrayVec<Planar64,2>{
if a1==Planar64::ZERO{
return ArrayVec::new_const();
pub fn zeroes1<const N:usize,F:Unsigned>(a0:Fixed<N,F>,a1:Fixed<N,F>)->ArrayVec<Ratio<Fixed<N,F>,Fixed<N,F>>,2>{
if a1==Fixed::<N,F>::ZERO{
ArrayVec::new_const()
}else{
let q=((-a0.get() as i128)<<32)/(a1.get() as i128);
if i64::MIN as i128<=q&&q<=i64::MAX as i128{
return ArrayVec::from_iter([Planar64::raw(q as i64)]);
}else{
return ArrayVec::new_const();
}
ArrayVec::from_iter([Ratio::new(-a0,a1)])
}
}