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smarter sqrt

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Quaternions 2024-08-29 12:12:14 -07:00
parent 3d3eb966a4
commit 8ba76c7a00
1 changed files with 10 additions and 18 deletions
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28
fixed_wide/src/fixed.rs
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@ -289,25 +289,17 @@ impl<const CHUNKS:usize,Frac:Unsigned> Fixed<CHUNKS,Frac>
Fixed::<CHUNKS,Frac>:std::ops::Mul<Fixed<CHUNKS,Frac>,Output=Fixed<CHUNKS,Frac>>, Fixed::<CHUNKS,Frac>:std::ops::Mul<Fixed<CHUNKS,Frac>,Output=Fixed<CHUNKS,Frac>>,
{ {
pub fn sqrt_unchecked(self)->Self{ pub fn sqrt_unchecked(self)->Self{
//find pow2 more powerful than self //pow2 must be the minimum power of two which when squared is greater than self
let mut pow2=if Self::ONE<self{ //0001.0000 Fixed<u8,4>
let mut pow2=Self::TWO;//1<self is so bake one iteration //sqrt
while pow2<=self{ //0110.0000
pow2<<=1; //pow2 = 0100.0000
} let mut pow2=Self{
pow2 bits:BInt::<CHUNKS>::ONE.shl((((CHUNKS as i32*64-Frac::I32-(self.bits.leading_zeros() as i32)+1)>>1)+Frac::I32) as u32),
}else if Self::ONE==self{ frac:PhantomData,
return Self::ONE;
}else if Self::ZERO<self{
let mut pow2=Self::ONE;
while self<=pow2{
pow2>>=1;
}
pow2
}else{//either 0==self or self is negative
return Self::ZERO;
}; };
let mut result=pow2; let mut result=pow2>>1;
while pow2!=Self::ZERO{ while pow2!=Self::ZERO{
pow2>>=1; pow2>>=1;
let new_result=result+pow2; let new_result=result+pow2;