fixed_wide_vectors/fixed_wide/src/tests.rs

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use crate::types::I32F32;
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#[test]
fn test_wide_mul(){
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let a=I32F32::ONE;
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let aa=a.wide_mul(a);
assert_eq!(aa,crate::types::I64F64::ONE);
}
#[test]
fn test_bint(){
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let a=I32F32::ONE;
assert_eq!(a*2,I32F32::from(2));
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}
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#[test]
fn test_sqrt(){
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let a=I32F32::ONE*4;
assert_eq!(a.sqrt(),I32F32::from(2));
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}
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#[test]
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fn test_sqrt_zero(){
let a=I32F32::ZERO;
assert_eq!(a.sqrt(),I32F32::ZERO);
}
#[test]
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fn test_sqrt_low(){
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let a=I32F32::HALF;
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let b=a*a;
assert_eq!(b.sqrt(),a);
}
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fn find_equiv_sqrt_via_f64(n:I32F32)->I32F32{
//GIMME THEM BITS BOY
let &[bits]=n.to_bits().to_bits().digits();
let ibits=bits as i64;
let f=(ibits as f64)/((1u64<<32) as f64);
let f_ans=f.sqrt();
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let i=(f_ans*((1u64<<32) as f64)) as i64;
let r=I32F32::from_bits(bnum::BInt::<1>::from(i));
//mimic the behaviour of the algorithm,
//return the result if it truncates to the exact answer
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if (r+I32F32::EPSILON).wide_mul(r+I32F32::EPSILON)==n.wide_mul(I32F32::ONE){
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return r+I32F32::EPSILON;
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}
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if (r-I32F32::EPSILON).wide_mul(r-I32F32::EPSILON)==n.wide_mul(I32F32::ONE){
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return r-I32F32::EPSILON;
}
return r;
}
fn test_exact(n:I32F32){
assert_eq!(n.sqrt(),find_equiv_sqrt_via_f64(n));
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}
#[test]
fn test_sqrt_exact(){
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//43
for i in 0..((i64::MAX as f32).ln() as u32){
let n=I32F32::from_bits(bnum::BInt::<1>::from((i as f32).exp() as i64));
test_exact(n);
}
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}
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#[test]
fn test_sqrt_max(){
let a=I32F32::MAX;
test_exact(a);
}