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primitive_float_asin_rational

Function primitive_float_asin_rational 

Source
pub fn primitive_float_asin_rational<T>(x: &Rational) -> T
where Float: PartialOrd<T>, for<'a> T: ExactFrom<&'a Float> + PrimitiveFloat,
Expand description

Computes $\arcsin x$, the arcsine of a Rational, returning the result as a primitive float.

$$ f(x) = \arcsin x+\varepsilon, $$ where $|\varepsilon| < 2^{\lfloor\log_2 |\arcsin x|\rfloor-p}$ and $p$ is the precision of the output (24 if T is a f32 and 53 if T is a f64); the special cases below are exact.

Special cases:

  • $f(x)=\text{NaN}$ for $|x|>1$
  • $f(0)=0.0$
  • $f(\pm1)=\pm\pi/2$, rounded

Overflow is not possible, since the result lies in $[-\pi/2, \pi/2]$. The result is subnormal, or zero, only for an $x$ that is itself that small.

§Worst-case complexity

$T(m) = O(m \log m \log\log m)$

$M(m) = O(m \log m)$

where $T$ is time, $M$ is additional memory, and $m$ is x.significant_bits().

§Examples

use malachite_base::num::basic::traits::{One, Zero};
use malachite_base::num::float::NiceFloat;
use malachite_float::float::arithmetic::asin::primitive_float_asin_rational;
use malachite_q::Rational;

assert_eq!(
    NiceFloat(primitive_float_asin_rational::<f64>(&Rational::ZERO)),
    NiceFloat(0.0)
);
assert_eq!(
    NiceFloat(primitive_float_asin_rational::<f64>(&Rational::ONE)),
    NiceFloat(1.5707963267948966)
);
assert_eq!(
    NiceFloat(primitive_float_asin_rational::<f64>(
        &Rational::from_unsigneds(3u8, 5)
    )),
    NiceFloat(0.6435011087932844)
);
assert_eq!(
    NiceFloat(primitive_float_asin_rational::<f32>(
        &Rational::from_unsigneds(3u8, 5)
    )),
    NiceFloat(0.6435011)
);