This crate is useful when you need to work with algorithms like
Dijkstra's Shortest Path or
Floyd–Warshall algorithm
that require infinite values in order to be written elegantly.
One simple example can be finding the max value in a vector:
use magnitude::Magnitude;
fn find_max(vec: &Vec<Magnitude<i32>>) -> Magnitude<i32> {
let mut max = Magnitude::NegInfinite;
for val in vec {
if *val > max {
max = *val;
}
}
max
}
let vec: Vec<Magnitude<i32>> = vec![2.into(), 3.into(), 6.into(), (-10).into()];
assert_eq!(find_max(&vec), 6.into());
You can do all valid comparison(==, !=, >, <, >=, <=) and arithmetic(+,-, *, /, +=, -=, *=, /=) operations on magnitudes.
Invalid operations are listed below which means any other operation is valid.
- Comparison:
- two
PosInfinite
- two
NegInfinite
- two
- Arithmetic:
- Add:
PosInfinite
+NegInfinite
- Sub:
PosInfinite
-PosInfinite
NegInfinite
-NegInfinite
- Mul:
- zero *
PosInfinite
- zero *
NegInfinite
- zero *
- Div:
- non-zero /
PosInfinite
- non-zero /
NegInfinite
PosInfinite
/ zeroNegInfinite
/ zeroPosInfinite
/PosInfinite
PosInfinite
/NegInfinite
NegInfinite
/PosInfinite
NegInfinite
/NegInfinite
- non-zero /
- Add:
Magnitude as of 0.2.0 treat f64::INFINITY
, f64::NEG_INFINITY
, f32::INFINITY
, f32::NEG_INFINITY
as infinites:
use magnitude::Magnitude;
let pos_inf: Magnitude<f64> = f64::INFINITY.into();
let neg_inf: Magnitude<f64> = f64::NEG_INFINITY.into();
assert!(pos_inf.is_pos_infinite());
assert!(neg_inf.is_neg_infinite());
let pos_inf: Magnitude<f32> = f32::INFINITY.into();
let neg_inf: Magnitude<f32> = f32::NEG_INFINITY.into();
assert!(pos_inf.is_pos_infinite());
assert!(neg_inf.is_neg_infinite());
- 0.3.2: Enforce
Copy
instead ofClone
. - 0.3.1: Fixed is_finite() bug.
- 0.3.0:
- add
from_vec
to build a vector ofMagnitude
from a vector of values:use magnitude::Magnitude; let magnitude_vec = Magnitude::from_vec(&vec![1,2,3]); assert_eq!(magnitude_vec[0], 1.into()); assert_eq!(magnitude_vec[1], 2.into()); assert_eq!(magnitude_vec[2], 3.into());
- add
unwrap
for easier access to value insideFinite
:use magnitude::Magnitude; let one: Magnitude<i32> = 1.into(); assert_eq!(one.unwrap(), 1);
- add
- 0.2.0: handle
f64::INFINITY
,f64::NEG_INFINITY
,f32::INFINITY
,f32::NEG_INFINITY
properly
special thanks to @niklasmohrin and @smarnach