40 lines
1.1 KiB
Rust
40 lines
1.1 KiB
Rust
extern crate alga;
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extern crate nalgebra as na;
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use alga::linear::Transformation;
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use na::{Id, Isometry3, Point3, Vector3};
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/*
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* Applies `n` times the transformation `t` to the vector `v` and sum each
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* intermediate value.
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*/
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fn complicated_algorithm<T>(v: &Vector3<f32>, t: &T, n: usize) -> Vector3<f32>
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where T: Transformation<Point3<f32>> {
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let mut result = *v;
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// Do lots of operations involving t.
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for _ in 0..n {
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result = v + t.transform_vector(&result);
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}
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result
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}
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/*
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* The two following calls are equivalent in term of result.
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*/
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fn main() {
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let v = Vector3::new(1.0, 2.0, 3.0);
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// The specialization generated by the compiler will do vector additions only.
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let result1 = complicated_algorithm(&v, &Id::new(), 100000);
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// The specialization generated by the compiler will also include matrix multiplications.
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let iso = Isometry3::identity();
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let result2 = complicated_algorithm(&v, &iso, 100000);
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// They both return the same result.
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assert!(result1 == Vector3::new(100001.0, 200002.0, 300003.0));
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assert!(result2 == Vector3::new(100001.0, 200002.0, 300003.0));
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}
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