Commit 8312383ffa0ea0290f2911fcba0aa3b62f5046bf
1 parent
c99cc1ee
continuous sqrt now uses a slice internally
Showing
1 changed file
with
7 additions
and
12 deletions
... | ... | @@ -31,28 +31,23 @@ impl Continuous { |
31 | 31 | // https://en.wikipedia.org/wiki/Methods_of_computing_square_roots# |
32 | 32 | // Continued_fraction_expansion |
33 | 33 | pub fn sqrt(x :i64, a0 :i64) -> Self { |
34 | - fn inner(mut v :Vec<i64>, | |
35 | - x :i64, | |
36 | - a0 :i64, | |
37 | - mn :i64, | |
38 | - dn :i64, | |
39 | - an :i64) -> Vec<i64> { | |
34 | + fn inner(v :&mut [i64], x :i64, a0 :i64, mn :i64, dn :i64, an :i64) { | |
40 | 35 | let mn_1 = dn * an - mn; |
41 | 36 | let dn_1 = (x - mn_1 * mn_1) / dn; |
42 | 37 | let an_1 = (a0 + mn_1) / dn_1; |
43 | 38 | |
44 | - v.push(an); | |
45 | - | |
39 | + v[0] = an; | |
46 | 40 | // The convergence criteria „an_1 == 2 * a0“ is not good for |
47 | 41 | // very small x thus I decided to break the iteration at constant |
48 | 42 | // time. Which is the 10 below. |
49 | - match v.len() { | |
50 | - 10 => v, | |
51 | - _ => inner(v, x, a0, mn_1, dn_1, an_1), | |
43 | + if v.len() > 1 { | |
44 | + inner(&mut v[1..], x, a0, mn_1, dn_1, an_1); | |
52 | 45 | } |
53 | 46 | } |
54 | 47 | |
55 | - Continuous(inner(Vec::new(), x, a0, 0, 1, a0)) | |
48 | + let mut v :Vec<i64> = vec!(0; 10); | |
49 | + inner(&mut v, x, a0, 0, 1, a0); | |
50 | + Continuous(v) | |
56 | 51 | } |
57 | 52 | } |
58 | 53 | ... | ... |
Please
register
or
login
to post a comment