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math: add round_sig function for f64 (#14997)

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CC 2022-07-09 01:41:58 -06:00 committed by GitHub
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commit 7e1c45ab44
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29
vlib/math/floor.v
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@ -75,6 +75,35 @@ pub fn round(x f64) f64 {
return y return y
} }
// Returns the rounded float, with sig_digits of precision.
// i.e `assert round_sig(4.3239437319748394,6) == 4.323944`
pub fn round_sig(x f64, sig_digits int) f64 {
mut ret_str := '$x'
match sig_digits {
0 { ret_str = '${x:0.0f}' }
1 { ret_str = '${x:0.1f}' }
2 { ret_str = '${x:0.2f}' }
3 { ret_str = '${x:0.3f}' }
4 { ret_str = '${x:0.4f}' }
5 { ret_str = '${x:0.5f}' }
6 { ret_str = '${x:0.6f}' }
7 { ret_str = '${x:0.7f}' }
8 { ret_str = '${x:0.8f}' }
9 { ret_str = '${x:0.9f}' }
10 { ret_str = '${x:0.10f}' }
11 { ret_str = '${x:0.11f}' }
12 { ret_str = '${x:0.12f}' }
13 { ret_str = '${x:0.13f}' }
14 { ret_str = '${x:0.14f}' }
15 { ret_str = '${x:0.15f}' }
16 { ret_str = '${x:0.16f}' }
else { ret_str = '$x' }
}
return ret_str.f64()
}
// round_to_even returns the nearest integer, rounding ties to even. // round_to_even returns the nearest integer, rounding ties to even.
// //
// special cases are: // special cases are:

11
vlib/math/math_test.v
View File

@ -808,6 +808,17 @@ fn test_round() {
} }
} }
fn fn_test_round_sig() {
assert round_sig(4.3239437319748394, -1) == 4.3239437319748394
assert round_sig(4.3239437319748394, 0) == 4.0000000000000000
assert round_sig(4.3239437319748394, 1) == 4.3000000000000000
assert round_sig(4.3239437319748394, 2) == 4.3200000000000000
assert round_sig(4.3239437319748394, 3) == 4.3240000000000000
assert round_sig(4.3239437319748394, 6) == 4.3239440000000000
assert round_sig(4.3239437319748394, 12) == 4.323943731975
assert round_sig(4.3239437319748394, 17) == 4.3239437319748394
}
fn test_sin() { fn test_sin() {
for i := 0; i < math.vf_.len; i++ { for i := 0; i < math.vf_.len; i++ {
f := sin(math.vf_[i]) f := sin(math.vf_[i])