blob: f1bb4be7e78124f8cfc9e13edd59794238837f63 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
|
const std = @import("../std.zig");
const math = std.math;
const expect = std.testing.expect;
/// Returns the absolute value of x.
///
/// Special Cases:
/// - fabs(+-inf) = +inf
/// - fabs(nan) = nan
pub fn fabs(x: anytype) @TypeOf(x) {
const T = @TypeOf(x);
const TBits = std.meta.Int(.unsigned, @bitSizeOf(T));
if (@typeInfo(T) != .Float) {
@compileError("fabs not implemented for " ++ @typeName(T));
}
const float_bits = @bitCast(TBits, x);
const remove_sign = ~@as(TBits, 0) >> 1;
return @bitCast(T, float_bits & remove_sign);
}
test "math.fabs" {
// TODO add support for f80 & c_longdouble here
inline for ([_]type{ f16, f32, f64, f128 }) |T| {
// normals
try expect(fabs(@as(T, 1.0)) == 1.0);
try expect(fabs(@as(T, -1.0)) == 1.0);
try expect(fabs(math.floatMin(T)) == math.floatMin(T));
try expect(fabs(-math.floatMin(T)) == math.floatMin(T));
try expect(fabs(math.floatMax(T)) == math.floatMax(T));
try expect(fabs(-math.floatMax(T)) == math.floatMax(T));
// subnormals
try expect(fabs(@as(T, 0.0)) == 0.0);
try expect(fabs(@as(T, -0.0)) == 0.0);
try expect(fabs(math.floatTrueMin(T)) == math.floatTrueMin(T));
try expect(fabs(-math.floatTrueMin(T)) == math.floatTrueMin(T));
// non-finite numbers
try expect(math.isPositiveInf(fabs(math.inf(T))));
try expect(math.isPositiveInf(fabs(-math.inf(T))));
try expect(math.isNan(fabs(math.nan(T))));
}
}
|
