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Add approxEqAbs support for comptime_float

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Eric Eastwood 2024-01-06 04:36:47 -06:00 committed by Andrew Kelley
parent faeb0ef032
commit 2115d7d1be
1 changed files with 20 additions and 2 deletions
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22
lib/std/math.zig
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@ -120,7 +120,7 @@ pub const epsilon = @compileError("Deprecated: use `floatEps` instead");
///
/// NaN values are never considered equal to any value.
pub fn approxEqAbs(comptime T: type, x: T, y: T, tolerance: T) bool {
assert(@typeInfo(T) == .Float);
assert(@typeInfo(T) == .Float or @typeInfo(T) == .ComptimeFloat);
assert(tolerance >= 0);
// Fast path for equal values (and signed zeros and infinites).
@ -148,7 +148,7 @@ pub fn approxEqAbs(comptime T: type, x: T, y: T, tolerance: T) bool {
///
/// NaN values are never considered equal to any value.
pub fn approxEqRel(comptime T: type, x: T, y: T, tolerance: T) bool {
assert(@typeInfo(T) == .Float);
assert(@typeInfo(T) == .Float or @typeInfo(T) == .ComptimeFloat);
assert(tolerance > 0);
// Fast path for equal values (and signed zeros and infinites).
@ -184,6 +184,24 @@ test "approxEqAbs and approxEqRel" {
try testing.expect(approxEqAbs(T, min_value, 0.0, eps_value * 2));
try testing.expect(approxEqAbs(T, -min_value, 0.0, eps_value * 2));
}
comptime {
// `comptime_float` is guaranteed to have the same precision and operations of
// the largest other floating point type, which is f128 but it doesn't have a
// defined layout so we can't rely on `@bitCast` to construct the smallest
// possible epsilon value like we do in the tests above. In the same vein, we
// also can't represent a max/min, `NaN` or `Inf` values.
const eps_value = 1e-4;
const sqrt_eps_value = sqrt(eps_value);
try testing.expect(approxEqAbs(comptime_float, 0.0, 0.0, eps_value));
try testing.expect(approxEqAbs(comptime_float, -0.0, -0.0, eps_value));
try testing.expect(approxEqAbs(comptime_float, 0.0, -0.0, eps_value));
try testing.expect(approxEqRel(comptime_float, 1.0, 1.0, sqrt_eps_value));
try testing.expect(!approxEqRel(comptime_float, 1.0, 0.0, sqrt_eps_value));
try testing.expect(!approxEqAbs(comptime_float, 1.0 + 2 * eps_value, 1.0, eps_value));
try testing.expect(approxEqAbs(comptime_float, 1.0 + 1 * eps_value, 1.0, eps_value));
}
}
pub const doNotOptimizeAway = @compileError("Deprecated: use `std.mem.doNotOptimizeAway` instead");