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ecf6d3c6ce
Currently, attributes for `no-panic` are gated behind both the `test` config and `assert_no_panic`, because `no-panic` is a dev dependency (so only available with test configuration). However, we only emit `assert_no_panic` when the test config is also set anyway, so there isn't any need to gate on both. Replace gates on `all(test, assert_no_panic)` with only `assert_no_panic`. This is simpler, and also has the benefit that attempting to check for panics without `--test` errors.
27 lines
812 B
Rust
27 lines
812 B
Rust
use super::{log1pf, logf, sqrtf};
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const LN2: f32 = 0.693147180559945309417232121458176568;
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/// Inverse hyperbolic cosine (f32)
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///
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/// Calculates the inverse hyperbolic cosine of `x`.
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/// Is defined as `log(x + sqrt(x*x-1))`.
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/// `x` must be a number greater than or equal to 1.
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#[cfg_attr(assert_no_panic, no_panic::no_panic)]
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pub fn acoshf(x: f32) -> f32 {
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let u = x.to_bits();
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let a = u & 0x7fffffff;
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if a < 0x3f800000 + (1 << 23) {
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/* |x| < 2, invalid if x < 1 or nan */
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/* up to 2ulp error in [1,1.125] */
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return log1pf(x - 1.0 + sqrtf((x - 1.0) * (x - 1.0) + 2.0 * (x - 1.0)));
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}
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if a < 0x3f800000 + (12 << 23) {
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/* |x| < 0x1p12 */
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return logf(2.0 * x - 1.0 / (x + sqrtf(x * x - 1.0)));
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}
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/* x >= 0x1p12 */
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return logf(x) + LN2;
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}
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