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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.
15 lines
531 B
Rust
15 lines
531 B
Rust
use super::expf;
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/* k is such that k*ln2 has minimal relative error and x - kln2 > log(FLT_MIN) */
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const K: i32 = 235;
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/* expf(x)/2 for x >= log(FLT_MAX), slightly better than 0.5f*expf(x/2)*expf(x/2) */
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#[cfg_attr(assert_no_panic, no_panic::no_panic)]
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pub(crate) fn k_expo2f(x: f32) -> f32 {
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let k_ln2 = f32::from_bits(0x4322e3bc);
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/* note that k is odd and scale*scale overflows */
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let scale = f32::from_bits(((0x7f + K / 2) as u32) << 23);
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/* exp(x - k ln2) * 2**(k-1) */
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expf(x - k_ln2) * scale * scale
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}
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