nlpodyssey/spago

// Copyright 2022 The NLP Odyssey Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

//go:build amd64 && gc && !purego

package matfuncs

import "math"

// Log32 computes the natural logarithm of each element of x, storing the result in y (32 bits).
func Log32(x, y []float32) {
    if len(x) == 0 {
        return
    }

    if hasAVX2 {
        _ = y[len(x)-1]
        max := len(x) - 8
        for i := 0; i <= max; i += 8 {
            LogAVX32(x[i:], y[i:])
        }

        if max > 0 {
            for i, v := range x[:max+1] {
                if v == 0.0 {
                    y[i] = float32(math.Inf(-1))
                }
            }
        }

        mod := len(x) % 8
        if mod > 0 {
            tailStart := len(x) - mod
            log(x[tailStart:], y[tailStart:])
        }
        return
    }

    _ = y[len(x)-1]
    max := len(x) - 4
    for i := 0; i <= max; i += 4 {
        LogSSE32(x[i:], y[i:])
    }

    if max > 0 {
        for i, v := range x[:max+1] {
            if v == 0.0 {
                y[i] = float32(math.Inf(-1))
            }
        }
    }

    mod := len(x) % 4
    if mod > 0 {
        tailStart := len(x) - mod
        log(x[tailStart:], y[tailStart:])
    }
}

// Log64 computes the natural logarithm of each element of x, storing the result in y (64 bits).
func Log64(x, y []float64) {
    log(x, y)
}