Math.log2

(::Math::double x) -> ::Float

Math.log2(x) → float

static VALUE
math_log2(VALUE unused_obj, VALUE x)
{
    size_t numbits;
    double d = get_double_rshift(x, &numbits);

    domain_check_min(d, 0.0, "log2");
    /* check for pole error */
    if (d == 0.0) return DBL2NUM(-HUGE_VAL);

    return DBL2NUM(log2(d) + numbits); /* log2(d * 2 ** numbits) */
}

Returns the base 2 logarithm of x.

Domain: [0, INFINITY].
Range: [-INFINITY, INFINITY].

Examples:

Example

log2(0.0)      # => -Infinity
log2(1.0)      # => 0.0
log2(2.0)      # => 1.0
log2(INFINITY) # => Infinity

See also .log10 .sin .log .sinh also in 4.1 · 4.0 · 3.3 · 3.2 · 3.1 · 3.0

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