sounio-benchmarks/083_pow_double.sio at main · Sounio-lang/sounio-benchmarks · GitHub

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//@ run-pass
// HumanEval 083: Power (Floating Point)
//
// Compute x^n for f64 base and i64 exponent using fast exponentiation
// (exponentiation by squaring). Handles negative exponents via 1/(x^|n|).
// O(log |n|) multiplications.

fn abs_i64(x: i64) -> i64 {
    if x < 0 { 0 - x } else { x }
}

fn abs_f64(x: f64) -> f64 {
    if x < 0.0 { 0.0 - x } else { x }
}

fn pow_double(x: f64, n: i64) -> f64 with Mut, Div, Panic {
    if n == 0 { return 1.0 }

    var base = x
    var exp = abs_i64(n)
    var result: f64 = 1.0

    while exp > 0 {
        if exp % 2 == 1 {
            result = result * base
        }
        base = base * base
        exp = exp / 2
    }

    if n < 0 {
        1.0 / result
    } else {
        result
    }
}

fn near(a: f64, b: f64, tol: f64) -> i64 {
    let d = a - b
    let ad = if d < 0.0 { 0.0 - d } else { d }
    if ad < tol { 1 } else { 0 }
}

fn main() -> i64 with IO, Mut, Panic, Div {
    // Test 1: 2.0^10 = 1024.0
    assert(near(pow_double(2.0, 10), 1024.0, 0.001) == 1)

    // Test 2: 2.0^0 = 1.0
    assert(near(pow_double(2.0, 0), 1.0, 0.001) == 1)

    // Test 3: 2.0^(-2) = 0.25
    assert(near(pow_double(2.0, 0 - 2), 0.25, 0.001) == 1)

    // Test 4: 3.0^3 = 27.0
    assert(near(pow_double(3.0, 3), 27.0, 0.001) == 1)

    // Test 5: 0.5^3 = 0.125
    assert(near(pow_double(0.5, 3), 0.125, 0.001) == 1)

    // Test 6: 1.0^1000 = 1.0
    assert(near(pow_double(1.0, 1000), 1.0, 0.001) == 1)

    // Test 7: 10.0^(-1) = 0.1
    assert(near(pow_double(10.0, 0 - 1), 0.1, 0.001) == 1)

    // Test 8: 5.0^1 = 5.0
    assert(near(pow_double(5.0, 1), 5.0, 0.001) == 1)

    // Test 9: 2.0^20 = 1048576.0
    assert(near(pow_double(2.0, 20), 1048576.0, 0.1) == 1)

    // Test 10: 0.0^5 = 0.0
    assert(near(pow_double(0.0, 5), 0.0, 0.001) == 1)

    println("083_pow_double: ALL TESTS PASSED")
    0
}