Reference-Scaled Numerical Error Percentage Calculator

            from math import *

def numerical_relative_error_calculator(a, b) -> float:
    return ((100.0 * a) / b)

assert abs(numerical_relative_error_calculator(0.08, 4) - 2) < 1e-6 * max(1.0, abs(2))
          

            #include <assert.h>
#include <math.h>

double numerical_relative_error_calculator(double a, double b) {
    return ((100.0 * a) / b);
}

int main(void) {
    const double expected = 2;
    const double actual = numerical_relative_error_calculator(0.08, 4);
    assert(fabs(actual - expected) < 1e-6 * fmax(1.0, fabs(expected)));
}
          

            #include <cassert>
#include <cmath>
#include <numbers>

double numerical_relative_error_calculator(double a, double b) {
    return ((100.0 * a) / b);
}

int main() {
    constexpr double expected = 2;
    const double actual = numerical_relative_error_calculator(0.08, 4);
    assert(std::fabs(actual - expected) < 1e-6 * std::fmax(1.0, std::fabs(expected)));
}
          

x86-64 NASM · System V ABI · Linux · SSE2 with libm where required

            ; double numerical_relative_error_calculator(double a, double b)
; Linux x86-64 NASM · System V ABI · first eight doubles in xmm0–xmm7
global numerical_relative_error_calculator
section .text

numerical_relative_error_calculator:
    push rbp
    mov rbp, rsp
    sub rsp, 48
    movsd [rbp-8], xmm0
    movsd [rbp-16], xmm1
    mov rax, 0x4059000000000000
    movq xmm0, rax
    movsd [rbp-40], xmm0
    movsd xmm0, [rbp-40]
    mulsd xmm0, [rbp-8]
    movsd [rbp-32], xmm0
    movsd xmm0, [rbp-32]
    divsd xmm0, [rbp-16]
    movsd [rbp-24], xmm0
    movsd xmm0, [rbp-24]
    leave
    ret
          

            function result = numerical_relative_error_calculator(a, b)
    result = ((100.0 * a) / b);
end
          

            ClearAll[mwCalculate];
mwCalculate[a_, b_] := ((100.0 * a) / b);