Central-Difference Derivative function-value change across stencil Solver

            from math import *

def central_difference_derivative_solve_a(c, b) -> float:
    return (c * b)

assert abs(central_difference_derivative_solve_a(6.999999999999999, 0.4) - 2.8) < 1e-6 * max(1.0, abs(2.8))
          

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

double central_difference_derivative_solve_a(double c, double b) {
    return (c * b);
}

int main(void) {
    const double expected = 2.8;
    const double actual = central_difference_derivative_solve_a(6.999999999999999, 0.4);
    assert(fabs(actual - expected) < 1e-6 * fmax(1.0, fabs(expected)));
}
          

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

double central_difference_derivative_solve_a(double c, double b) {
    return (c * b);
}

int main() {
    constexpr double expected = 2.8;
    const double actual = central_difference_derivative_solve_a(6.999999999999999, 0.4);
    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 central_difference_derivative_solve_a(double c, double b)
; Linux x86-64 NASM · System V ABI · first eight doubles in xmm0–xmm7
global central_difference_derivative_solve_a
section .text

central_difference_derivative_solve_a:
    push rbp
    mov rbp, rsp
    sub rsp, 32
    movsd [rbp-8], xmm0
    movsd [rbp-16], xmm1
    movsd xmm0, [rbp-8]
    mulsd xmm0, [rbp-16]
    movsd [rbp-24], xmm0
    movsd xmm0, [rbp-24]
    leave
    ret
          

            function result = central_difference_derivative_solve_a(c, b)
    result = (c * b);
end
          

            ClearAll[mwCalculate];
mwCalculate[c_, b_] := (c * b);