Photon Energy and Wavelength Calculator

            from math import *

def photon_energy(a) -> float:
    return ((6.62607015e-34 * 299792458.0) / (a * 1e-9))

assert abs(photon_energy(500) - 3.9728917142978563e-19) < 1e-6 * max(1.0, abs(3.9728917142978563e-19))
          

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

double photon_energy(double a) {
    return ((6.62607015e-34 * 299792458.0) / (a * 1e-9));
}

int main(void) {
    const double expected = 3.9728917142978563e-19;
    const double actual = photon_energy(500);
    assert(fabs(actual - expected) < 1e-6 * fmax(1.0, fabs(expected)));
}
          

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

double photon_energy(double a) {
    return ((6.62607015e-34 * 299792458.0) / (a * 1e-9));
}

int main() {
    constexpr double expected = 3.9728917142978563e-19;
    const double actual = photon_energy(500);
    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 photon_energy(double a)
; Linux x86-64 NASM · System V ABI · first eight doubles in xmm0–xmm7
global photon_energy
section .text

photon_energy:
    push rbp
    mov rbp, rsp
    sub rsp, 64
    movsd [rbp-8], xmm0
    mov rax, 0x390b860bde023111
    movq xmm0, rax
    movsd [rbp-32], xmm0
    mov rax, 0x41b1de784a000000
    movq xmm0, rax
    movsd [rbp-40], xmm0
    movsd xmm0, [rbp-32]
    mulsd xmm0, [rbp-40]
    movsd [rbp-24], xmm0
    mov rax, 0x3e112e0be826d695
    movq xmm0, rax
    movsd [rbp-56], xmm0
    movsd xmm0, [rbp-8]
    mulsd xmm0, [rbp-56]
    movsd [rbp-48], xmm0
    movsd xmm0, [rbp-24]
    divsd xmm0, [rbp-48]
    movsd [rbp-16], xmm0
    movsd xmm0, [rbp-16]
    leave
    ret
          

            function result = photon_energy(a)
    result = ((6.62607015e-34 * 299792458.0) / (a * 1e-9));
end
          

            ClearAll[mwCalculate];
mwCalculate[a_] := ((6.62607015e-34 * 299792458.0) / (a * 1e-9));