Compile過後的Mathematica程序大概比Python編的慢多少？

01-29

兩個分別同時用函數式編程或過程式的情況下

為什麼認為Mathematica一定比Python慢？Compile後的Mathematica程序和PyPy或者numba比還差不多。

以計算Mandelbrot set為例

Mathematica code，運行時間0.031s

mandelbrot = Compile[{x, y}, Block[{BAILOUT = 16, MAXITERATIONS = 1000, cr = y - 0.5, ci = x, zi = 0.0, zr = 0.0, i = 0, temp, zr2, zi2}, While[True, i++; temp = zr zi; zr2 = zr zr; zi2 = zi zi; zr = zr2 - zi2 + cr; zi = temp + temp + ci; If[zi2 + zr2 &> BAILOUT, Return@i]; If[i &> MAXITERATIONS, Return@0]]; 0], CompilationTarget -&> "C", RuntimeOptions -&> "Speed" ];

t1 = TimeUsed[]; write = WriteString["stdout", #] ; Do[ Do[ write[If[mandelbrot[x/40.0, y/40.0] == 0, "*", " "]], {y, -39, 38} ]; write[" "], {x, -39, 38} ]; TimeUsed[] - t1

Python code，運行時間1.0257s

from time import time import sys t0=time()


def mandelbrot(x, y):

    BAILOUT = 16

    MAX_ITERATIONS = 1000

    cr = y - 0.5

    ci = x

    zi = 0.0

    zr = 0.0

    i = 0

    while True:

        i += 1

        temp = zr * zi

        zr2 = zr * zr

        zi2 = zi * zi

        zr = zr2 - zi2 + cr

        zi = temp + temp + ci

        if zi2 + zr2 &> BAILOUT:

            return i

        if i &> MAX_ITERATIONS:

            return 0
def main():

    for y in range(-39, 39):

        sys.stdout.write(

)

        for x in range(-39, 39):

            if mandelbrot(x / 40.0, y / 40.0) == 0:

                sys.stdout.write(*)

            else:

                sys.stdout.write( )

    print()

main() print(time()-t0)