python - How to make a Sympy lambdify(ed) function accept array input? -

i’m trying create function in python 2.7 accepts function handle , number of variables in function input , returns new function calculates gradient of input function. have far.

import sympy sym import numpy np  def getsymbolicgradient(func,numvars):     # initialize variables     g = numvars * [0]      # create symbolic variables     x = sym.symarray('x',numvars)      # calculate gradients     in range(numvars):         g[i] = sym.diff(func(x),x[i])      gradfunc = sym.lambdify(x, g, modules="numpy")      return gradfunc 

say use gradfunc following code:

def myvecfunc(x):     return 2*x[0]**2 + 4*x[1] + 2  gradfunc = getsymbolicgradient(func=myvecfunc, numvars=2) 

if call using 2 separate arguments works, such following:

print( gradfunc(1,2) ) 

however, if call using single argument (say numpy array),

print( gradfunc(np.array([1,2])) ) 

i following error:

typeerror: () takes 2 arguments (1 given)

how can lambdify accept input arguments single array inside of individual values? there better (built-in) sympy methods generating symbolic expression gradient of function accepts arrays inputs?

i'm not familiar numpy, in python can use * operator unpack array values.

a = [2, 4, 6] my_func(*a) 

is logically equivalent to

a = 2 b = 4 c = 6 my_func(a, b, c)