solve_ivp - TypeError: 'numpy.ndarray' object is not callable-CodePudding

I'm working on the code below for a class and no matter what I try I can't figure out how to fix it so I can move on.

def eqs(t, x):
    return np.array([[(1 - np.multiply((1 - f(z(t), z_thresh)), (1 - f(x(1), y_thresh)))) - x(0)],
                                [(1 - np.multiply((1 - f(z(t), z_thresh)),(1 - f(x(0), x_thresh)))) - x(1)]])


f = lambda x, thresh: x >= thresh
z = lambda t: np.multiply((t >= 2), (t <= 4))

z_thresh = 0.5
y_thresh = 0.5
x_thresh = 0.5

x_0 = np.zeros([0,])

sol = int.solve_ivp(eqs, range(0, 6), x_0)

I've been banging my head against the wall all night and can't figure out how to get around. No matter what I seem to try it still throws "TypeError: 'numpy.ndarray' object is not callable."

Edit: The traceback is as follows:

Traceback (most recent call last)
~\AppData\Local\Temp/ipykernel_7252/1552450284.py in <module>
      9 x0 = np.zeros([0,])
     10 
---> 11 sol = int.solve_ivp(eqns_a,range(0,6),x0)
     12 plt.figure(1)
     13 subplot(311)

~\anaconda3\lib\site-packages\scipy\integrate\_ivp\ivp.py in solve_ivp(fun, t_span, y0, method, t_eval, dense_output, events, vectorized, args, **options)
    540         method = METHODS[method]
    541 
--> 542     solver = method(fun, t0, y0, tf, vectorized=vectorized, **options)
    543 
    544     if t_eval is None:

~\anaconda3\lib\site-packages\scipy\integrate\_ivp\rk.py in __init__(self, fun, t0, y0, t_bound, max_step, rtol, atol, vectorized, first_step, **extraneous)
     92         self.max_step = validate_max_step(max_step)
     93         self.rtol, self.atol = validate_tol(rtol, atol, self.n)
---> 94         self.f = self.fun(self.t, self.y)
     95         if first_step is None:
     96             self.h_abs = select_initial_step(

~\anaconda3\lib\site-packages\scipy\integrate\_ivp\base.py in fun(t, y)
    136         def fun(t, y):
    137             self.nfev  = 1
--> 138             return self.fun_single(t, y)
    139 
    140         self.fun = fun

~\anaconda3\lib\site-packages\scipy\integrate\_ivp\base.py in fun_wrapped(t, y)
     18 
     19     def fun_wrapped(t, y):
---> 20         return np.asarray(fun(t, y), dtype=dtype)
     21 
     22     return fun_wrapped, y0

~\AppData\Local\Temp/ipykernel_7252/1552450284.py in <lambda>(t, x)
      6 x_thresh = 0.5
      7 
----> 8 eqns_a = lambda t, x: np.array([[(1 - np.multiply((1 - f(z(t), z_thresh)), (1 - f(x(1), y_thresh)))) - x(0)], [(1 - np.multiply((1 - f(z(t), z_thresh)),(1 - f(x(0), x_thresh)))) - x(1)]])
      9 x0 = np.zeros([0,])
     10 

TypeError: 'numpy.ndarray' object is not callable

CodePudding user response：

the traceback tells you that the problem is in

np.array([[(1 - np.multiply((1 - f(z(t), z_thresh)), (1 - f(x(1), y_thresh)))) - x(0)], [(1 - np.multiply((1 - f(z(t), z_thresh)),(1 - f(x(0), x_thresh)))) - x(1)]]

So we look for apparent function calls, fn(...). np.multiply should be ok unless you redefined it somplace. f(...) is defined with a lambda. z(...) as well. That leaves x(1) and x(0). What is x? It's the lambda function argument.