t = tf.placeholder(tf.float32, [None, 1])
x = tf.placeholder(tf.float32, [None, 1])

t = tf.constant(np.linspace(0.0,1.0,100), dtype = tf.float64 )

integ = tf.contrib.integrate.odeint_fixed(model.output,
                                          0.0,
                                          t,
                                          method = "rk4")

...

<ipython-input-5-c79e79b75391> in loss(model, t, x)
     24                                                 0.0,
     25                                                 t,
---> 26                                                 method = "rk4")

...

TypeError: 'Tensor' object is not callable