Single Vector Summation using Einsum

This is an example of how to properly use the einsum function to compute the summation of a single vector.

from csdl_om import Simulatorimport numpy as npfrom csdl import Modelimport csdl

class ExampleVectorSummation(Model):
    def define(self):        a = np.arange(4)        vec = self.declare_variable('a', val=a)
        # Summation of all the entries of a vector        self.register_output('einsum_summ1',                             csdl.einsum(                                 vec,                                 subscripts='i->',                             ))

sim = Simulator(ExampleVectorSummation())sim.run()
print('a', sim['a'].shape)print(sim['a'])print('einsum_summ1', sim['einsum_summ1'].shape)print(sim['einsum_summ1'])

[0. 1. 2. 3.]einsum_summ1 (1,)[6.]