Multiple Vector Summation using Einsum

This is an example of how to properly use the einsum function to compute the summation of multiple vectors.

from csdl_om import Simulatorimport numpy as npfrom csdl import Modelimport csdl

class ExampleMultipleVectorSum(Model):
    def define(self):
        a = np.arange(4)        vec = self.declare_variable('a', val=a)
        # Special operation: sum all the entries of the first and second        # vector to a single scalar        self.register_output('einsum_special2',                             csdl.einsum(vec, vec, subscripts='i,j->'))

sim = Simulator(ExampleMultipleVectorSum())sim.run()
print('a', sim['a'].shape)print(sim['a'])print('einsum_special2', sim['einsum_special2'].shape)print(sim['einsum_special2'])

[0. 1. 2. 3.]einsum_special2 (1,)[36.]