pythonvectorsympyequationbasis

Geting the scalars of one single vector basis using Sympy

I'm new to the sympy library and I have a relatively simple question. I am writing a 3D vector as follows

from sympy.vector import CoordSys3D
N = CoordSys3D('N')
v = 1*N.i + 4*N.j + 5*N.k

I would like to have access to the scalar from just one of the bases for exemple:

The command v[0] = 1 or v[1] = 4.

Its that possible using Sympy?

Solution

  • You can use dot to extract a component:

    In [57]: from sympy.vector import CoordSys3D, dot
    ...: N = CoordSys3D('N')
    ...: v = 1*N.i + 4*N.j + 5*N.k

In [58]: v
Out[58]: i_N + (4) j_N + (5) k_N

In [59]: dot(v, N.j)
Out[59]: 4