In the last week I didn’t create any PR which is worth to mention so in this report I’d like to introduce the concept which we’re going to add vector module.

Currently, in SymPy we have transformation equations but they’re responsible only for rotation and translation. We have already implemented the transformation equations for changing type of coordinate system so we need to somehow deals with composition of this two kind of transformation. To do that, firstly we need to implement a method for obtaining transformation equations from rotation matrix. Secondly, we need to create generic method to compose two transformation. In vector module we are in linear regime so from mathematical point of view it is not complicated. We can do that by SymPy’s .subs():

eq11 = f(x,y,z) eq12 = g(z,y,z) eq13 = h(x,y,z) # First set of transformation equations eq21 = a(x,y,z) eq22 = b(x,y,z) eq23 = c(x,y,z) # Second set of transformation equations eq11.subs(x, eq21) eq11.subs(y, eq22) eq11.subs(z, eq23)

After setting first set of transformation equations we need to substitute the variables by second set of transformation equations.