gpu-programming

As shown in taichi-dev/taichi#3910, replacing property with simple attributes can speedup python part of taichi a lot.
Lessons learned is that we should avoid using @property when applicable since it's expensive. So let's review the usage of @property in our python codebase and replace them as much as possible.

Here's a list of simple grep in our codebase showing

https://github.com/brendangregg/FlameGraph

For a metric defined by inner_product(tangent_vec_a, tangent_vec_b, base_point), add the possibility to get the same metric scaled by a scalar factor, i.e. scaling * inner_product(tangent_vec_a, tangent_vec_b, base_point).

This could be implemented as:

• a new class, called ScaledMetric that is constructed from the original metric class, and a scalar factor scaling.
• an optional `sc