##What is Pynstein? Pynstein is a python library that allows the user to easily do general relativity calculations.
##Features
- Given a metric, Pynstein can calculate:
- Inverse metrics
- Christoffel Symbols
- Reimann Curvature Tensor
- Ricci Curvature Tensor
- Conservation equation
- Einstein Tensor
- and given the stress energy tensor, the Einstein Equations
- Can numerically evolve a universe given initial conditions
##Dependencies
- numpy
- scipy
- sympy
- matplotlib
##Example Usage
#Define variables
t = sp.Symbol('t')
r = sp.Symbol('r')
theta = sp.Symbol('theta')
phi = sp.Symbol('phi')
#Define rho and p functions
w = sp.Symbol('w')
rho = sp.Function('rho')(t)
p = w*rho
#Create FRW metric
frw_metric = np.diag([-1, a**2/(1-k*r**2), a**2*r**2,a**2*r**2*sp.sin(theta)**2])
frw_metric_key = [t, r, theta, phi]
#Generate Einstein tensor
einstein = einstein_tensor_from_scratch(frw_metric, frw_metric_key)
einstein = raise_one_index(einstein, frw_metric)
#Generate the 2 distinct Einstein field equations
ein_eq = einstein_equations(einstein, np.diag([-rho, p, p, p]))##Authors Kai Smith ([email protected])
David Clark ([email protected])
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