Einstein Tensor Module¶
This module contains the class for obtaining Einstein Tensor related to a Metric belonging to any arbitrary space-time symbolically:
-
class
einsteinpy.symbolic.einstein.EinsteinTensor(arr, syms, config='ll', parent_metric=None, name='EinsteinTensor')[source]¶ Bases:
einsteinpy.symbolic.tensor.BaseRelativityTensorClass for defining Einstein Tensor
Constructor and Initializer
- Parameters
arr (ImmutableDenseNDimArray or list) – Sympy Array or multi-dimensional list containing Sympy Expressions
syms (tuple or list) – Tuple of crucial symbols denoting time-axis, 1st, 2nd, and 3rd axis (t,x1,x2,x3)
config (str) – Configuration of contravariant and covariant indices in tensor. ‘u’ for upper and ‘l’ for lower indices. Defaults to ‘ll’.
parent_metric (MetricTensor or None) – Corresponding Metric for the Einstein Tensor. Defaults to None.
name (str) – Name of the Tensor. Defaults to “EinsteinTensor”.
- Raises
TypeError – Raised when arr is not a list or sympy Array
TypeError – syms is not a list or tuple
ValueError – config has more or less than 2 indices
-
change_config(newconfig='ul', metric=None)[source]¶ Changes the index configuration(contravariant/covariant)
- Parameters
newconfig (str) – Specify the new configuration. Defaults to ‘ul’
metric (MetricTensor or None) – Parent metric tensor for changing indices. Already assumes the value of the metric tensor from which it was initialized if passed with None. Compulsory if somehow does not have a parent metric. Defaults to None.
- Returns
New tensor with new configuration. Defaults to ‘ul’
- Return type
- Raises
Exception – Raised when a parent metric could not be found.
