diff --git a/src/einsteinpy/symbolic/__init__.py b/src/einsteinpy/symbolic/__init__.py
index 0ac77d1..ac0ec8f 100644
--- a/src/einsteinpy/symbolic/__init__.py
+++ b/src/einsteinpy/symbolic/__init__.py
@@ -1,3 +1,4 @@
+from .auxillary_functions import simplify_sympy_array
 from .christoffel import ChristoffelSymbols
 from .constants import SymbolicConstant, get_constant
 from .einstein import EinsteinTensor
diff --git a/src/einsteinpy/symbolic/auxillary_functions.py b/src/einsteinpy/symbolic/auxillary_functions.py
new file mode 100644
index 0000000..46fcd32
--- /dev/null
+++ b/src/einsteinpy/symbolic/auxillary_functions.py
@@ -0,0 +1,16 @@
+import sympy
+
+
+def _flatten_list(seq):
+    # flatten an arbitarily nested list
+    if not seq:
+        return []
+    if not isinstance(seq[0], list):
+        return [seq[0]] + _flatten_list(seq[1:])
+    return _flatten_list(seq[0]) + _flatten_list(seq[1:])
+
+
+def simplify_sympy_array(arr):
+    flattened_list = _flatten_list(arr.tolist())
+    simplified_flattened_list = [sympy.simplify(e) for e in flattened_list]
+    return sympy.Array(simplified_flattened_list, arr.shape)
diff --git a/src/einsteinpy/symbolic/ricci.py b/src/einsteinpy/symbolic/ricci.py
index f9049b2..c56ea1e 100644
--- a/src/einsteinpy/symbolic/ricci.py
+++ b/src/einsteinpy/symbolic/ricci.py
@@ -171,7 +171,7 @@ class RicciScalar(BaseRelativityTensor):
             arr=arr, syms=syms, config="", parent_metric=parent_metric
         )
         self._order = 0
-        self._expr = self.arr[0]
+        self._expr = sum(self.arr)  # sympy not allowing indexing, temporary fix!
 
     @property
     def expr(self):
diff --git a/src/einsteinpy/symbolic/tensor.py b/src/einsteinpy/symbolic/tensor.py
index a9da56b..831c0f2 100644
--- a/src/einsteinpy/symbolic/tensor.py
+++ b/src/einsteinpy/symbolic/tensor.py
@@ -4,6 +4,8 @@ from sympy import simplify, tensorcontraction, tensorproduct
 from sympy.core.expr import Expr
 from sympy.core.function import AppliedUndef, UndefinedFunction
 
+from einsteinpy.symbolic.auxillary_functions import simplify_sympy_array
+
 
 def _config_checker(config):
     # check if the string for config contains 'u' and 'l' only
@@ -51,11 +53,8 @@ def _change_config(tensor, metric, newconfig):
                     tensorcontraction(tensorproduct(met_dict[action], t), (1, 2 + i))
                 )
                 # reshuffle the indices
-                tmp = np.array(t).reshape(t.shape)
-                source, dest = (
-                    [p for p in range(len(t.shape))],
-                    [p for p in range(len(t.shape))],
-                )
+                tmp = np.array(t.tolist()).reshape(t.shape)
+                source, dest = list(range(len(t.shape))), list(range(len(t.shape)))
                 dest.pop(i)
                 dest.insert(0, i)
                 tmp = np.moveaxis(tmp, source, dest)
@@ -181,7 +180,8 @@ class Tensor:
             Simplified Tensor
 
         """
-        return sympy.simplify(self.tensor())
+        # return sympy.simplify(self.tensor())  # this used to work with older sympy versions
+        return simplify_sympy_array(self.tensor())
 
 
 class BaseRelativityTensor(Tensor):
@@ -338,3 +338,41 @@ class BaseRelativityTensor(Tensor):
             numeric_arr = sympy.lambdify(args, self.arr, np)
             arg_list = tuple(args)
         return arg_list, numeric_arr
+
+    def lorentz_transform(self, transformation_matrix):
+        """
+        Performs a Lorentz transform on the tensor.
+
+        Parameters
+        ----------
+            transformation_matrix : ~sympy.tensor.array.dense_ndim_array.ImmutableDenseNDimArray or list
+                Sympy Array or multi-dimensional list containing Sympy Expressions
+
+        Returns
+        -------
+            ~einsteinpy.symbolic.tensor.BaseRelativityTensor
+                lorentz transformed tensor(or vector)
+
+        """
+        tm = sympy.Array(transformation_matrix)
+        t = self.tensor()
+        for i in range(self.order):
+            if self.config[i] == "u":
+                t = simplify(tensorcontraction(tensorproduct(tm, t), (1, 2 + i)))
+            else:
+                t = simplify(tensorcontraction(tensorproduct(tm, t), (0, 2 + i)))
+            tmp = np.array(t.tolist()).reshape(t.shape)
+            source, dest = list(range(len(t.shape))), list(range(len(t.shape)))
+            dest.pop(i)
+            dest.insert(0, i)
+            tmp = np.moveaxis(tmp, source, dest)
+            t = sympy.Array(tmp)
+
+        return BaseRelativityTensor(
+            t,
+            syms=self.syms,
+            config=self.config,
+            parent_metric=None,
+            variables=self.variables,
+            functions=self.functions,
+        )
diff --git a/src/einsteinpy/symbolic/vector.py b/src/einsteinpy/symbolic/vector.py
index c74b5c9..478019a 100644
--- a/src/einsteinpy/symbolic/vector.py
+++ b/src/einsteinpy/symbolic/vector.py
@@ -75,3 +75,24 @@ class GenericVector(BaseRelativityTensor):
             new_tensor, self.syms, config=newconfig, parent_metric=metric
         )
         return new_obj
+
+    def lorentz_transform(self, transformation_matrix):
+        """
+        Performs a Lorentz transform on the vector.
+
+        Parameters
+        ----------
+            transformation_matrix : ~sympy.tensor.array.dense_ndim_array.ImmutableDenseNDimArray or list
+                Sympy Array or multi-dimensional list containing Sympy Expressions
+
+        Returns
+        -------
+            ~einsteinpy.symbolic.vector.GenericVector
+                lorentz transformed vector
+
+        """
+
+        t = super(GenericVector, self).lorentz_transform(transformation_matrix)
+        return GenericVector(
+            t.tensor(), syms=self.syms, config=self.config, parent_metric=None
+        )

Implement Lorentz transform feature for Tensors(Symbolic Module)
🐞 **Problem**
Given a Lorentz matrix, give an option to change coordinates of tensors, taking into account the index configuration of tensors.


💡 **Possible solutions**

![image](https://user-images.githubusercontent.com/24695764/71483412-c0b5ca00-282d-11ea-9963-6e1e7378bc8f.jpg)


📋  **Steps to solve the problem**

 * Comment below about what you've started working on.
 * Add, commit, push your changes
 * Submit a pull request and add this in comments - `Addresses #<put issue number here>`
 * Ask for a review in comments section of pull request
 * Celebrate your contribution to this project 🎉

diff --git a/src/einsteinpy/tests/test_symbolic/test_schouten.py b/src/einsteinpy/tests/test_symbolic/test_schouten.py
index 2576395..fa397fa 100644
--- a/src/einsteinpy/tests/test_symbolic/test_schouten.py
+++ b/src/einsteinpy/tests/test_symbolic/test_schouten.py
@@ -8,6 +8,7 @@ from einsteinpy.symbolic import (
     RicciTensor,
     RiemannCurvatureTensor,
     SchoutenTensor,
+    simplify_sympy_array,
 )
 
 
@@ -84,5 +85,5 @@ def test_SchoutenTensor_config_change():
     t3 = t2.change_config("ll")
     assert t1.config == "ll" and t3.config == "ll"
     compare = sympy.Array(np.zeros((4, 4), dtype=int))
-    testarr = sympy.simplify(t1.tensor() - t3.tensor())
+    testarr = simplify_sympy_array(t1.tensor() - t3.tensor())
     assert testarr == compare
diff --git a/src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py b/src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py
index 8508119..fc8689c 100644
--- a/src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py
+++ b/src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py
@@ -2,7 +2,11 @@ import numpy as np
 import sympy
 from sympy import cos, sin, sinh
 
-from einsteinpy.symbolic import MetricTensor, StressEnergyMomentumTensor
+from einsteinpy.symbolic import (
+    MetricTensor,
+    StressEnergyMomentumTensor,
+    simplify_sympy_array,
+)
 
 
 def schwarzschild_metric():
@@ -50,5 +54,5 @@ def test_StressEnergyMomentumTensor_cyclic_config_change():
     t3 = t2.change_config("ll")
     assert t1.config == "ll" and t3.config == "ll"
     compare = sympy.Array(np.zeros((4, 4), dtype=int))
-    testarr = sympy.simplify(t1.tensor() - t3.tensor())
+    testarr = simplify_sympy_array(t1.tensor() - t3.tensor())
     assert testarr == compare
diff --git a/src/einsteinpy/tests/test_symbolic/test_vector.py b/src/einsteinpy/tests/test_symbolic/test_vector.py
index ff56cc0..a7f5f50 100644
--- a/src/einsteinpy/tests/test_symbolic/test_vector.py
+++ b/src/einsteinpy/tests/test_symbolic/test_vector.py
@@ -1,5 +1,5 @@
 import numpy as np
-from sympy import cos, simplify, symbols
+from sympy import cos, cosh, simplify, sinh, symbols
 
 from einsteinpy.symbolic import GenericVector, MetricTensor
 
@@ -46,3 +46,28 @@ def test_GenericVector_check_ValueErrors():
     except ValueError:
         boolstore = True
     assert boolstore
+
+
+def test_lorentz_transform():
+    def get_vector():
+        syms = symbols("t x y z")
+        t, x, y, z = syms
+        return GenericVector([t, x, y, z], syms=syms, config="u")
+
+    def get_lorentz_matrix():
+        list2d = [[0 for t1 in range(4)] for t2 in range(4)]
+        phi = symbols("phi")
+        list2d[0][0], list2d[0][1], list2d[1][0], list2d[1][1] = (
+            cosh(phi),
+            -sinh(phi),
+            -sinh(phi),
+            cosh(phi),
+        )
+        list2d[2][2], list2d[3][3] = 1, 1
+        return list2d
+
+    t, x, phi = symbols("t x phi")
+    v = get_vector().lorentz_transform(get_lorentz_matrix())
+    print(v.tensor())
+    assert simplify(v[0] - (t * cosh(phi) - x * sinh(phi))) == 0
+    assert simplify(v[1] - (x * cosh(phi) - t * sinh(phi))) == 0
diff --git a/src/einsteinpy/tests/test_symbolic/test_weyl.py b/src/einsteinpy/tests/test_symbolic/test_weyl.py
index 4ac1cf3..9b7fc6d 100644
--- a/src/einsteinpy/tests/test_symbolic/test_weyl.py
+++ b/src/einsteinpy/tests/test_symbolic/test_weyl.py
@@ -8,6 +8,7 @@ from einsteinpy.symbolic import (
     RicciTensor,
     RiemannCurvatureTensor,
     WeylTensor,
+    simplify_sympy_array,
 )
 
 
@@ -85,7 +86,7 @@ def test_weyl_conformal_rescaling():
     w1 = WeylTensor.from_metric(mw1).change_config("ulll")
     w2 = WeylTensor.from_metric(mw2).change_config("ulll")
     cmp_arr = sympy.Array(np.zeros(shape=w1.tensor().shape, dtype=int))
-    assert sympy.simplify(w1.tensor() - w2.tensor()) == cmp_arr
+    assert simplify_sympy_array(w1.tensor() - w2.tensor()) == cmp_arr
     assert w1.syms == w1.symbols()
     assert w1.parent_metric == w1._parent_metric
 
@@ -93,7 +94,7 @@ def test_weyl_conformal_rescaling():
 def test_weyl_contraction_1st_3rd_indices_zero():
     mw1 = anti_de_sitter_metric()
     w1 = WeylTensor.from_metric(mw1)
-    t1 = sympy.simplify(
+    t1 = simplify_sympy_array(
         sympy.tensorcontraction(w1.change_config("ulll").tensor(), (0, 2))
     )
     t0 = sympy.Array(np.zeros(shape=t1.shape, dtype=int))

pip install -e .[dev]
parse_log_pytest
pytest
pytest
3.6
pytest --no-header -rA --tb=line --color=no -p no:cacheprovider -W ignore::DeprecationWarning
alabaster==0.7.13
argon2-cffi==21.3.0
argon2-cffi-bindings==21.2.0
astropy==4.1
async-generator==1.10
attrs @ file:///opt/conda/conda-bld/attrs_1642510447205/work
Babel==2.11.0
backcall==0.2.0
black==22.8.0
bleach==4.1.0
certifi==2021.5.30
cffi==1.15.1
charset-normalizer==2.0.12
click==8.0.4
comm==0.1.4
coverage==6.2
cycler==0.11.0
dataclasses==0.8
decorator==5.1.1
defusedxml==0.7.1
distlib==0.3.9
docutils==0.18.1
-e git+https://github.com/einsteinpy/einsteinpy.git@66eeba86bef20cc779c644de100ddde140c7104b#egg=einsteinpy
entrypoints==0.4
execnet==1.9.0
filelock==3.4.1
idna==3.10
imagesize==1.4.1
importlib-metadata==4.8.3
importlib-resources==5.4.0
iniconfig @ file:///home/linux1/recipes/ci/iniconfig_1610983019677/work
ipykernel==5.5.6
ipython==7.16.3
ipython-genutils==0.2.0
ipywidgets==7.8.5
isort==5.10.1
jedi==0.17.2
Jinja2==3.0.3
jsonschema==3.2.0
jupyter-client==7.1.2
jupyter-core==4.9.2
jupyter-sphinx==0.4.0
jupyterlab-pygments==0.1.2
jupyterlab_widgets==1.1.11
kiwisolver==1.3.1
llvmlite==0.36.0
MarkupSafe==2.0.1
matplotlib==3.3.4
mistune==0.8.4
more-itertools @ file:///tmp/build/80754af9/more-itertools_1637733554872/work
mpmath==1.3.0
mypy-extensions==1.0.0
nbclient==0.5.9
nbconvert==6.0.7
nbformat==5.1.3
nbsphinx==0.8.8
nest-asyncio==1.6.0
notebook==6.4.10
numba==0.53.1
numpy==1.19.5
packaging @ file:///tmp/build/80754af9/packaging_1637314298585/work
pandocfilters==1.5.1
parso==0.7.1
pathspec==0.9.0
pexpect==4.9.0
pickleshare==0.7.5
Pillow==8.4.0
platformdirs==2.4.0
plotly==5.18.0
pluggy @ file:///tmp/build/80754af9/pluggy_1615976315926/work
prometheus-client==0.17.1
prompt-toolkit==3.0.36
ptyprocess==0.7.0
py @ file:///opt/conda/conda-bld/py_1644396412707/work
pycodestyle==2.10.0
pycparser==2.21
Pygments==2.14.0
pyparsing @ file:///tmp/build/80754af9/pyparsing_1635766073266/work
pyrsistent==0.18.0
pytest==6.2.4
pytest-cov==2.5.1
pytest-xdist==3.0.2
python-dateutil==2.9.0.post0
pytz==2025.2
pyzmq==25.1.2
requests==2.27.1
scipy==1.5.4
Send2Trash==1.8.3
six==1.17.0
snowballstemmer==2.2.0
Sphinx==5.3.0
sphinxcontrib-applehelp==1.0.2
sphinxcontrib-devhelp==1.0.2
sphinxcontrib-htmlhelp==2.0.0
sphinxcontrib-jsmath==1.0.1
sphinxcontrib-qthelp==1.0.3
sphinxcontrib-serializinghtml==1.1.5
sympy==1.9
tenacity==8.2.2
terminado==0.12.1
testpath==0.6.0
toml @ file:///tmp/build/80754af9/toml_1616166611790/work
tomli==1.2.3
tornado==6.1
tox==3.28.0
traitlets==4.3.3
typed-ast==1.5.5
typing_extensions @ file:///opt/conda/conda-bld/typing_extensions_1647553014482/work
urllib3==1.26.20
virtualenv==20.17.1
wcwidth==0.2.13
webencodings==0.5.1
widgetsnbextension==3.6.10
zipp @ file:///tmp/build/80754af9/zipp_1633618647012/work

name: einsteinpy
channels:
  - defaults
  - https://repo.anaconda.com/pkgs/main
  - https://repo.anaconda.com/pkgs/r
  - conda-forge
dependencies:
  - _libgcc_mutex=0.1=main
  - _openmp_mutex=5.1=1_gnu
  - attrs=21.4.0=pyhd3eb1b0_0
  - ca-certificates=2025.2.25=h06a4308_0
  - certifi=2021.5.30=py36h06a4308_0
  - importlib_metadata=4.8.1=hd3eb1b0_0
  - iniconfig=1.1.1=pyhd3eb1b0_0
  - ld_impl_linux-64=2.40=h12ee557_0
  - libffi=3.3=he6710b0_2
  - libgcc-ng=11.2.0=h1234567_1
  - libgomp=11.2.0=h1234567_1
  - libstdcxx-ng=11.2.0=h1234567_1
  - more-itertools=8.12.0=pyhd3eb1b0_0
  - ncurses=6.4=h6a678d5_0
  - openssl=1.1.1w=h7f8727e_0
  - packaging=21.3=pyhd3eb1b0_0
  - pip=21.2.2=py36h06a4308_0
  - pluggy=0.13.1=py36h06a4308_0
  - py=1.11.0=pyhd3eb1b0_0
  - pyparsing=3.0.4=pyhd3eb1b0_0
  - pytest=6.2.4=py36h06a4308_2
  - python=3.6.13=h12debd9_1
  - readline=8.2=h5eee18b_0
  - setuptools=58.0.4=py36h06a4308_0
  - sqlite=3.45.3=h5eee18b_0
  - tk=8.6.14=h39e8969_0
  - toml=0.10.2=pyhd3eb1b0_0
  - typing_extensions=4.1.1=pyh06a4308_0
  - wheel=0.37.1=pyhd3eb1b0_0
  - xz=5.6.4=h5eee18b_1
  - zipp=3.6.0=pyhd3eb1b0_0
  - zlib=1.2.13=h5eee18b_1
  - pip:
      - alabaster==0.7.13
      - argon2-cffi==21.3.0
      - argon2-cffi-bindings==21.2.0
      - astropy==4.1
      - async-generator==1.10
      - babel==2.11.0
      - backcall==0.2.0
      - black==22.8.0
      - bleach==4.1.0
      - cffi==1.15.1
      - charset-normalizer==2.0.12
      - click==8.0.4
      - comm==0.1.4
      - coverage==6.2
      - cycler==0.11.0
      - dataclasses==0.8
      - decorator==5.1.1
      - defusedxml==0.7.1
      - distlib==0.3.9
      - docutils==0.18.1
      - entrypoints==0.4
      - execnet==1.9.0
      - filelock==3.4.1
      - idna==3.10
      - imagesize==1.4.1
      - importlib-metadata==4.8.3
      - importlib-resources==5.4.0
      - ipykernel==5.5.6
      - ipython==7.16.3
      - ipython-genutils==0.2.0
      - ipywidgets==7.8.5
      - isort==5.10.1
      - jedi==0.17.2
      - jinja2==3.0.3
      - jsonschema==3.2.0
      - jupyter-client==7.1.2
      - jupyter-core==4.9.2
      - jupyter-sphinx==0.4.0
      - jupyterlab-pygments==0.1.2
      - jupyterlab-widgets==1.1.11
      - kiwisolver==1.3.1
      - llvmlite==0.36.0
      - markupsafe==2.0.1
      - matplotlib==3.3.4
      - mistune==0.8.4
      - mpmath==1.3.0
      - mypy-extensions==1.0.0
      - nbclient==0.5.9
      - nbconvert==6.0.7
      - nbformat==5.1.3
      - nbsphinx==0.8.8
      - nest-asyncio==1.6.0
      - notebook==6.4.10
      - numba==0.53.1
      - numpy==1.19.5
      - pandocfilters==1.5.1
      - parso==0.7.1
      - pathspec==0.9.0
      - pexpect==4.9.0
      - pickleshare==0.7.5
      - pillow==8.4.0
      - platformdirs==2.4.0
      - plotly==5.18.0
      - prometheus-client==0.17.1
      - prompt-toolkit==3.0.36
      - ptyprocess==0.7.0
      - pycodestyle==2.10.0
      - pycparser==2.21
      - pygments==2.14.0
      - pyrsistent==0.18.0
      - pytest-cov==2.5.1
      - pytest-xdist==3.0.2
      - python-dateutil==2.9.0.post0
      - pytz==2025.2
      - pyzmq==25.1.2
      - requests==2.27.1
      - scipy==1.5.4
      - send2trash==1.8.3
      - six==1.17.0
      - snowballstemmer==2.2.0
      - sphinx==5.3.0
      - sphinxcontrib-applehelp==1.0.2
      - sphinxcontrib-devhelp==1.0.2
      - sphinxcontrib-htmlhelp==2.0.0
      - sphinxcontrib-jsmath==1.0.1
      - sphinxcontrib-qthelp==1.0.3
      - sphinxcontrib-serializinghtml==1.1.5
      - sympy==1.9
      - tenacity==8.2.2
      - terminado==0.12.1
      - testpath==0.6.0
      - tomli==1.2.3
      - tornado==6.1
      - tox==3.28.0
      - traitlets==4.3.3
      - typed-ast==1.5.5
      - urllib3==1.26.20
      - virtualenv==20.17.1
      - wcwidth==0.2.13
      - webencodings==0.5.1
      - widgetsnbextension==3.6.10
prefix: /opt/conda/envs/einsteinpy

src/einsteinpy/tests/test_symbolic/test_schouten.py::test_SchoutenTensor_parent_metric_property_and_ValueError src/einsteinpy/tests/test_symbolic/test_schouten.py::test_Schouten_dim2 src/einsteinpy/tests/test_symbolic/test_schouten.py::test_SchoutenTensor_with_arbritary_config src/einsteinpy/tests/test_symbolic/test_schouten.py::test_SchoutenTensor_config_change src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py::test_StressEnergyMomentumTensor_ValueError_wrong_config_length src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py::test_StressEnergyMomentumTensor_change_config_no_parent_metric src/einsteinpy/tests/test_symbolic/test_stress_energy_momentum.py::test_StressEnergyMomentumTensor_cyclic_config_change src/einsteinpy/tests/test_symbolic/test_vector.py::test_GenericVector_change_config_theoretical_test src/einsteinpy/tests/test_symbolic/test_vector.py::test_GenericVector_check_ValueErrors src/einsteinpy/tests/test_symbolic/test_vector.py::test_lorentz_transform src/einsteinpy/tests/test_symbolic/test_weyl.py::test_weyl_TypeError src/einsteinpy/tests/test_symbolic/test_weyl.py::test_weyl_ValueError_wrong_config_length src/einsteinpy/tests/test_symbolic/test_weyl.py::test_weyl_dim2 src/einsteinpy/tests/test_symbolic/test_weyl.py::test_weyl_dim3 src/einsteinpy/tests/test_symbolic/test_weyl.py::test_weyl_conformal_rescaling src/einsteinpy/tests/test_symbolic/test_weyl.py::test_weyl_contraction_1st_3rd_indices_zero
src/einsteinpy/symbolic/vector.py src/einsteinpy/symbolic/__init__.py src/einsteinpy/symbolic/ricci.py src/einsteinpy/symbolic/tensor.py src/einsteinpy/symbolic/auxillary_functions.py
src/einsteinpy/symbolic/vector.py src/einsteinpy/symbolic/__init__.py src/einsteinpy/symbolic/ricci.py src/einsteinpy/symbolic/tensor.py src/einsteinpy/symbolic/auxillary_functions.py