Use tensorflow CPU

.gitlab-ci.yml

@@ -69,7 +69,7 @@ full:
     - python -m pip install -U cppimport pybind11
     - python -m pip install --upgrade git+https://github.com/sympy/sympy.git
     - python -m pip install --upgrade pip setuptools wheel
-    - python -m pip install --upgrade tensorflow-gpu==2.0
+    - python -m pip install --upgrade tensorflow==2.0
     - python -m pip install -e .
     - python -m pip install git+https://i10git.cs.fau.de/seitz/pystencils.git
     - pytest