Bugfix for aspect ratio in symbolic IP issue

[jodemaey]

Fixing the issue #17

[jodemaey]

All test are now passing:

========================================================================== test session starts ==========================================================================
platform linux -- Python 3.8.16, pytest-7.2.1, pluggy-1.0.0
rootdir: /home/jodemaey/Work/models/qgs
plugins: anyio-3.6.2
collected 8 items                                                                                                                                                       

model_test/test_aotensor.py .                                                                                                                                     [ 12%]
model_test/test_aotensor_6x6.py .                                                                                                                                 [ 25%]
model_test/test_aotensor_jacobian.py .                                                                                                                            [ 37%]
model_test/test_inner_products.py ..                                                                                                                              [ 62%]
model_test/test_inner_products_6x6.py .                                                                                                                           [ 75%]
model_test/test_tlad.py ..                                                                                                                                        [100%]

=========================================================================== warnings summary ============================================================================
../../../anaconda3/envs/qgs_new/lib/python3.8/site-packages/sparse/_coo/core.py:261: 18015 warnings
model_test/test_aotensor.py: 24611 warnings
model_test/test_aotensor_6x6.py: 7781859 warnings
model_test/test_aotensor_jacobian.py: 24611 warnings
model_test/test_inner_products.py: 28 warnings
model_test/test_inner_products_6x6.py: 14 warnings
  /home/jodemaey/anaconda3/envs/qgs_new/lib/python3.8/site-packages/sparse/_coo/core.py:261: DeprecationWarning: coords should be an ndarray. This will raise a ValueError in the future.
    warnings.warn(

-- Docs: https://docs.pytest.org/en/stable/how-to/capture-warnings.html
=========================================================== 8 passed, 7849138 warnings in 1339.62s (0:22:19) ============================================================