.. DO NOT EDIT.
.. THIS FILE WAS AUTOMATICALLY GENERATED BY SPHINX-GALLERY.
.. TO MAKE CHANGES, EDIT THE SOURCE PYTHON FILE:
.. "examples/gallery_examples/01-apdlmath-examples/scipy_sparse_matrix.py"
.. LINE NUMBERS ARE GIVEN BELOW.
.. only:: html
.. note::
:class: sphx-glr-download-link-note
:ref:`Go to the end <sphx_glr_download_examples_gallery_examples_01-apdlmath-examples_scipy_sparse_matrix.py>`
to download the full example code
.. rst-class:: sphx-glr-example-title
.. _sphx_glr_examples_gallery_examples_01-apdlmath-examples_scipy_sparse_matrix.py:
APDLMath Sparse Matrices and SciPy Sparse Matrices
-------------------------------------------------------------------
This tutorial will show how to get APDLMath sparse matrices from FULL
files to SciPy Sparse Matrices.
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.. code-block:: default
import matplotlib.pylab as plt
from ansys.mapdl.core import launch_mapdl
from ansys.mapdl.core.examples import vmfiles
mapdl = launch_mapdl()
mm = mapdl.math
.. GENERATED FROM PYTHON SOURCE LINES 20-22
Load and solve verification manual example 153. Then load the
stiffness matrix into APDLmath.
.. GENERATED FROM PYTHON SOURCE LINES 22-26
.. code-block:: default
out = mapdl.input(vmfiles["vm153"])
k = mm.stiff(fname="PRSMEMB.full")
k
.. rst-class:: sphx-glr-script-out
.. code-block:: none
Sparse APDLMath Matrix (126, 126)
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Copy this APDLMath Sparse Matrix to a SciPy CSR matrix and plot the
graph of the sparse matrix
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.. code-block:: default
pk = k.asarray()
plt.spy(pk)
.. image-sg:: /examples/gallery_examples/01-apdlmath-examples/images/sphx_glr_scipy_sparse_matrix_001.png
:alt: scipy sparse matrix
:srcset: /examples/gallery_examples/01-apdlmath-examples/images/sphx_glr_scipy_sparse_matrix_001.png
:class: sphx-glr-single-img
.. rst-class:: sphx-glr-script-out
.. code-block:: none
<matplotlib.lines.Line2D object at 0x7f785d18d8e0>
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You can access the 3 vectors that describe this sparse matrix with.
- ``pk.data``
- ``pk.indices``
- ``pk.indptr``
See the ``scipy`` documentation of the csr matrix at `scipy.sparse.csr_matrix <https://docs.scipy.org/doc/scipy/reference/generated/scipy.sparse.csr_matrix.html>`_ for additional details.
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.. code-block:: default
print(pk.data[:10])
print(pk.indices[:10])
print(pk.indptr[:10])
.. rst-class:: sphx-glr-script-out
.. code-block:: none
[ 0.57249304 0.56369167 -0.28624652 -0.28184583 -0.24789676 -0.24408565
-0.14312326 -0.14092292 0.77576289 -0.37033122]
[ 0 1 4 7 10 13 73 76 1 4]
[ 0 8 19 31 42 49 55 60 63 71]
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### Create a APDLMath Sparse Matrix from a SciPy Sparse CSR Matrix
Here, we transfer the ``scipy`` CSR matrix back to MAPDL. While
this example uses a matrix that was originally within MAPDL, you can
load any CSR matrix to MAPDL.
.. GENERATED FROM PYTHON SOURCE LINES 53-57
.. code-block:: default
my_mat = mm.matrix(pk, "my_mat", triu=True)
my_mat
.. rst-class:: sphx-glr-script-out
.. code-block:: none
Sparse APDLMath Matrix (126, 126)
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Check initial matrix ``k`` and ``my_mat`` are exactly the sames:
We compute the norm of the difference, should be zero
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.. code-block:: default
msub = k - my_mat
mm.norm(msub)
.. rst-class:: sphx-glr-script-out
.. code-block:: none
0.0
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CSR Representation in MAPDL
~~~~~~~~~~~~~~~~~~~~~~~~~~~
Printing the list of objects in the MAPDL space, we find:
- 2 SMAT objects, corresponding to the ``k``, ``MSub`` matrices,
- with encrypted names
- The ``my_mat`` SMAT object. Its size is zero, because the 3
- vectors are stored separately
- the 3 vectors of the CSR my_mat structure: ``MY_MAT_PTR``, ``MY_MAT_IND``
- and ``MY_MAT_DATA``
.. GENERATED FROM PYTHON SOURCE LINES 77-81
.. code-block:: default
mm.status()
.. rst-class:: sphx-glr-script-out
.. code-block:: none
APDLMATH PARAMETER STATUS- ( 6 PARAMETERS DEFINED)
Name Type Mem. (MB) Dims Workspace
KJQCBY SMAT 0.011 [126:126] 1
MY_MAT SMAT 0.000 [126:126] 1
SSNCEY SMAT 0.011 [126:126] 1
MY_MAT_DATA VEC 0.006 738 1
MY_MAT_IND VEC 0.001 127 1
MY_MAT_PTR VEC 0.003 738 1
.. GENERATED FROM PYTHON SOURCE LINES 82-87
MAPDL Python Matrix Correspondence
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To determine which MAPDL object corresponds to which Python object,
access the id property of the Python object.
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.. code-block:: default
print("name(k)=" + k.id)
print("name(my_mat)=" + my_mat.id)
print("name(msub)=" + msub.id)
.. rst-class:: sphx-glr-script-out
.. code-block:: none
name(k)=SSNCEY
name(my_mat)=my_mat
name(msub)=KJQCBY
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Stop mapdl
~~~~~~~~~~
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.. code-block:: default
mapdl.exit()
.. rst-class:: sphx-glr-timing
**Total running time of the script:** ( 0 minutes 0.813 seconds)
.. _sphx_glr_download_examples_gallery_examples_01-apdlmath-examples_scipy_sparse_matrix.py:
.. only:: html
.. container:: sphx-glr-footer sphx-glr-footer-example
.. container:: sphx-glr-download sphx-glr-download-python
:download:`Download Python source code: scipy_sparse_matrix.py <scipy_sparse_matrix.py>`
.. container:: sphx-glr-download sphx-glr-download-jupyter
:download:`Download Jupyter notebook: scipy_sparse_matrix.ipynb <scipy_sparse_matrix.ipynb>`
.. only:: html
.. rst-class:: sphx-glr-signature
`Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_