ImportGrid¶

class acoular.grids.ImportGrid¶

Bases: Grid

Load a 3D grid from an XML file.

This class is used to import a 3D grid defined in an XML file. The grid’s positions and subgrid names are parsed and stored for further processing.

file = Union(None, File(filter=['*.xml'], exists=True), desc='name of the xml file to import')¶: Name of the .xml-file from which to read the data.

subgrids = CArray(desc='names of subgrids for each point')¶: Names of subgrids for each point. This is an optional property, typically used when grids are divided into named subregions.

digest = Property(depends_on=['_gpos'])¶: A unique identifier for the grid, based on its properties. (read-only)

import_gpos()¶

Import the grid point locations and subgrid names from an XML file.

This method is automatically called whenever the file attribute changes.

Notes

The XML file should have elements with tag <pos>, where each <pos> element contains attributes for x, y, z, and optionally subgrid.

Examples

Generate the positional data of two microphone grids:

>>> import numpy as np
>>>
>>> # Grid 1: ten points aranged in a circle in the x-y plane at z=0
>>> args = 2 * np.pi * np.arange(10) / 10
>>> x1 = np.cos(args)
>>> y1 = np.sin(args)
>>> z1 = np.zeros_like(x1)
>>> grid1 = np.vstack([x1, y1, z1]).T
>>>
>>> # Grid 2: nine points aranged in a mesh grid the the x-y plane at z=1
>>> a = np.linspace(-1, 1, 3)
>>> x2, y2 = np.meshgrid(a, a)
>>> z2 = np.ones_like(x2)
>>> grid2 = np.vstack([x2, y2, z2])

Save the generated data in an XML file:

>>> import xml.etree.cElementTree as ET
>>>
>>> # Create the root element for the XML document
>>> root = ET.Element('root')
>>>
>>> # Loop over both grid 1 and grid 2, and create XML elements for each of their points
>>> for num, grid in enumerate([grid1, grid2]):
...     for x, y, z in grid:
...         # For each point in the grid, create a 'pos' XML element
...         ET.SubElement(root, 'pos', subgrid=str(num), x=str(x), y=str(y), z=str(z))
>>>
>>> # Create the final XML tree
>>> tree = ET.ElementTree(root)
>>>
>>> # Write the XML tree to a file named 'two_grids.xml'
>>> tree.write('two_grids.xml')

The two_grids.xml file will look like this:

<root>
    <pos subgrid="0" x="1.0" y="0.0" z="0.0" />
    <pos subgrid="0" x="0.8090169943749475" y="0.5877852522924731" z="0.0" />
    <pos subgrid="0" x="0.30901699437494745" y="0.9510565162951535" z="0.0" />
    <pos subgrid="0" x="-0.30901699437494734" y="0.9510565162951536" z="0.0" />
    <pos subgrid="0" x="-0.8090169943749473" y="0.5877852522924732" z="0.0" />
    <pos subgrid="0" x="-1.0" y="1.2246467991473532e-16" z="0.0" />
    <pos subgrid="0" x="-0.8090169943749475" y="-0.587785252292473" z="0.0" />
    <pos subgrid="0" x="-0.30901699437494756" y="-0.9510565162951535" z="0.0" />
    <pos subgrid="0" x="0.30901699437494723" y="-0.9510565162951536" z="0.0" />
    <pos subgrid="0" x="0.8090169943749473" y="-0.5877852522924732" z="0.0" />
    <pos subgrid="1" x="-1.0" y="0.0" z="1.0" />
    <pos subgrid="1" x="-1.0" y="0.0" z="1.0" />
    <pos subgrid="1" x="-1.0" y="0.0" z="1.0" />
    <pos subgrid="1" x="-1.0" y="-1.0" z="-1.0" />
    <pos subgrid="1" x="0.0" y="0.0" z="0.0" />
    <pos subgrid="1" x="1.0" y="1.0" z="1.0" />
    <pos subgrid="1" x="1.0" y="1.0" z="1.0" />
    <pos subgrid="1" x="1.0" y="1.0" z="1.0" />
    <pos subgrid="1" x="1.0" y="1.0" z="1.0" />
</root>

Importing the two_grids.xml file:

>>> import acoular as ac
>>>
>>> grids = ac.ImportGrid(file='two_grids.xml')
>>> grids.size
19
>>> grids.subgrids
array(['0', '0', '0', '0', '0', '0', '0', '0', '0', '0', '1', '1', '1',
       '1', '1', '1', '1', '1', '1'], dtype='<U1')
>>> grids.gpos.T
array([[ 1.00000000e+00,  0.00000000e+00,  0.00000000e+00],
       [ 8.09016994e-01,  5.87785252e-01,  0.00000000e+00],
       [ 3.09016994e-01,  9.51056516e-01,  0.00000000e+00],
       [-3.09016994e-01,  9.51056516e-01,  0.00000000e+00],
       [-8.09016994e-01,  5.87785252e-01,  0.00000000e+00],
       [-1.00000000e+00,  1.22464680e-16,  0.00000000e+00],
       [-8.09016994e-01, -5.87785252e-01,  0.00000000e+00],
       [-3.09016994e-01, -9.51056516e-01,  0.00000000e+00],
       [ 3.09016994e-01, -9.51056516e-01,  0.00000000e+00],
       [ 8.09016994e-01, -5.87785252e-01,  0.00000000e+00],
       [-1.00000000e+00,  0.00000000e+00,  1.00000000e+00],
       [-1.00000000e+00,  0.00000000e+00,  1.00000000e+00],
       [-1.00000000e+00,  0.00000000e+00,  1.00000000e+00],
       [-1.00000000e+00, -1.00000000e+00, -1.00000000e+00],
       [ 0.00000000e+00,  0.00000000e+00,  0.00000000e+00],
       [ 1.00000000e+00,  1.00000000e+00,  1.00000000e+00],
       [ 1.00000000e+00,  1.00000000e+00,  1.00000000e+00],
       [ 1.00000000e+00,  1.00000000e+00,  1.00000000e+00],
       [ 1.00000000e+00,  1.00000000e+00,  1.00000000e+00]])

Consider two XML files, grid1.xml and grid2.xml containing different grids.

>>> import acoular as ac
>>>
>>> grid = ac.ImportGrid(file='grid1.xml')
>>> grid.size
8
>>> grid.file = 'grid2.xml'
>>> grid.size
12

Acoular 25.04 documentation

ImportGrid

ImportGrid¶