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edge_indices

edge_indices(n, closed=False)

Returns matrix of edge indices

Given an ordered polyline, this returns the edge indeces in a similar way to how the face indeces of a triangle mesh are given.

Parameters:

Name Type Description Default
n int

Number of vertices in polyline

 required
closed boolean, optional (default False)

Matrix of triangle indices

 False

Returns:

Name Type Description
EC numpy int array

Matrix of edge indeces

See Also

edges.

Notes

Examples:

# Ordered in V
from gpytoolbox import edge_indices
EC = edge_indices(V.shape[0],closed=False)
# Now we can use EC as the face indices for input to other functions
Source code in src/gpytoolbox/edge_indices.py 
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def edge_indices(n,closed=False):
    """Returns matrix of edge indices

    Given an ordered polyline, this returns the edge indeces in a similar way to how the face indeces of a triangle mesh are given.

    Parameters
    ----------
    n : int
        Number of vertices in polyline
    closed : boolean, optional (default False)
        Matrix of triangle indices

    Returns
    -------
    EC : numpy int array
        Matrix of edge indeces

    See Also
    --------
    edges.

    Notes
    -----


    Examples
    --------
    ```python
    # Ordered in V
    from gpytoolbox import edge_indices
    EC = edge_indices(V.shape[0],closed=False)
    # Now we can use EC as the face indices for input to other functions
    ```
    """

    # Note: the "order='F'" in all the reshapes is to mimic scanning order from
    # Matlab, otherwise it does the reverse order (rows first)
    if closed:
        return np.reshape(np.concatenate((np.linspace(0,n-1,n,dtype=int),
             np.linspace(1,n-1,n-1,dtype=int),np.array([0]))),(-1, 2),order='F')
    else:
        return np.reshape(np.concatenate((np.linspace(0,n-2,n-1,dtype=int),
             np.linspace(1,n-1,n-1,dtype=int))),(-1, 2),order='F')