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# numpy.meshgrid

`numpy.``meshgrid`(*xi, **kwargs)

  Return coordinate matrices from two or more coordinate vectors.

  Make N-D coordinate arrays for vectorized evaluations of N-D scalar/vector fields over N-D grids, given one-dimensional coordinate arrays x1, x2,..., xn.

  Parameters : | x1, x2,..., xn : array_like 1-D arrays representing the coordinates of a grid. indexing : {‘xy’, ‘ij’}, optional Cartesian (‘xy’, default) or matrix (‘ij’) indexing of output. See Notes for more details. sparse : bool, optional If True a sparse grid is returned in order to conserve memory. Default is False. copy : bool, optional If False, a view into the original arrays are returned in order to conserve memory. Default is True. Please note that `sparse=False, copy=False` will likely return non-contiguous arrays. Furthermore, more than one element of a broadcast array may refer to a single memory location. If you need to write to the arrays, make copies first.
  Returns : | X1, X2,..., XN : ndarray For vectors x1, x2,..., ‘xn’ with lengths `Ni=len(xi)` , return `(N1, N2, N3,...Nn)` shaped arrays if indexing=’ij’ or `(N2, N1, N3,...Nn)` shaped arrays if indexing=’xy’ with the elements of xi repeated to fill the matrix along the first dimension for x1, the second for x2 and so on.

  See also

  `index_tricks.mgrid`
    Construct a multi-dimensional “meshgrid” using indexing notation.
  `index_tricks.ogrid`
    Construct an open multi-dimensional “meshgrid” using indexing notation.

  Notes

  This function supports both indexing conventions through the indexing keyword argument. Giving the string ‘ij’ returns a meshgrid with matrix indexing, while ‘xy’ returns a meshgrid with Cartesian indexing. In the 2-D case with inputs of length M and N, the outputs are of shape (N, M) for ‘xy’ indexing and (M, N) for ‘ij’ indexing. In the 3-D case with inputs of length M, N and P, outputs are of shape (N, M, P) for ‘xy’ indexing and (M, N, P) for ‘ij’ indexing. The difference is illustrated by the following code snippet:

      xv, yv = meshgrid(x, y, sparse=False, indexing='ij')
      for i in range(nx):
          for j in range(ny):
              # treat xv[i,j], yv[i,j]

      xv, yv = meshgrid(x, y, sparse=False, indexing='xy')
      for i in range(nx):
          for j in range(ny):
              # treat xv[j,i], yv[j,i]

  Examples

      >>> nx, ny = (3, 2)
      >>> x = np.linspace(0, 1, nx)
      >>> y = np.linspace(0, 1, ny)
      >>> xv, yv = meshgrid(x, y)
      >>> xv
      array([[ 0. ,  0.5,  1. ],
             [ 0. ,  0.5,  1. ]])
      >>> yv
      array([[ 0.,  0.,  0.],
             [ 1.,  1.,  1.]])
      >>> xv, yv = meshgrid(x, y, sparse=True)  # make sparse output arrays
      >>> xv
      array([[ 0. ,  0.5,  1. ]])
      >>> yv
      array([[ 0.],
             [ 1.]])

  `meshgrid` is very useful to evaluate functions on a grid.

      >>> x = np.arange(-5, 5, 0.1)
      >>> y = np.arange(-5, 5, 0.1)
      >>> xx, yy = meshgrid(x, y, sparse=True)
      >>> z = np.sin(xx**2 + yy**2) / (xx**2 + yy**2)
      >>> h = plt.contourf(x,y,z)

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