Indexing routines

Generating index arrays

`dpnp.nonzero`	Return the indices of the elements that are non-zero.
`dpnp.where`	Return elements chosen from x or y depending on condition.
`dpnp.indices`	Return an array representing the indices of a grid.
`dpnp.ix_`	Construct an open mesh from multiple sequences.
`dpnp.ogrid`	Construct an open multi-dimensional "meshgrid".
`dpnp.ravel_multi_index`	Converts a tuple of index arrays into an array of flat indices, applying boundary modes to the multi-index.
`dpnp.unravel_index`	Converts array of flat indices into a tuple of coordinate arrays.
`dpnp.diag_indices`	Return the indices to access the main diagonal of an array.
`dpnp.diag_indices_from`	Return the indices to access the main diagonal of an n-dimensional array.
`dpnp.mask_indices`	Return the indices to access (n, n) arrays, given a masking function.
`dpnp.tril_indices`	Return the indices for the lower-triangle of an (n, m) array.
`dpnp.tril_indices_from`	Return the indices for the lower-triangle of arr.
`dpnp.triu_indices`	Return the indices for the upper-triangle of an (n, m) array.
`dpnp.triu_indices_from`	Return the indices for the lower-triangle of arr.

`dpnp.take`	Take elements from an array along an axis.
`dpnp.take_along_axis`	Take values from the input array by matching 1d index and data slices.
`dpnp.choose`	Construct an array from an index array and a set of arrays to choose from.
`dpnp.diag`	Extract a diagonal or construct a diagonal array.
`dpnp.diagonal`	Return specified diagonals.
`dpnp.select`	Return an array drawn from elements in choicelist, depending on conditions.

`dpnp.place`	Change elements of an array based on conditional and input values.
`dpnp.put`	Puts values of an array into another array along a given axis.
`dpnp.put_along_axis`	Put values into the destination array by matching 1d index and data slices.
`dpnp.putmask`	Changes elements of an array based on conditional and input values.
`dpnp.fill_diagonal`	Fill the main diagonal of the given array of any dimensionality.

`dpnp.ndindex`	An N-dimensional iterator object to index arrays.
`dpnp.flatiter`	Flat iterator object to iterate over arrays.