Usage

1var nextCartesianIndex = require( '@stdlib/ndarray-base-next-cartesian-index' );

nextCartesianIndex( shape, order, idx, dim )

Returns the next Cartesian index (i.e., set of subscripts/dimension indices).

1var idx = nextCartesianIndex( [ 2, 2, 2 ], 'row-major', [ 0, 0, 1 ], -1 );
2// returns [ 0, 1, 0 ]

The function accepts the following arguments:

• shape: array shape.
• order: index iteration order. Must be either row-major (C-style) or column-major (Fortran-style).
• idx: current dimension indices.
• dim: index of the dimension from which to start incrementing (inclusive).

The order parameter specifies the index iteration order. When order is row-major, the last indices change fastest, and, when the order is column-major, the first indices change fastest.

1var idx = nextCartesianIndex( [ 2, 2, 2 ], 'column-major', [ 0, 1, 0 ], 0 );
2// returns [ 1, 1, 0 ]

The dim parameter controls which dimensions are incremented. When order is row-major, if dim equals shape.length-1 (or equivalently -1), the function increments over all dimensions from right-to-left (last-to-first). Similarly, when order is column-major, if dim equals 0, the function increments over all dimensions from left-to-right (first-to-last). To restrict which dimensions can be incremented, set dim to a value other than the respective end. For example,

1// Increment starting from the second-to-last dimension:
2var idx = nextCartesianIndex( [ 2, 2, 2 ], 'row-major', [ 0, 0, 0 ], -2 );
3// returns [ 0, 1, 0 ]
4
5idx = nextCartesianIndex( [ 2, 2, 2 ], 'row-major', idx, -2 );
6// returns [ 1, 0, 0 ]
7
8idx = nextCartesianIndex( [ 2, 2, 2 ], 'row-major', idx, -2 );
9// returns [ 1, 1, 0 ]

nextCartesianIndex.assign( shape, order, idx, dim, out )

Returns the next Cartesian index (i.e., set of subscripts/dimension indices) and assigns results to a provided output array.

1var out = [ 0, 0, 0 ];
2var idx = nextCartesianIndex.assign( [ 2, 2, 2 ], 'row-major', [ 0, 0, 1 ], -1, out );
3// returns [ 0, 1, 0 ]
4
5var bool = ( out === idx );
6// returns true

The function accepts the following arguments:

• shape: array shape.
• order: index iteration order. Must be either row-major (C-style) or column-major (Fortran-style).
• idx: current dimension indices.
• dim: index of the dimension from which to start incrementing (inclusive).
• out: output array.