refactor: use base utility to resolve the next Cartesian index

Author: kgryte

lib/node_modules/@stdlib/ndarray/iter/columns/lib/main.js

@@ -29,39 +29,11 @@ var iteratorSymbol = require( '@stdlib/symbol/iterator' );
 var zeros = require( '@stdlib/array/base/zeros' );
 var numel = require( '@stdlib/ndarray/base/numel' );
 var slice = require( '@stdlib/ndarray/base/slice' );
+var nextCartesianIndex = require( '@stdlib/ndarray/base/next-cartesian-index' ).assign;
 var MultiSlice = require( '@stdlib/slice/multi' );
 var format = require( '@stdlib/string/format' );
 
 
-// FUNCTIONS //
-
-/**
-* Increments stack indices.
-*
-* @private
-* @param {NonNegativeInteger} ndims - number of dimensions
-* @param {NonNegativeIntegerArray} shape - array shape
-* @param {NonNegativeIntegerArray} idx - current indices
-* @returns {NonNegativeIntegerArray} updated indices
-*/
-function incrementIndices( ndims, shape, idx ) {
-	var i;
-	var j;
-
-	// Search for the first dimension in which we don't have to "carry the one"...
-	for ( i = ndims-3; i >= 0; i-- ) {
-		j = ( idx[ i ] + 1 ) % shape[ i ];
-		idx[ i ] = j;
-
-		// If the current index value is greater than zero, we can continue iterating within the current sub-array...
-		if ( j > 0 ) {
-			break;
-		}
-	}
-	return idx;
-}
-
-
 // MAIN //
 
 /**
@@ -136,7 +108,7 @@ function nditerColumns( x ) {
 			opts.writable = !options.readonly;
 		}
 	}
-	// Retrieve the input array shape:
+	// Retrieve input array meta data:
 	shape = x.shape;
 	ndims = shape.length;
 
@@ -197,7 +169,7 @@ function nditerColumns( x ) {
 		idx[ dim ] = j;
 		if ( j === 0 ) {
 			// If we've iterated over all the columns in the current matrix, move on to the next matrix in the stack:
-			incrementIndices( ndims, shape, idx );
+			idx = nextCartesianIndex( shape, 'row-major', idx, dim-2, idx );
 		}
 		// Return the next column slice:
 		return {