dsortins
Sort a double-precision floating-point strided array using insertion sort.
Usage
var dsortins = require( '@stdlib/blas/ext/base/dsortins' );
dsortins( N, order, x, stride )
Sorts a double-precision floating-point strided array x
using insertion sort.
var Float64Array = require( '@stdlib/array/float64' );
var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0 ] );
dsortins( x.length, 1.0, x, 1 );
// x => <Float64Array>[ -4.0, -2.0, 1.0, 3.0 ]
The function has the following parameters:
- N: number of indexed elements.
- order: sort order. If
order < 0.0
, the input strided array is sorted in decreasing order. Iforder > 0.0
, the input strided array is sorted in increasing order. Iforder == 0.0
, the input strided array is left unchanged. - x: input
Float64Array
. - stride: index increment.
The N
and stride
parameters determine which elements in x
are accessed at runtime. For example, to sort every other element
var Float64Array = require( '@stdlib/array/float64' );
var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0 ] );
dsortins( 2, -1.0, x, 2 );
// x => <Float64Array>[ 3.0, -2.0, 1.0, -4.0 ]
Note that indexing is relative to the first index. To introduce an offset, use typed array
views.
var Float64Array = require( '@stdlib/array/float64' );
// Initial array...
var x0 = new Float64Array( [ 1.0, 2.0, 3.0, 4.0 ] );
// Create an offset view...
var x1 = new Float64Array( x0.buffer, x0.BYTES_PER_ELEMENT*1 ); // start at 2nd element
// Sort every other element...
dsortins( 2, -1.0, x1, 2 );
// x0 => <Float64Array>[ 1.0, 4.0, 3.0, 2.0 ]
dsortins.ndarray( N, order, x, stride, offset )
Sorts a double-precision floating-point strided array x
using insertion sort and alternative indexing semantics.
var Float64Array = require( '@stdlib/array/float64' );
var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0 ] );
dsortins.ndarray( x.length, 1.0, x, 1, 0 );
// x => <Float64Array>[ -4.0, -2.0, 1.0, 3.0 ]
The function has the following additional parameters:
- offset: starting index.
While typed array
views mandate a view offset based on the underlying buffer
, the offset
parameter supports indexing semantics based on a starting index. For example, to access only the last three elements of x
var Float64Array = require( '@stdlib/array/float64' );
var x = new Float64Array( [ 1.0, -2.0, 3.0, -4.0, 5.0, -6.0 ] );
dsortins.ndarray( 3, 1.0, x, 1, x.length-3 );
// x => <Float64Array>[ 1.0, -2.0, 3.0, -6.0, -4.0, 5.0 ]
Notes
- If
N <= 0
ororder == 0.0
, both functions returnx
unchanged. - The algorithm distinguishes between
-0
and+0
. When sorted in increasing order,-0
is sorted before+0
. When sorted in decreasing order,-0
is sorted after+0
. - The algorithm sorts
NaN
values to the end. When sorted in increasing order,NaN
values are sorted last. When sorted in decreasing order,NaN
values are sorted first. - The algorithm has space complexity
O(1)
and worst case time complexityO(N^2)
. - The algorithm is efficient for small strided arrays (typically
N <= 20
) and is particularly efficient for sorting strided arrays which are already substantially sorted. - The algorithm is stable, meaning that the algorithm does not change the order of strided array elements which are equal or equivalent (e.g.,
NaN
values). - The input strided array is sorted in-place (i.e., the input strided array is mutated).
Examples
var filledarrayBy = require( '@stdlib/array/filled-by' );
var uniform = require( '@stdlib/random/base/uniform' ).factory;
var dsortins = require( '@stdlib/blas/ext/base/dsortins' );
var x = filledarrayBy( 100, 'float64', uniform( -100.0, 100.0 ) );
console.log( x );
dsortins( x.length, -1.0, x, -1 );
console.log( x );