@stdlib/ndarray-base-offset
Version:
Return the index offset specifying the underlying buffer index of the first iterated ndarray element.
64 lines (53 loc) • 1.38 kB
JavaScript
/**
* @license Apache-2.0
*
* Copyright (c) 2023 The Stdlib Authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
;
// MODULES //
var strides2offset = require( '@stdlib/ndarray-base-strides2offset' );
// MAIN //
/**
* Returns the index offset specifying the underlying buffer index of the first iterated ndarray element.
*
* @param {ndarrayLike} x - input ndarray
* @returns {NonNegativeInteger} index offset
*
* @example
* var zeros = require( '@stdlib/ndarray-zeros' );
*
* var n = offset( zeros( [ 3, 3, 3 ] ) );
* // returns 0
*/
function offset( x ) {
var st;
var sh;
var o;
o = x.offset;
if ( typeof o === 'number' ) {
return o;
}
sh = x.shape;
if ( sh.length === 0 ) {
return 0;
}
st = x.strides;
if ( typeof st !== 'object' || st === null ) {
return 0;
}
return strides2offset( sh, st );
}
// EXPORTS //
module.exports = offset;