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* @license Apache-2.0
*
* Copyright (c) 2026 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.
*/
'use strict';
// MODULES //
var getStride = require( '@stdlib/ndarray/base/stride' );
var getOffset = require( '@stdlib/ndarray/base/offset' );
var getData = require( '@stdlib/ndarray/base/data-buffer' );
var strided = require( '@stdlib/fft/base/fftpack/rffti' );
var ndarraylike2scalar = require( '@stdlib/ndarray/base/ndarraylike2scalar' );
// MAIN //
/**
* Initializes a workspace array for performing a real-valued Fourier transform on a one-dimensional ndarray.
*
* ## Notes
*
* - The function expects the following ndarrays:
*
* - a zero-dimensional ndarray containing the length of the sequence to transform.
* - a one-dimensional input ndarray.
*
* @param {ArrayLikeObject<Object>} arrays - array-like object containing ndarrays
* @returns {ndarrayLike} output ndarray
*
* @example
* var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
* var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
* var Slice = require( '@stdlib/slice/ctor' );
* var slice = require( '@stdlib/ndarray/slice' );
*
* var N = 8;
* var len = scalar2ndarray( N, {
* 'dtype': 'int32'
* });
*
* var workspace = new Float64Vector( ( 2*N ) + 34 );
*
* var out = rffti( [ len, workspace ] );
* // returns <ndarray>
*
* var bool = ( out === workspace );
* // returns true
*
* var twiddleFactors = slice( workspace, new Slice( N, 2*N ) );
* // returns <ndarray>[ ~0.707, ~0.707, 0, 0, 0, 0, 0, 0 ]
*
* var factors = slice( workspace, new Slice( 2*N, ( 2*N ) + 4 ) );
* // returns <ndarray>[ 8, 2, 2, 4 ]
*/
function rffti( arrays ) {
var workspace;
var N;
N = ndarraylike2scalar( arrays[ 0 ] );
workspace = arrays[ 1 ];
strided( N, getData( workspace ), getStride( workspace, 0 ), getOffset( workspace ) ); // eslint-disable-line max-len
return workspace;
}
// EXPORTS //
module.exports = rffti;
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