diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/README.md b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/README.md
new file mode 100644
index 000000000000..8ed485d38bd5
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/README.md
@@ -0,0 +1,136 @@
+
+
+# dcosqi
+
+> Initialize a workspace array for performing a quarter-wave cosine transform on a one-dimensional double-precision floating-point ndarray.
+
+
+
+
+
+
+
+
+
+## Usage
+
+```javascript
+var dcosqi = require( '@stdlib/fft/base/fftpack/ndarray/dcosqi' );
+```
+
+#### dcosqi( arrays )
+
+Initializes a workspace array for performing a quarter-wave cosine transform on a one-dimensional double-precision floating-point ndarray.
+
+```javascript
+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 w = new Float64Vector( ( 3*N ) + 34 );
+
+var out = dcosqi( [ w, len ] );
+// returns
+
+var bool = ( out === w );
+// returns true
+
+var cosineTable = slice( w, new Slice( 0, N ) );
+// returns [ ~0.98, ~0.92, ~0.83, ~0.7, ~0.56, ~0.38, ~0.2, ~0.0 ]
+
+var twiddleFactors = slice( w, new Slice( 2*N, 3*N ) );
+// returns [ ~0.707, ~0.707, 0, 0, 0, 0, 0, 0 ]
+
+var factors = slice( w, new Slice( 3*N, ( 3*N ) + 4 ) );
+// returns [ 8, 2, 2, 4 ]
+```
+
+The function has the following parameters:
+
+- **arrays**: array-like object containing the following ndarrays:
+
+ - a one-dimensional input ndarray.
+ - a zero-dimensional ndarray containing the length of the sequence to transform.
+
+
+
+
+
+
+
+## Notes
+
+- If provided an empty one-dimensional input ndarray, the function returns the output ndarray unchanged.
+
+
+
+
+
+
+
+## Examples
+
+
+
+```javascript
+var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var dcosqi = require( '@stdlib/fft/base/fftpack/ndarray/dcosqi' );
+
+var N = 8;
+
+var w = new Float64Vector( ( 3*N ) + 34 );
+console.log( ndarray2array( w ) );
+
+var len = scalar2ndarray( N, {
+ 'dtype': 'int32'
+});
+
+var out = dcosqi( [ w, len ] );
+console.log( ndarray2array( out ) );
+```
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/benchmark/benchmark.js b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/benchmark/benchmark.js
new file mode 100644
index 000000000000..32255b09f92c
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/benchmark/benchmark.js
@@ -0,0 +1,106 @@
+/**
+* @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 bench = require( '@stdlib/bench' );
+var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
+var format = require( '@stdlib/string/format' );
+var pkg = require( './../package.json' ).name;
+var dcosqi = require( './../lib' );
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} N - sequence length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( N ) {
+ var len = scalar2ndarray( N, {
+ 'dtype': 'int32'
+ });
+ var w = new Float64Vector( ( 3*N ) + 34 );
+ return benchmark;
+
+ /**
+ * Benchmark function.
+ *
+ * @private
+ * @param {Benchmark} b - benchmark instance
+ */
+ function benchmark( b ) {
+ var v;
+ var i;
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ v = dcosqi( [ w, len ] );
+ if ( typeof v !== 'object' ) {
+ b.fail( 'should return an ndarray' );
+ }
+ }
+ b.toc();
+ if ( isnan( v.get( 2*N ) ) ) {
+ b.fail( 'should not return NaN' );
+ }
+ b.pass( 'benchmark finished' );
+ b.end();
+ }
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+ var lengths;
+ var N;
+ var f;
+ var i;
+
+ lengths = [
+ 8,
+ 16,
+ 32,
+ 64,
+ 128,
+ 256,
+ 512,
+ 1024
+ ];
+
+ for ( i = 0; i < lengths.length; i++ ) {
+ N = lengths[ i ];
+ f = createBenchmark( N );
+ bench( format( '%s:N=%d', pkg, N ), f );
+ }
+}
+
+main();
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/repl.txt b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/repl.txt
new file mode 100644
index 000000000000..7f0b975d8761
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/repl.txt
@@ -0,0 +1,44 @@
+
+{{alias}}( arrays )
+ Initializes a workspace array for performing a quarter-wave cosine
+ transform on a one-dimensional double-precision floating-point ndarray.
+
+ If provided an empty input ndarray, the function returns the output ndarray
+ unchanged.
+
+ Parameters
+ ----------
+ arrays: ArrayLikeObject
+ Array-like object containing the following ndarrays:
+
+ - a one-dimensional input ndarray.
+ - a zero-dimensional ndarray containing the length of the sequence to
+ transform.
+
+ Returns
+ -------
+ out: ndarray
+ Output ndarray.
+
+ Examples
+ --------
+ > var N = 8;
+ > var w = new {{alias:@stdlib/ndarray/vector/float64}}( ( 3*N ) + 34 );
+ > var len = {{alias:@stdlib/ndarray/from-scalar}}( N, { 'dtype': 'int32' });
+ > var out = {{alias}}( [ w, len ] )
+
+ > var bool = ( out === w )
+ true
+ > var s = new {{alias:@stdlib/slice/ctor}}( 0, N );
+ > var cosineTable = {{alias:@stdlib/ndarray/slice}}( w, s )
+ [ ~0.98, ~0.92, ~0.83, ~0.7, ~0.56, ~0.38, ~0.2, ~0.0 ]
+ > s = new {{alias:@stdlib/slice/ctor}}( 2*N, 3*N );
+ > var twiddleFactors = {{alias:@stdlib/ndarray/slice}}( w, s )
+ [ ~0.707, ~0.707, 0, 0, 0, 0, 0, 0 ]
+ > s = new {{alias:@stdlib/slice/ctor}}( 3*N, ( 3*N ) + 4 );
+ > var factors = {{alias:@stdlib/ndarray/slice}}( w, s )
+ [ 8, 2, 2, 4 ]
+
+ See Also
+ --------
+
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/types/index.d.ts b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/types/index.d.ts
new file mode 100644
index 000000000000..8d555cbbe131
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/types/index.d.ts
@@ -0,0 +1,71 @@
+/*
+* @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.
+*/
+
+// TypeScript Version: 4.1
+
+///
+
+import { typedndarray, float64ndarray } from '@stdlib/types/ndarray';
+
+/**
+* Initializes a workspace array for performing a quarter-wave cosine transform on a one-dimensional double-precision floating-point ndarray.
+*
+* ## Notes
+*
+* - The function expects the following ndarrays:
+*
+* - a one-dimensional input ndarray.
+* - a zero-dimensional ndarray containing the length of the sequence to transform.
+*
+* @param arrays - array-like object containing ndarrays
+* @returns 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 w = new Float64Vector( ( 3*N ) + 34 );
+*
+* var out = dcosqi( [ w, len ] );
+* // returns
+*
+* var bool = ( out === w );
+* // returns true
+*
+* var cosineTable = slice( w, new Slice( 0, N ) );
+* // returns [ ~0.98, ~0.92, ~0.83, ~0.7, ~0.56, ~0.38, ~0.2, ~0.0 ]
+*
+* var twiddleFactors = slice( w, new Slice( 2*N, 3*N ) );
+* // returns [ ~0.707, ~0.707, 0, 0, 0, 0, 0, 0 ]
+*
+* var factors = slice( w, new Slice( 3*N, ( 3*N ) + 4 ) );
+* // returns [ 8, 2, 2, 4 ]
+*/
+declare function dcosqi( arrays: [ float64ndarray, typedndarray ] ): float64ndarray;
+
+
+// EXPORTS //
+
+export = dcosqi;
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/types/test.ts b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/types/test.ts
new file mode 100644
index 000000000000..69f33f995cb6
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/docs/types/test.ts
@@ -0,0 +1,63 @@
+/*
+* @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.
+*/
+
+/* eslint-disable space-in-parens */
+
+import zeros = require( '@stdlib/ndarray/zeros' );
+import dcosqi = require( './index' );
+
+
+// TESTS //
+
+// The function returns an ndarray...
+{
+ const w = zeros( [ 10 ], {
+ 'dtype': 'float64'
+ });
+ const N = zeros( [], {
+ 'dtype': 'int32'
+ });
+
+ dcosqi( [ w, N ] ); // $ExpectType float64ndarray
+}
+
+// The compiler throws an error if the function is provided a first argument which is not an array of ndarrays...
+{
+ dcosqi( '10' ); // $ExpectError
+ dcosqi( 10 ); // $ExpectError
+ dcosqi( true ); // $ExpectError
+ dcosqi( false ); // $ExpectError
+ dcosqi( null ); // $ExpectError
+ dcosqi( undefined ); // $ExpectError
+ dcosqi( [] ); // $ExpectError
+ dcosqi( {} ); // $ExpectError
+ dcosqi( ( x: number ): number => x ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided an unsupported number of arguments...
+{
+ const w = zeros( [ 10 ], {
+ 'dtype': 'float64'
+ });
+ const N = zeros( [], {
+ 'dtype': 'int32'
+ });
+
+ dcosqi(); // $ExpectError
+ dcosqi( [ w, N ], {} ); // $ExpectError
+}
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/examples/index.js b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/examples/index.js
new file mode 100644
index 000000000000..56a48190a4e3
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/examples/index.js
@@ -0,0 +1,36 @@
+/**
+* @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';
+
+var Float64Vector = require( '@stdlib/ndarray/vector/float64' );
+var scalar2ndarray = require( '@stdlib/ndarray/from-scalar' );
+var ndarray2array = require( '@stdlib/ndarray/to-array' );
+var dcosqi = require( './../lib' );
+
+var N = 8;
+
+var w = new Float64Vector( ( 3*N ) + 34 );
+console.log( ndarray2array( w ) );
+
+var len = scalar2ndarray( N, {
+ 'dtype': 'int32'
+});
+
+var out = dcosqi( [ w, len ] );
+console.log( ndarray2array( out ) );
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/lib/index.js b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/lib/index.js
new file mode 100644
index 000000000000..dc780e7a6355
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/lib/index.js
@@ -0,0 +1,63 @@
+/**
+* @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';
+
+/**
+* Initialize a workspace array for performing a quarter-wave cosine transform on a one-dimensional double-precision floating-point ndarray.
+*
+* @module @stdlib/fft/base/fftpack/ndarray/dcosqi
+*
+* @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 dcosqi = require( '@stdlib/fft/base/fftpack/ndarray/dcosqi' );
+*
+* var N = 8;
+* var len = scalar2ndarray( N, {
+* 'dtype': 'int32'
+* });
+*
+* var w = new Float64Vector( ( 3*N ) + 34 );
+*
+* var out = dcosqi( [ w, len ] );
+* // returns
+*
+* var bool = ( out === w );
+* // returns true
+*
+* var cosineTable = slice( w, new Slice( 0, N ) );
+* // returns [ ~0.98, ~0.92, ~0.83, ~0.7, ~0.56, ~0.38, ~0.2, ~0.0 ]
+*
+* var twiddleFactors = slice( w, new Slice( 2*N, 3*N ) );
+* // returns [ ~0.707, ~0.707, 0, 0, 0, 0, 0, 0 ]
+*
+* var factors = slice( w, new Slice( 3*N, ( 3*N ) + 4 ) );
+* // returns [ 8, 2, 2, 4 ]
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/lib/main.js b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/lib/main.js
new file mode 100644
index 000000000000..35e048753056
--- /dev/null
+++ b/lib/node_modules/@stdlib/fft/base/fftpack/ndarray/dcosqi/lib/main.js
@@ -0,0 +1,86 @@
+/**
+* @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/cosqi' );
+var ndarraylike2scalar = require( '@stdlib/ndarray/base/ndarraylike2scalar' );
+
+
+// MAIN //
+
+/**
+* Initializes a workspace array for performing a quarter-wave cosine transform on a one-dimensional double-precision floating-point ndarray.
+*
+* ## Notes
+*
+* - The function expects the following ndarrays:
+*
+* - a one-dimensional input ndarray.
+* - a zero-dimensional ndarray containing the length of the sequence to transform.
+*
+* @param {ArrayLikeObject