diff --git a/CHANGELOG.md b/CHANGELOG.md
index 9e2b371f..29b552a9 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -461,6 +461,40 @@ This release closes the following issue:
+
+
+#### [@stdlib/array/base/unary3d-by](https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/base/unary3d-by)
+
+
+
+
+
+##### Features
+
+- [`70aaa8c`](https://github.com/stdlib-js/stdlib/commit/70aaa8ca5c7fa401321769137542c4001f529536) - add `array/base/unary3d-by` [(#3219)](https://github.com/stdlib-js/stdlib/pull/3219)
+
+
+
+
+
+
+
+##### Closed Issues
+
+This release closes the following issue:
+
+[#3173](https://github.com/stdlib-js/stdlib/issues/3173)
+
+
+
+
+
+
+
+
+
+
+
#### [@stdlib/array/bool](https://github.com/stdlib-js/stdlib/tree/develop/lib/node_modules/%40stdlib/array/bool)
@@ -593,9 +627,9 @@ A total of 12 issues were closed in this release:
### Closed Issues
-A total of 20 issues were closed in this release:
+A total of 21 issues were closed in this release:
-[#3135](https://github.com/stdlib-js/stdlib/issues/3135), [#3138](https://github.com/stdlib-js/stdlib/issues/3138), [#3140](https://github.com/stdlib-js/stdlib/issues/3140), [#3145](https://github.com/stdlib-js/stdlib/issues/3145), [#3146](https://github.com/stdlib-js/stdlib/issues/3146), [#3147](https://github.com/stdlib-js/stdlib/issues/3147), [#3149](https://github.com/stdlib-js/stdlib/issues/3149), [#3150](https://github.com/stdlib-js/stdlib/issues/3150), [#3151](https://github.com/stdlib-js/stdlib/issues/3151), [#3152](https://github.com/stdlib-js/stdlib/issues/3152), [#3155](https://github.com/stdlib-js/stdlib/issues/3155), [#3162](https://github.com/stdlib-js/stdlib/issues/3162), [#3164](https://github.com/stdlib-js/stdlib/issues/3164), [#3165](https://github.com/stdlib-js/stdlib/issues/3165), [#3166](https://github.com/stdlib-js/stdlib/issues/3166), [#3176](https://github.com/stdlib-js/stdlib/issues/3176), [#3177](https://github.com/stdlib-js/stdlib/issues/3177), [#3178](https://github.com/stdlib-js/stdlib/issues/3178), [#3179](https://github.com/stdlib-js/stdlib/issues/3179), [#3180](https://github.com/stdlib-js/stdlib/issues/3180)
+[#3135](https://github.com/stdlib-js/stdlib/issues/3135), [#3138](https://github.com/stdlib-js/stdlib/issues/3138), [#3140](https://github.com/stdlib-js/stdlib/issues/3140), [#3145](https://github.com/stdlib-js/stdlib/issues/3145), [#3146](https://github.com/stdlib-js/stdlib/issues/3146), [#3147](https://github.com/stdlib-js/stdlib/issues/3147), [#3149](https://github.com/stdlib-js/stdlib/issues/3149), [#3150](https://github.com/stdlib-js/stdlib/issues/3150), [#3151](https://github.com/stdlib-js/stdlib/issues/3151), [#3152](https://github.com/stdlib-js/stdlib/issues/3152), [#3155](https://github.com/stdlib-js/stdlib/issues/3155), [#3162](https://github.com/stdlib-js/stdlib/issues/3162), [#3164](https://github.com/stdlib-js/stdlib/issues/3164), [#3165](https://github.com/stdlib-js/stdlib/issues/3165), [#3166](https://github.com/stdlib-js/stdlib/issues/3166), [#3173](https://github.com/stdlib-js/stdlib/issues/3173), [#3176](https://github.com/stdlib-js/stdlib/issues/3176), [#3177](https://github.com/stdlib-js/stdlib/issues/3177), [#3178](https://github.com/stdlib-js/stdlib/issues/3178), [#3179](https://github.com/stdlib-js/stdlib/issues/3179), [#3180](https://github.com/stdlib-js/stdlib/issues/3180)
@@ -605,7 +639,7 @@ A total of 20 issues were closed in this release:
### Contributors
-A total of 10 people contributed to this release. Thank you to the following contributors:
+A total of 11 people contributed to this release. Thank you to the following contributors:
- Aayush Khanna
- Abhijit Raut
@@ -614,6 +648,7 @@ A total of 10 people contributed to this release. Thank you to the following con
- Athan Reines
- Kshitij-Dale
- Muhammad Haris
+- Neeraj Pathak
- Philipp Burckhardt
- Rylan Yang
- Vinit Pandit
@@ -628,6 +663,7 @@ A total of 10 people contributed to this release. Thank you to the following con
+- [`70aaa8c`](https://github.com/stdlib-js/stdlib/commit/70aaa8ca5c7fa401321769137542c4001f529536) - **feat:** add `array/base/unary3d-by` [(#3219)](https://github.com/stdlib-js/stdlib/pull/3219) _(by Neeraj Pathak, Athan Reines, stdlib-bot)_
- [`982980c`](https://github.com/stdlib-js/stdlib/commit/982980c5e719d7ab8f227b9aea9507ab45b15957) - **feat:** add `array/base/broadcasted-ternary5d` [(#3251)](https://github.com/stdlib-js/stdlib/pull/3251) _(by Vinit Pandit, Athan Reines)_
- [`bf5643f`](https://github.com/stdlib-js/stdlib/commit/bf5643fb1a3f32a60903d8e210f71571e609119f) - **docs:** update related packages sections [(#3404)](https://github.com/stdlib-js/stdlib/pull/3404) _(by stdlib-bot)_
- [`ac06419`](https://github.com/stdlib-js/stdlib/commit/ac06419c2a8358dfd80818823f571077eb58958e) - **docs:** update related packages sections [(#3387)](https://github.com/stdlib-js/stdlib/pull/3387) _(by stdlib-bot)_
diff --git a/base/unary3d-by/README.md b/base/unary3d-by/README.md
new file mode 100644
index 00000000..081c246f
--- /dev/null
+++ b/base/unary3d-by/README.md
@@ -0,0 +1,180 @@
+
+
+# unary3dBy
+
+> Apply a unary function to each element retrieved from a three-dimensional nested input array according to a callback function and assign results to elements in a three-dimensional nested output array.
+
+
+
+
+
+
+
+## Usage
+
+```javascript
+var unary3dBy = require( '@stdlib/array/base/unary3d-by' );
+```
+
+#### unary3dBy( arrays, shape, fcn, clbk\[, thisArg] )
+
+Applies a unary function to each element retrieved from a three-dimensional nested input array according to a callback function and assigns results to elements in a three-dimensional nested output array.
+
+```javascript
+var abs = require( '@stdlib/math/base/special/abs' );
+
+function accessor( v ) {
+ return v * 2.0;
+}
+
+var x = [ [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ];
+var shape = [ 1, 2, 2 ];
+
+unary3dBy( [ x, x ], shape, abs, accessor );
+// x => [ [ [ 2.0, 4.0 ], [ 6.0, 8.0 ] ] ]
+```
+
+The function accepts the following arguments:
+
+- **arrays**: array-like object containing one input nested array and one output nested array.
+- **shape**: array shape.
+- **fcn**: unary function to apply to callback return values.
+- **clbk**: callback function.
+- **thisArg**: callback function execution context (optional).
+
+The invoked callback function is provided the following arguments:
+
+- **value**: array element.
+- **indices**: current array element indices.
+- **arrays**: input and output arrays.
+
+To set the callback execution context, provide a `thisArg`.
+
+
+
+```javascript
+var abs = require( '@stdlib/math/base/special/abs' );
+
+function accessor( v ) {
+ this.count += 1;
+ return v * 2.0;
+}
+
+var context = {
+ 'count': 0
+};
+
+var x = [ [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ];
+var y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+var shape = [ 1, 2, 2 ];
+
+unary3dBy( [ x, y ], shape, abs, accessor, context );
+// y => [ [ [ 2.0, 4.0 ], [ 6.0, 8.0 ] ] ]
+
+var cnt = context.count;
+// returns 4
+```
+
+
+
+
+
+
+
+## Notes
+
+- If a provided callback function does not return any value (or equivalently, explicitly returns `undefined`), the value is **ignored**.
+
+ ```javascript
+ var abs = require( '@stdlib/math/base/special/abs' );
+
+ function accessor() {
+ // No-op...
+ }
+
+ var x = [ [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ];
+ var y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+ var shape = [ 1, 2, 2 ];
+
+ unary3dBy( [ x, y ], shape, abs, accessor );
+ // y => [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ]
+ ```
+
+- The function assumes that the input and output arrays have the same shape.
+
+
+
+
+
+
+
+## Examples
+
+
+
+```javascript
+var discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
+var bernoulli = require( '@stdlib/random/base/bernoulli' );
+var filled3dBy = require( '@stdlib/array/base/filled3d-by' );
+var zeros3d = require( '@stdlib/array/base/zeros3d' );
+var abs = require( '@stdlib/math/base/special/abs' );
+var unary3dBy = require( '@stdlib/array/base/unary3d-by' );
+
+function accessor( v ) {
+ // Randomly determine whether a value should be considered "missing":
+ return ( bernoulli( 0.5 ) > 0 ) ? v : void 0;
+}
+
+var shape = [ 3, 3, 3 ];
+
+var x = filled3dBy( shape, discreteUniform( -100, 100 ) );
+console.log( x );
+
+var y = zeros3d( shape );
+console.log( y );
+
+unary3dBy( [ x, y ], shape, abs, accessor );
+console.log( y );
+```
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
+
diff --git a/base/unary3d-by/benchmark/benchmark.js b/base/unary3d-by/benchmark/benchmark.js
new file mode 100644
index 00000000..34a35470
--- /dev/null
+++ b/base/unary3d-by/benchmark/benchmark.js
@@ -0,0 +1,130 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 uniform = require( '@stdlib/random/base/uniform' ).factory;
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var floor = require( '@stdlib/math/base/special/floor' );
+var identity = require( '@stdlib/math/base/special/identity' );
+var filled3dBy = require( './../../../base/filled3d-by' );
+var zeros3d = require( './../../../base/zeros3d' );
+var numel = require( '@stdlib/ndarray/base/numel' );
+var pkg = require( './../package.json' ).name;
+var unary3dBy = require( './../lib' );
+
+
+// FUNCTIONS //
+
+/**
+* Accessor function.
+*
+* @private
+* @param {number} value - array element
+* @returns {number} accessed value
+*/
+function accessor( value ) {
+ return value;
+}
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveIntegerArray} shape - array shape
+* @returns {Function} benchmark function
+*/
+function createBenchmark( shape ) {
+ var arrays;
+ var x;
+ var y;
+
+ x = filled3dBy( shape, uniform( -100.0, 100.0 ) );
+ y = zeros3d( shape );
+
+ arrays = [ x, y ];
+
+ return benchmark;
+
+ /**
+ * Benchmark function.
+ *
+ * @private
+ * @param {Benchmark} b - benchmark instance
+ */
+ function benchmark( b ) {
+ var i0;
+ var i1;
+ var i2;
+ var i;
+
+ b.tic();
+ for ( i = 0; i < b.iterations; i++ ) {
+ unary3dBy( arrays, shape, identity, accessor );
+ i2 = i % shape[ 0 ];
+ i1 = i % shape[ 1 ];
+ i0 = i % shape[ 2 ];
+ if ( isnan( arrays[ 1 ][ i2 ][ i1 ][ i0 ] ) ) {
+ b.fail( 'should not return NaN' );
+ }
+ }
+ b.toc();
+
+ i2 = i % shape[ 0 ];
+ i1 = i % shape[ 1 ];
+ i0 = i % shape[ 2 ];
+ if ( isnan( arrays[ 1 ][ i2 ][ i1 ][ i0 ] ) ) {
+ b.fail( 'should not return NaN' );
+ }
+ b.pass( 'benchmark finished' );
+ b.end();
+ }
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+ var min;
+ var max;
+ var sh;
+ var N;
+ var f;
+ var i;
+
+ min = 1; // 10^min
+ max = 6; // 10^max
+
+ for ( i = min; i <= max; i++ ) {
+ N = floor( pow( pow( 10, i ), 1.0/3.0 ) );
+ sh = [ N, N, N ];
+ f = createBenchmark( sh );
+ bench( pkg+'::equidimensional:size='+numel( sh ), f );
+ }
+}
+
+main();
diff --git a/base/unary3d-by/docs/repl.txt b/base/unary3d-by/docs/repl.txt
new file mode 100644
index 00000000..e79350c2
--- /dev/null
+++ b/base/unary3d-by/docs/repl.txt
@@ -0,0 +1,46 @@
+
+{{alias}}( arrays, shape, fcn, clbk[, thisArg] )
+ Applies a unary function to each element retrieved from a three-dimensional
+ nested input array according to a callback function and assigns results to
+ elements in a three-dimensional nested output array.
+
+ The callback function is provided the following arguments:
+
+ - value: array element.
+ - indices: current array element indices.
+ - arrays: input and output arrays.
+
+ If the callback function does not return any value (or equivalently,
+ explicitly returns `undefined`), the value is ignored.
+
+ Parameters
+ ----------
+ arrays: ArrayLikeObject
+ Array-like object containing one input nested array and one output
+ nested array.
+
+ shape: Array
+ Array shape.
+
+ fcn: Function
+ Unary function to apply to callback return values.
+
+ clbk: Function
+ Callback function.
+
+ thisArg: any (optional)
+ Callback execution context.
+
+ Examples
+ --------
+ > var x = [ [ [ -1.0, -2.0 ], [ -3.0, -4.0 ] ] ];
+ > var y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+ > var shape = [ 1, 2, 2 ];
+ > function clbk( v ) { return v * 2.0; };
+ > {{alias}}( [ x, y ], shape, {{alias:@stdlib/math/base/special/abs}}, clbk );
+ > y
+ [ [ [ 2.0, 4.0 ], [ 6.0, 8.0 ] ] ]
+
+ See Also
+ --------
+
diff --git a/base/unary3d-by/docs/types/index.d.ts b/base/unary3d-by/docs/types/index.d.ts
new file mode 100644
index 00000000..f98ee275
--- /dev/null
+++ b/base/unary3d-by/docs/types/index.d.ts
@@ -0,0 +1,117 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 { Array3D } from '@stdlib/types/array';
+import { Shape3D } from '@stdlib/types/ndarray';
+
+/**
+* Returns the accessed value.
+*
+* @returns accessed value
+*/
+type NullaryCallback = ( this: W ) => U;
+
+/**
+* Returns the accessed value.
+*
+* @param value - array element value
+* @returns accessed value
+*/
+type UnaryCallback = ( this: W, value: T ) => U;
+
+/**
+* Returns the accessed value.
+*
+* @param value - array element value
+* @param indices - current array element indices
+* @returns accessed value
+*/
+type BinaryCallback = ( this: W, value: T, indices: Array ) => U;
+
+/**
+* Returns the accessed value.
+*
+* @param value - array element value
+* @param indices - current array element indices
+* @returns accessed value
+*/
+type TernaryCallback = ( this: W, value: T, indices: Array, arrays: [ Array3D, Array3D ] ) => U;
+
+/**
+* Returns the accessed value.
+*
+* @param value - array element value
+* @param indices - current array element indices
+* @param arrays - input and output arrays
+* @returns accessed value
+*/
+type Callback = NullaryCallback | UnaryCallback | BinaryCallback | TernaryCallback;
+
+/**
+* Callback invoked for each nested array element retrieved via a callback function.
+*
+* @param value - array element
+* @returns result
+*/
+type Unary = ( value: U ) => V;
+
+/**
+* Applies a unary function to each element retrieved from a three-dimensional nested input array according to a callback function and assigns results to elements in a three-dimensional nested output array.
+*
+* ## Notes
+*
+* - The function assumes that the input and output arrays have the same shape.
+*
+* @param arrays - array containing one input nested array and one output nested array
+* @param shape - array shape
+* @param fcn - unary function to apply to callback return values
+* @param clbk - callback function
+* @param thisArg - callback execution context
+*
+* @example
+* var ones3d = require( '@stdlib/array/base/ones3d' );
+* var zeros3d = require( '@stdlib/array/base/zeros3d' );
+*
+* function accessor( v ) {
+* return v - 2.0;
+* }
+*
+* function scale( x ) {
+* return x * 10.0;
+* }
+*
+* var shape = [ 1, 2, 2 ];
+*
+* var x = ones3d( shape );
+* var y = zeros3d( shape );
+*
+* unary3dBy( [ x, y ], shape, scale );
+*
+* console.log( y );
+* // => [ [ [ -10.0, -10.0 ], [ -10.0, -10.0 ] ] ]
+*/
+declare function unary3dBy( arrays: [ Array3D, Array3D ], shape: Shape3D, fcn: Unary, clbk: Callback, thisArg?: ThisParameterType> ): void;
+
+
+// EXPORTS //
+
+export = unary3dBy;
diff --git a/base/unary3d-by/docs/types/test.ts b/base/unary3d-by/docs/types/test.ts
new file mode 100644
index 00000000..f9607b31
--- /dev/null
+++ b/base/unary3d-by/docs/types/test.ts
@@ -0,0 +1,142 @@
+/*
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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.
+*/
+
+import unary3dBy = require( './index' );
+
+/**
+* Unary function.
+*
+* @param value - input value
+* @returns result
+*/
+function identity( value: number ): number {
+ return value;
+}
+
+
+// TESTS //
+
+// The function returns undefined...
+{
+ const x = [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ];
+ const y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, identity ); // $ExpectType void
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, identity, {} ); // $ExpectType void
+}
+
+// The compiler throws an error if the function is provided a first argument which is not an array of nested arrays...
+{
+ unary3dBy( 'abc', [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( 3.14, [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( true, [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( false, [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( null, [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( [ '1' ], [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( {}, [ 1, 2, 2 ], identity, identity ); // $ExpectError
+ unary3dBy( ( x: number ): number => x, [ 1, 2, 2 ], identity, identity ); // $ExpectError
+
+ unary3dBy( 'abc', [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( 3.14, [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( true, [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( false, [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( null, [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( [ '1' ], [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( {}, [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+ unary3dBy( ( x: number ): number => x, [ 1, 2, 2 ], identity, identity, {} ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided a second argument which is not an array of numbers...
+{
+ const x = [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ];
+ const y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+ unary3dBy( [ x, y ], 'abc', identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], 3.14, identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], true, identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], false, identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], null, identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ '1' ], identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], {}, identity, identity ); // $ExpectError
+ unary3dBy( [ x, y ], ( x: number ): number => x, identity, identity ); // $ExpectError
+
+ unary3dBy( [ x, y ], 'abc', identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], 3.14, identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], true, identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], false, identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], null, identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ '1' ], identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], {}, identity, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], ( x: number ): number => x, identity, identity, {} ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided a third argument which is not a valid function...
+{
+ const x = [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ];
+ const y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], 'abc', identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], 3.14, identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], true, identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], false, identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], null, identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], [ '1' ], identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], {}, identity ); // $ExpectError
+
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], 'abc', identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], 3.14, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], true, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], false, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], null, identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], [ '1' ], identity, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], {}, identity, {} ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided a fourth argument which is not a valid function...
+{
+ const x = [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ];
+ const y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, 'abc' ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, 3.14 ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, true ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, false ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, null ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, [ '1' ] ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, {} ); // $ExpectError
+
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, 'abc', {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, 3.14, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, true, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, false, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, null, {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, [ '1' ], {} ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, {}, {} ); // $ExpectError
+}
+
+// The compiler throws an error if the function is provided an unsupported number of arguments...
+{
+ const x = [ [ [ 1.0, 2.0 ], [ 3.0, 4.0 ] ] ];
+ const y = [ [ [ 0.0, 0.0 ], [ 0.0, 0.0 ] ] ];
+
+ unary3dBy(); // $ExpectError
+ unary3dBy( [ x, y ] ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ] ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity ); // $ExpectError
+ unary3dBy( [ x, y ], [ 1, 2, 2 ], identity, identity, {}, {} ); // $ExpectError
+}
diff --git a/base/unary3d-by/examples/index.js b/base/unary3d-by/examples/index.js
new file mode 100644
index 00000000..37ac73ab
--- /dev/null
+++ b/base/unary3d-by/examples/index.js
@@ -0,0 +1,42 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 discreteUniform = require( '@stdlib/random/base/discrete-uniform' ).factory;
+var bernoulli = require( '@stdlib/random/base/bernoulli' );
+var filled3dBy = require( './../../../base/filled3d-by' );
+var zeros3d = require( './../../../base/zeros3d' );
+var abs = require( '@stdlib/math/base/special/abs' );
+var unary3dBy = require( './../lib' );
+
+function accessor( v ) {
+ // Randomly determine whether a value should be considered "missing":
+ return ( bernoulli( 0.5 ) > 0 ) ? v : void 0;
+}
+
+var shape = [ 3, 3, 3 ];
+
+var x = filled3dBy( shape, discreteUniform( -100, 100 ) );
+console.log( x );
+
+var y = zeros3d( shape );
+console.log( y );
+
+unary3dBy( [ x, y ], shape, abs, accessor );
+console.log( y );
diff --git a/base/unary3d-by/lib/index.js b/base/unary3d-by/lib/index.js
new file mode 100644
index 00000000..925350ae
--- /dev/null
+++ b/base/unary3d-by/lib/index.js
@@ -0,0 +1,57 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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';
+
+/**
+* Apply a unary function to each element retrieved from a three-dimensional nested input array according to a callback function and assign results to elements in a three-dimensional nested output array.
+*
+* @module @stdlib/array/base/unary3d-by
+*
+* @example
+* var ones3d = require( '@stdlib/array/base/ones3d' );
+* var zeros3d = require( '@stdlib/array/base/zeros3d' );
+* var unary3dBy = require( '@stdlib/array/base/unary3d-by' );
+*
+* function accessor( v ) {
+* return v - 2.0;
+* }
+*
+* function scale( x ) {
+* return x * 10.0;
+* }
+*
+* var shape = [ 1, 2, 2 ];
+*
+* var x = ones3d( shape );
+* var y = zeros3d( shape );
+*
+* unary3dBy( [ x, y ], shape, scale, accessor );
+*
+* console.log( y );
+* // => [ [ [ -10.0, -10.0 ], [ -10.0, -10.0 ] ] ]
+*/
+
+// MODULES //
+
+var main = require( './main.js' );
+
+
+// EXPORTS //
+
+module.exports = main;
diff --git a/base/unary3d-by/lib/main.js b/base/unary3d-by/lib/main.js
new file mode 100644
index 00000000..d88eeb40
--- /dev/null
+++ b/base/unary3d-by/lib/main.js
@@ -0,0 +1,105 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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';
+
+// MAIN //
+
+/**
+* Applies a unary function to each element retrieved from a three-dimensional nested input array according to a callback function and assigns results to elements in a three-dimensional nested output array.
+*
+* ## Notes
+*
+* - The function assumes that the input and output arrays have the same shape.
+*
+* @param {ArrayLikeObject} arrays - array-like object containing one input nested array and one output nested array
+* @param {NonNegativeIntegerArray} shape - array shape
+* @param {Function} fcn - unary function to apply to callback return values
+* @param {Callback} clbk - callback function
+* @param {*} [thisArg] - callback execution context
+* @returns {void}
+*
+* @example
+* var ones3d = require( '@stdlib/array/base/ones3d' );
+* var zeros3d = require( '@stdlib/array/base/zeros3d' );
+*
+* function accessor( v ) {
+* return v - 2.0;
+* }
+*
+* function scale( x ) {
+* return x * 10.0;
+* }
+*
+* var shape = [ 1, 2, 2 ];
+*
+* var x = ones3d( shape );
+* var y = zeros3d( shape );
+*
+* unary3dBy( [ x, y ], shape, scale, accessor );
+*
+* console.log( y );
+* // => [ [ [ -10.0, -10.0 ], [ -10.0, -10.0 ] ] ]
+*/
+function unary3dBy( arrays, shape, fcn, clbk ) {
+ var thisArg;
+ var S0;
+ var S1;
+ var S2;
+ var i0;
+ var i1;
+ var i2;
+ var x0;
+ var x1;
+ var y0;
+ var y1;
+ var x;
+ var y;
+ var v;
+
+ S0 = shape[ 2 ];
+ S1 = shape[ 1 ];
+ S2 = shape[ 0 ];
+ if ( S0 <= 0 || S1 <= 0 || S2 <= 0 ) {
+ return;
+ }
+ if ( arguments.length > 4 ) {
+ thisArg = arguments[ 4 ];
+ }
+ x = arrays[ 0 ];
+ y = arrays[ 1 ];
+ for ( i2 = 0; i2 < S2; i2++ ) {
+ x1 = x[ i2 ];
+ y1 = y[ i2 ];
+ for ( i1 = 0; i1 < S1; i1++ ) {
+ x0 = x1[ i1 ];
+ y0 = y1[ i1 ];
+ for ( i0 = 0; i0 < S0; i0++ ) {
+ v = clbk.call( thisArg, x0[ i0 ], [ i2, i1, i0 ], [ x, y ] );
+ if ( v !== void 0 ) {
+ y0[ i0 ] = fcn( v );
+ }
+ }
+ }
+ }
+}
+
+
+// EXPORTS //
+
+module.exports = unary3dBy;
diff --git a/base/unary3d-by/package.json b/base/unary3d-by/package.json
new file mode 100644
index 00000000..088e3504
--- /dev/null
+++ b/base/unary3d-by/package.json
@@ -0,0 +1,69 @@
+{
+ "name": "@stdlib/array/base/unary3d-by",
+ "version": "0.0.0",
+ "description": "Apply a unary function to each element retrieved from a three-dimensional nested input array according to a callback function and assign results to elements in a three-dimensional nested output array.",
+ "license": "Apache-2.0",
+ "author": {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ },
+ "contributors": [
+ {
+ "name": "The Stdlib Authors",
+ "url": "https://github.com/stdlib-js/stdlib/graphs/contributors"
+ }
+ ],
+ "main": "./lib",
+ "directories": {
+ "benchmark": "./benchmark",
+ "doc": "./docs",
+ "example": "./examples",
+ "lib": "./lib",
+ "test": "./test"
+ },
+ "types": "./docs/types",
+ "scripts": {},
+ "homepage": "https://github.com/stdlib-js/stdlib",
+ "repository": {
+ "type": "git",
+ "url": "git://github.com/stdlib-js/stdlib.git"
+ },
+ "bugs": {
+ "url": "https://github.com/stdlib-js/stdlib/issues"
+ },
+ "dependencies": {},
+ "devDependencies": {},
+ "engines": {
+ "node": ">=0.10.0",
+ "npm": ">2.7.0"
+ },
+ "os": [
+ "aix",
+ "darwin",
+ "freebsd",
+ "linux",
+ "macos",
+ "openbsd",
+ "sunos",
+ "win32",
+ "windows"
+ ],
+ "keywords": [
+ "stdlib",
+ "base",
+ "array",
+ "multidimensional",
+ "ndarray",
+ "matrix",
+ "3d",
+ "unary",
+ "apply",
+ "foreach",
+ "map",
+ "transform",
+ "accessor",
+ "callback",
+ "clbk"
+ ],
+ "__stdlib__": {}
+}
diff --git a/base/unary3d-by/test/test.js b/base/unary3d-by/test/test.js
new file mode 100644
index 00000000..633c7199
--- /dev/null
+++ b/base/unary3d-by/test/test.js
@@ -0,0 +1,279 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2024 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 tape = require( 'tape' );
+var abs = require( '@stdlib/math/base/special/abs' );
+var zeros3d = require( './../../../base/zeros3d' );
+var numel = require( '@stdlib/ndarray/base/numel' );
+var unary3dBy = require( './../lib' );
+
+
+// FUNCTIONS //
+
+function accessor( v ) {
+ if ( v === void 0 ) {
+ return;
+ }
+ return v * 2.0;
+}
+
+
+// TESTS //
+
+tape( 'main export is a function', function test( t ) {
+ t.ok( true, __filename );
+ t.strictEqual( typeof unary3dBy, 'function', 'main export is a function' );
+ t.end();
+});
+
+tape( 'the function applies a function to each nested input array element according to a callback function and assigns results to a nested output array', function test( t ) {
+ var expected;
+ var shape;
+ var x;
+ var y;
+
+ shape = [ 2, 2, 2 ];
+ x = [
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ],
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ]
+ ];
+
+ expected = [
+ [
+ [ 2.0, 4.0 ],
+ [ 6.0, 8.0 ]
+ ],
+ [
+ [ 2.0, 4.0 ],
+ [ 6.0, 8.0 ]
+ ]
+ ];
+
+ y = zeros3d( shape );
+ unary3dBy( [ x, y ], shape, abs, accessor );
+
+ t.deepEqual( y, expected, 'returns expected value' );
+
+ shape = [ 2, 2, 2 ];
+ x = [
+ [
+ [ -1.0, void 0 ],
+ [ void 0, -4.0 ]
+ ],
+ [
+ [ -1.0, void 0 ],
+ [ void 0, -4.0 ]
+ ]
+ ];
+
+ expected = [
+ [
+ [ 2.0, 0.0 ],
+ [ 0.0, 8.0 ]
+ ],
+ [
+ [ 2.0, 0.0 ],
+ [ 0.0, 8.0 ]
+ ]
+ ];
+
+ y = zeros3d( shape );
+ unary3dBy( [ x, y ], shape, abs, accessor );
+
+ t.deepEqual( y, expected, 'returns expected value' );
+ t.end();
+});
+
+tape( 'the function does not invoke provided functions if provided a shape having a first element equal to zero', function test( t ) {
+ var expected;
+ var shape;
+ var x;
+ var y;
+
+ shape = [ 1, 2, 2 ];
+ x = [
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ]
+ ];
+
+ expected = zeros3d( shape );
+
+ y = zeros3d( shape );
+ unary3dBy( [ x, y ], [ 0, 2, 2 ], clbk, clbk );
+
+ t.deepEqual( y, expected, 'returns expected value' );
+ t.end();
+
+ function clbk() {
+ t.ok( false, 'should not invoke function' );
+ }
+});
+
+tape( 'the function does not invoke provided functions if provided a shape having a second element equal to zero', function test( t ) {
+ var expected;
+ var shape;
+ var x;
+ var y;
+
+ shape = [ 1, 2, 2 ];
+ x = [
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ]
+ ];
+
+ expected = zeros3d( shape );
+
+ y = zeros3d( shape );
+ unary3dBy( [ x, y ], [ 1, 0, 2 ], clbk, clbk );
+
+ t.deepEqual( y, expected, 'returns expected value' );
+ t.end();
+
+ function clbk() {
+ t.ok( false, 'should not invoke function' );
+ }
+});
+
+tape( 'the function does not invoke provided functions if provided a shape having a third element equal to zero', function test( t ) {
+ var expected;
+ var shape;
+ var x;
+ var y;
+
+ shape = [ 1, 2, 2 ];
+ x = [
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ]
+ ];
+
+ expected = zeros3d( shape );
+
+ y = zeros3d( shape );
+ unary3dBy( [ x, y ], [ 1, 2, 0 ], clbk, clbk );
+
+ t.deepEqual( y, expected, 'returns expected value' );
+ t.end();
+
+ function clbk() {
+ t.ok( false, 'should not invoke function' );
+ }
+});
+
+tape( 'the function invokes the callback with three arguments', function test( t ) {
+ var expected;
+ var indices;
+ var values;
+ var arrays;
+ var shape;
+ var x;
+ var y;
+
+ shape = [ 1, 2, 2 ];
+ x = [
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ]
+ ];
+
+ y = zeros3d( shape );
+
+ values = [];
+ indices = [];
+ arrays = [];
+ unary3dBy( [ x, y ], shape, abs, clbk );
+
+ expected = [
+ -1.0,
+ -2.0,
+ -3.0,
+ -4.0
+ ];
+ t.deepEqual( values, expected, 'returns expected value' );
+
+ expected = [
+ [ 0, 0, 0 ],
+ [ 0, 0, 1 ],
+ [ 0, 1, 0 ],
+ [ 0, 1, 1 ]
+ ];
+ t.deepEqual( indices, expected, 'returns expected value' );
+
+ expected = [
+ [ x, y ],
+ [ x, y ],
+ [ x, y ],
+ [ x, y ]
+ ];
+ t.deepEqual( arrays, expected, 'returns expected value' );
+
+ t.end();
+
+ function clbk( v, idx, arr ) {
+ values.push( v );
+ indices.push( idx );
+ arrays.push( arr );
+ return v * 2.0;
+ }
+});
+
+tape( 'the function supports providing a callback execution context', function test( t ) {
+ var shape;
+ var ctx;
+ var x;
+ var y;
+
+ shape = [ 1, 2, 2 ];
+ x = [
+ [
+ [ -1.0, -2.0 ],
+ [ -3.0, -4.0 ]
+ ]
+ ];
+
+ y = zeros3d( shape );
+
+ ctx = {
+ 'count': 0
+ };
+ unary3dBy( [ x, y ], shape, abs, clbk, ctx );
+
+ t.strictEqual( ctx.count, numel( shape ), 'returns expected value' );
+ t.end();
+
+ function clbk( v ) {
+ this.count += 1; // eslint-disable-line no-invalid-this
+ return v * 2.0;
+ }
+});