feat: add C implementation for blas/ext/base/ndarray/dcartesian-product

lib/node_modules/@stdlib/blas/ext/base/ndarray/dcartesian-product/README.md

@@ -113,6 +113,126 @@ console.log( ndarray2array( v ) );
 
 <!-- /.examples -->
 
+<!-- C interface documentation. -->
+
+* * *
+
+<section class="c">
+
+## C APIs
+
+<section class="usage">
+
+### Usage
+
+```c
+#include "stdlib/blas/ext/base/ndarray/dcartesian_product.h"
+```
+
+#### stdlib_blas_ext_dcartesian_product( arrays )
+
+Computes the Cartesian product for two double-precision floating-point ndarrays and stores each pair in a row of a two-dimensional output ndarray.
+
+The function accepts the following arguments:
+
+-   **arrays**: `[in] struct ndarray**` list containing two one-dimensional input ndarrays and a two-dimensional output ndarray.
+
+```c
+void stdlib_blas_ext_dcartesian_product( const struct ndarray *arrays[] );
+```
+
+</section>
+
+<!-- /.usage -->
+
+<section class="notes">
+
+### Notes
+
+-   For inputs of lengths `M` and `N`, the output ndarray should have shape `[M*N, 2]`.
+-   The first column contains elements from the first input and the second column contains elements from the second input.
+-   If `M <= 0` or `N <= 0`, the output ndarray is unchanged.
+-   C ndarray strides and offsets are specified in bytes. The function supports independently strided input and output views.
+
+</section>
+
+<!-- /.notes -->
+
+<section class="examples">
+
+### Examples
+
+```c
+#include "stdlib/blas/ext/base/ndarray/dcartesian_product.h"
+#include "stdlib/ndarray/ctor.h"
+#include "stdlib/ndarray/dtypes.h"
+#include "stdlib/ndarray/index_modes.h"
+#include "stdlib/ndarray/orders.h"
+#include "stdlib/ndarray/base/bytes_per_element.h"
+#include <stdint.h>
+#include <stdlib.h>
+#include <stdio.h>
+
+int main( void ) {
+    // Create data buffers:
+    const double dataX[] = { 1.0, 2.0 };
+    const double dataY[] = { 3.0, 4.0, 5.0 };
+    double dataOut[ 12 ];
+
+    // Specify input and output shapes:
+    int64_t shapeX[] = { 2 };
+    int64_t shapeY[] = { 3 };
+    int64_t shapeOut[] = { 6, 2 };
+
+    // Specify byte strides:
+    int64_t strides[] = { STDLIB_NDARRAY_FLOAT64_BYTES_PER_ELEMENT };
+    int64_t stridesOut[] = {
+        2 * STDLIB_NDARRAY_FLOAT64_BYTES_PER_ELEMENT,
+        STDLIB_NDARRAY_FLOAT64_BYTES_PER_ELEMENT
+    };
+
+    const enum STDLIB_NDARRAY_ORDER order = STDLIB_NDARRAY_ROW_MAJOR;
+    const enum STDLIB_NDARRAY_INDEX_MODE imode = STDLIB_NDARRAY_INDEX_ERROR;
+    int8_t submodes[] = { STDLIB_NDARRAY_INDEX_ERROR };
+
+    // Create input and output ndarrays:
+    // cppcheck-suppress invalidPointerCast
+    struct ndarray *x = stdlib_ndarray_allocate( STDLIB_NDARRAY_FLOAT64, (uint8_t *)dataX, 1, shapeX, strides, 0, order, imode, 1, submodes );
+
+    // cppcheck-suppress invalidPointerCast
+    struct ndarray *y = stdlib_ndarray_allocate( STDLIB_NDARRAY_FLOAT64, (uint8_t *)dataY, 1, shapeY, strides, 0, order, imode, 1, submodes );
+
+    // cppcheck-suppress invalidPointerCast
+    struct ndarray *out = stdlib_ndarray_allocate( STDLIB_NDARRAY_FLOAT64, (uint8_t *)dataOut, 2, shapeOut, stridesOut, 0, order, imode, 1, submodes );
+    if ( x == NULL || y == NULL || out == NULL ) {
+        stdlib_ndarray_free( x );
+        stdlib_ndarray_free( y );
+        stdlib_ndarray_free( out );
+        fprintf( stderr, "Error allocating memory.\n" );
+        exit( 1 );
+    }
+
+    const struct ndarray *arrays[] = { x, y, out };
+    stdlib_blas_ext_dcartesian_product( arrays );
+
+    // Print the resulting pairs:
+    for ( int i = 0; i < 6; i++ ) {
+        printf( "out[ %i ] = ( %lf, %lf )\n", i, dataOut[ i*2 ], dataOut[ (i*2)+1 ] );
+    }
+    stdlib_ndarray_free( x );
+    stdlib_ndarray_free( y );
+    stdlib_ndarray_free( out );
+}
+```
+
+</section>
+
+<!-- /.examples -->
+
+</section>
+
+<!-- /.c -->
+
 <!-- Section for related `stdlib` packages. Do not manually edit this section, as it is automatically populated. -->
 
 <section class="related">

lib/node_modules/@stdlib/blas/ext/base/ndarray/dcartesian-product/benchmark/benchmark.native.js

@@ -0,0 +1,116 @@
+/**
+* @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 resolve = require( 'path' ).resolve;
+var bench = require( '@stdlib/bench' );
+var uniform = require( '@stdlib/random/uniform' );
+var zeros = require( '@stdlib/ndarray/zeros' );
+var isnan = require( '@stdlib/math/base/assert/is-nan' );
+var pow = require( '@stdlib/math/base/special/pow' );
+var format = require( '@stdlib/string/format' );
+var tryRequire = require( '@stdlib/utils/try-require' );
+var pkg = require( './../package.json' ).name;
+
+
+// VARIABLES //
+
+var dcartesianProduct = tryRequire( resolve( __dirname, './../lib/native.js' ) );
+var opts = {
+	'skip': ( dcartesianProduct instanceof Error )
+};
+var options = {
+	'dtype': 'float64'
+};
+
+
+// FUNCTIONS //
+
+/**
+* Creates a benchmark function.
+*
+* @private
+* @param {PositiveInteger} len - array length
+* @returns {Function} benchmark function
+*/
+function createBenchmark( len ) {
+	var out;
+	var x;
+	var y;
+
+	x = uniform( [ len ], -100.0, 100.0, options );
+	y = uniform( [ len ], -100.0, 100.0, options );
+	out = zeros( [ len*len, 2 ], options );
+
+	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 = dcartesianProduct( [ x, y, out ] );
+			if ( typeof v !== 'object' ) {
+				b.fail( 'should return an ndarray' );
+			}
+		}
+		b.toc();
+		if ( isnan( v.get( i%(len*len), i%2 ) ) ) {
+			b.fail( 'should not return NaN' );
+		}
+		b.pass( 'benchmark finished' );
+		b.end();
+	}
+}
+
+
+// MAIN //
+
+/**
+* Main execution sequence.
+*
+* @private
+*/
+function main() {
+	var len;
+	var min;
+	var max;
+	var f;
+	var i;
+
+	min = 1; // 10^min
+	max = 3; // 10^max
+
+	for ( i = min; i <= max; i++ ) {
+		len = pow( 10, i );
+		f = createBenchmark( len );
+		bench( format( '%s::native:len=%d', pkg, len ), opts, f );
+	}
+}
+
+main();

lib/node_modules/@stdlib/blas/ext/base/ndarray/dcartesian-product/benchmark/c/Makefile

@@ -0,0 +1,146 @@
+#/
+# @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.
+#/
+
+# VARIABLES #
+
+ifndef VERBOSE
+	QUIET := @
+else
+	QUIET :=
+endif
+
+# Determine the OS ([1][1], [2][2]).
+#
+# [1]: https://en.wikipedia.org/wiki/Uname#Examples
+# [2]: http://stackoverflow.com/a/27776822/2225624
+OS ?= $(shell uname)
+ifneq (, $(findstring MINGW,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring MSYS,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring CYGWIN,$(OS)))
+	OS := WINNT
+else
+ifneq (, $(findstring Windows_NT,$(OS)))
+	OS := WINNT
+endif
+endif
+endif
+endif
+
+# Define the program used for compiling C source files:
+ifdef C_COMPILER
+	CC := $(C_COMPILER)
+else
+	CC := gcc
+endif
+
+# Define the command-line options when compiling C files:
+CFLAGS ?= \
+	-std=c99 \
+	-O3 \
+	-Wall \
+	-pedantic
+
+# Determine whether to generate position independent code ([1][1], [2][2]).
+#
+# [1]: https://gcc.gnu.org/onlinedocs/gcc/Code-Gen-Options.html#Code-Gen-Options
+# [2]: http://stackoverflow.com/questions/5311515/gcc-fpic-option
+ifeq ($(OS), WINNT)
+	fPIC ?=
+else
+	fPIC ?= -fPIC
+endif
+
+# List of includes (e.g., `-I /foo/bar -I /beep/boop/include`):
+INCLUDE ?=
+
+# List of source files:
+SOURCE_FILES ?=
+
+# List of libraries (e.g., `-lopenblas -lpthread`):
+LIBRARIES ?=
+
+# List of library paths (e.g., `-L /foo/bar -L /beep/boop`):
+LIBPATH ?=
+
+# List of C targets:
+c_targets := benchmark.length.out
+
+
+# RULES #
+
+#/
+# Compiles source files.
+#
+# @param {string} [C_COMPILER] - C compiler (e.g., `gcc`)
+# @param {string} [CFLAGS] - C compiler options
+# @param {(string|void)} [fPIC] - compiler flag determining whether to generate position independent code (e.g., `-fPIC`)
+# @param {string} [INCLUDE] - list of includes (e.g., `-I /foo/bar -I /beep/boop/include`)
+# @param {string} [SOURCE_FILES] - list of source files
+# @param {string} [LIBPATH] - list of library paths (e.g., `-L /foo/bar -L /beep/boop`)
+# @param {string} [LIBRARIES] - list of libraries (e.g., `-lopenblas -lpthread`)
+#
+# @example
+# make
+#
+# @example
+# make all
+#/
+all: $(c_targets)
+
+.PHONY: all
+
+#/
+# Compiles C source files.
+#
+# @private
+# @param {string} CC - C compiler (e.g., `gcc`)
+# @param {string} CFLAGS - C compiler options
+# @param {(string|void)} fPIC - compiler flag determining whether to generate position independent code (e.g., `-fPIC`)
+# @param {string} INCLUDE - list of includes (e.g., `-I /foo/bar`)
+# @param {string} SOURCE_FILES - list of source files
+# @param {string} LIBPATH - list of library paths (e.g., `-L /foo/bar`)
+# @param {string} LIBRARIES - list of libraries (e.g., `-lopenblas`)
+#/
+$(c_targets): %.out: %.c
+	$(QUIET) $(CC) $(CFLAGS) $(fPIC) $(INCLUDE) -o $@ $(SOURCE_FILES) $< $(LIBPATH) -lm $(LIBRARIES)
+
+#/
+# Runs compiled benchmarks.
+#
+# @example
+# make run
+#/
+run: $(c_targets)
+	$(QUIET) ./$<
+
+.PHONY: run
+
+#/
+# Removes generated files.
+#
+# @example
+# make clean
+#/
+clean:
+	$(QUIET) -rm -f *.o *.out
+
+.PHONY: clean