feat: add the C src files

Author: anandkaranubc

lib/node_modules/@stdlib/stats/base/dists/chi/entropy/include/stdlib/stats/base/dists/chi/entropy.h

@@ -0,0 +1,41 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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.
+*/
+
+#ifndef STDLIB_STATS_BASE_DISTS_CHI_ENTROPY_H
+#define STDLIB_STATS_BASE_DISTS_CHI_ENTROPY_H
+
+/*
+* If C++, prevent name mangling so that the compiler emits a binary file having undecorated names, thus mirroring the behavior of a C compiler.
+*/
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+* Returns the differential entropy of a chi distribution.
+*
+* @param k    degrees of freedom (must be positive)
+* @return     entropy
+*/
+double stdlib_base_dists_chi_entropy( const double k );
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif // !STDLIB_STATS_BASE_DISTS_CHI_ENTROPY_H

lib/node_modules/@stdlib/stats/base/dists/chi/entropy/src/Makefile

@@ -0,0 +1,70 @@
+#/
+# @license Apache-2.0
+#
+# Copyright (c) 2025 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
+
+
+# RULES #
+
+#/
+# Removes generated files for building an add-on.
+#
+# @example
+# make clean-addon
+#/
+clean-addon:
+	$(QUIET) -rm -f *.o *.node
+
+.PHONY: clean-addon
+
+#/
+# Removes generated files.
+#
+# @example
+# make clean
+#/
+clean: clean-addon
+
+.PHONY: clean

lib/node_modules/@stdlib/stats/base/dists/chi/entropy/src/addon.c

@@ -0,0 +1,23 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2025 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.
+*/
+
+#include "stdlib/math/base/napi/unary.h"
+#include "stdlib/stats/base/dists/chi/entropy.h"
+
+// cppcheck-suppress shadowFunction
+STDLIB_MATH_BASE_NAPI_MODULE_D_D( stdlib_base_dists_chi_entropy )

lib/node_modules/@stdlib/stats/base/dists/chi/entropy/src/main.c

@@ -0,0 +1,54 @@
+/**
+* @license Apache-2.0
+*
+* Copyright (c) 2018 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.
+*/
+
+#include "stdlib/math/base/assert/is_nan.h"
+#include "stdlib/math/base/special/digamma.h"
+#include "stdlib/math/base/special/gammaln.h"
+#include "stdlib/constants/float64/ln_two.h"
+
+/**
+* Returns the differential entropy of a chi distribution.
+*
+* @param k    degrees of freedom (must be positive)
+* @return     entropy, or NaN if input is invalid
+*
+* @example
+* double v = stdlib_base_dists_chi_entropy( 9.0 );
+* // returns ~1.052
+*
+* @example
+* double v = stdlib_base_dists_chi_entropy( 1.0 );
+* // returns ~0.726
+*
+* @example
+* double v = stdlib_base_dists_chi_entropy( -0.2 );
+* // returns NaN
+*
+* @example
+* double v = stdlib_base_dists_chi_entropy( NAN );
+* // returns NaN
+*/
+double stdlib_base_dists_chi_entropy( const double k ) {
+    if ( stdlib_base_is_nan( k ) || k <= 0.0 ) {
+        return 0.0 / 0.0; // NaN
+    }
+    double kh = k / 2.0;
+    return stdlib_base_gammaln( kh ) +
+           ( 0.5 * ( k - STDLIB_CONSTANT_FLOAT64_LN2 -
+             ( ( k - 1.0 ) * stdlib_base_digamma( kh ) ) ) );
+}