chore: import upstream snapshot with attribution

2026-07-13 12:47:05 +08:00
commit 4f3b7da785
7394 changed files with 2005594 additions and 0 deletions
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+/* ******************************************************************************
+ *
+ *
+ * This program and the accompanying materials are made available under the
+ * terms of the Apache License, Version 2.0 which is available at
+ * https://www.apache.org/licenses/LICENSE-2.0.
+ *
+ *  See the NOTICE file distributed with this work for additional
+ *  information regarding copyright ownership.
+ * 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.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ ******************************************************************************/
+
+//
+// Created by Yurii Shyrma on 12.12.2017
+//
+#include <array/NDArrayFactory.h>
+#include <execution/Threads.h>
+#include <ops/declarable/helpers/gammaMathFunc.h>
+#include <ops/declarable/helpers/zeta.h>
+#if NOT_EXCLUDED(OP_polygamma)
+namespace sd {
+namespace ops {
+namespace helpers {
+
+//////////////////////////////////////////////////////////////////////////
+// calculate factorial
+template <typename T>
+static SD_INLINE T getFactorial(const int n) {
+  if (n < 0) THROW_EXCEPTION("factorial is not defined for negative number !");
+
+  if (n == 0 || n == 1) return (T)1.f;
+
+  T result = (T)1.f;
+
+  for (int i = 2; i <= n; ++i) result *= i;
+
+  return result;
+}
+
+//////////////////////////////////////////////////////////////////////////
+// implementation is based on serial representation written in terms of the Hurwitz zeta function as polygamma =
+// (-1)^{n+1} * n! * zeta(n+1, x)
+template <typename T>
+static SD_INLINE T polyGammaScalar(sd::LaunchContext* context, const int n, const T x) {
+  int sign = (n + 1) % 2 ? -1 : 1;
+  T zeta = zetaScalar<T>(T(n + 1), x);
+  return T(sign) * getFactorial<T>(n) * zeta;
+}
+
+//////////////////////////////////////////////////////////////////////////
+// calculate polygamma function for arrays
+template <typename T>
+static void polyGamma_(sd::LaunchContext* context, NDArray& n, NDArray& x, NDArray& output) {
+  auto func = PRAGMA_THREADS_FOR {
+    for (auto i = start; i < stop; i++) {
+      const T order = n.e<T>(i);
+      if (order !=
+          static_cast<int>(order))  // if order has fractional part then do not perform calculations and return NAN
+        output.p(i, std::numeric_limits<T>::quiet_NaN());
+      else if (order == 0)  // polygamma function of zero order is digamma function
+        output.p(i, diGammaScalar<T>(x.e<T>(i)));
+      else
+        output.p(i, polyGammaScalar<T>(context, order, x.e<T>(i)));
+    }
+  };
+  samediff::Threads::parallel_for(func, 0, x.lengthOf());
+}
+
+void polyGamma(sd::LaunchContext* context, NDArray& n, NDArray& x, NDArray& output) {
+  BUILD_SINGLE_SELECTOR(x.dataType(), polyGamma_, (context, n, x, output), SD_FLOAT_TYPES);
+}
+
+BUILD_SINGLE_TEMPLATE( void polyGamma_,
+                      (sd::LaunchContext * context, NDArray& n, NDArray& x, NDArray& output),
+                      SD_FLOAT_TYPES);
+
+}  // namespace helpers
+}  // namespace ops
+}  // namespace sd
+#endif