From 058d7553cba7af2116020e995ba74f8bf76b3086 Mon Sep 17 00:00:00 2001
From: Jiacheng Huang <huangjiacheng0709@outlook.com>
Date: Sat, 9 May 2026 18:19:14 +0800
Subject: [PATCH] feat: add `softplus_backward` base

---
 src/base/softplus_backward.h | 57 ++++++++++++++++++++++++++++++++++++
 1 file changed, 57 insertions(+)
 create mode 100644 src/base/softplus_backward.h

diff --git a/src/base/softplus_backward.h b/src/base/softplus_backward.h
new file mode 100644
index 00000000..ce3ebf4c
--- /dev/null
+++ b/src/base/softplus_backward.h
@@ -0,0 +1,57 @@
+#ifndef INFINI_OPS_BASE_SOFTPLUS_BACKWARD_H_
+#define INFINI_OPS_BASE_SOFTPLUS_BACKWARD_H_
+
+#include "operator.h"
+
+namespace infini::ops {
+
+class SoftplusBackward : public Operator<SoftplusBackward> {
+ public:
+  SoftplusBackward(const Tensor grad_output, const Tensor input,
+                   const double beta, const double threshold, Tensor grad_input)
+      : grad_output_shape_{grad_output.shape()},
+        grad_output_strides_{grad_output.strides()},
+        grad_output_type_{grad_output.dtype()},
+        input_shape_{input.shape()},
+        input_strides_{input.strides()},
+        input_type_{input.dtype()},
+        grad_input_shape_{grad_input.shape()},
+        grad_input_strides_{grad_input.strides()},
+        grad_input_type_{grad_input.dtype()},
+        beta_{beta},
+        threshold_{threshold},
+        device_index_{grad_input.device().index()} {}
+
+  virtual void operator()(const Tensor grad_output, const Tensor input,
+                          const double beta, const double threshold,
+                          Tensor grad_input) const = 0;
+
+ protected:
+  Tensor::Shape grad_output_shape_;
+
+  Tensor::Strides grad_output_strides_;
+
+  DataType grad_output_type_;
+
+  Tensor::Shape input_shape_;
+
+  Tensor::Strides input_strides_;
+
+  DataType input_type_;
+
+  Tensor::Shape grad_input_shape_;
+
+  Tensor::Strides grad_input_strides_;
+
+  DataType grad_input_type_;
+
+  double beta_{};
+
+  double threshold_{};
+
+  int device_index_{0};
+};
+
+}  // namespace infini::ops
+
+#endif