fix type error of std::pow in sigmoid_focal_loss_op.cu and sigmoid_focal_loss_op.h (#18152)

* test=develop
fix type error of std::pow in sigmoid_focal_loss_op.cu and sigmoid_focal_loss_op.h

* test=develop
fix wrong code stype in sigmoid_focal_loss_op.cu and sigmoid_focal_loss_op.h

paddle/fluid/operators/detection/sigmoid_focal_loss_op.cu

@@ -61,8 +61,8 @@ __global__ void GPUSigmoidFocalLossForward(const T *x_data,
     T p = 1. / (1. + real_exp(-x));
 
     // (1 - p)**gamma * log(p)
-    T term_pos =
-        std::pow((1. - p), gamma) * real_log(p > FLT_MIN ? p : FLT_MIN);
+    T term_pos = std::pow(static_cast<T>(1. - p), gamma) *
+                 real_log(p > FLT_MIN ? p : FLT_MIN);
     // p**gamma * log(1 - p)
     T term_neg =
         std::pow(p, gamma) *
@@ -97,7 +97,7 @@ __global__ void GPUSigmoidFocalLossBackward(
     T p = 1. / (1. + real_exp(-x));
 
     // (1-p)**g * (1 - p - g*p*log(p))
-    T term_pos = std::pow((1. - p), gamma) *
+    T term_pos = std::pow(static_cast<T>(1. - p), gamma) *
                  (1. - p - (p * gamma * real_log(p > FLT_MIN ? p : FLT_MIN)));
     // (p**g) * (g*(1-p)*log(1-p) - p)
     T term_neg =

paddle/fluid/operators/detection/sigmoid_focal_loss_op.h

@@ -59,12 +59,13 @@ class SigmoidFocalLossKernel : public framework::OpKernel<T> {
       T p = 1. / (1. + std::exp(-x));
 
       // (1 - p)**gamma * log(p) where
-      T term_pos =
-          std::pow((1. - p), gamma) * std::log(p > FLT_MIN ? p : FLT_MIN);
+      T term_pos = std::pow(static_cast<T>(1. - p), gamma) *
+                   std::log(p > FLT_MIN ? p : FLT_MIN);
       // p**gamma * log(1 - p)
-      float term_neg =
+      T term_neg =
           std::pow(p, gamma) *
           (-1. * x * (x >= 0) - std::log(1. + std::exp(x - 2. * x * (x >= 0))));
+
       out_data[idx] = 0.0;
       out_data[idx] += -c_pos * term_pos * s_pos;
       out_data[idx] += -c_neg * term_neg * s_neg;
@@ -107,7 +108,7 @@ class SigmoidFocalLossGradKernel : public framework::OpKernel<T> {
       T p = 1. / (1. + std::exp(-x));
 
       // (1-p)**g * (1 - p - g*p*log(p))
-      T term_pos = std::pow((1. - p), gamma) *
+      T term_pos = std::pow(static_cast<T>(1. - p), gamma) *
                    (1. - p - (p * gamma * std::log(p > FLT_MIN ? p : FLT_MIN)));
       // (p**g) * (g*(1-p)*log(1-p) - p)
       T term_neg = std::pow(p, gamma) *
@@ -115,7 +116,6 @@ class SigmoidFocalLossGradKernel : public framework::OpKernel<T> {
                      std::log(1. + std::exp(x - 2. * x * (x >= 0)))) *
                         (1. - p) * gamma -
                     p);
-
       dx_data[idx] = 0.0;
       dx_data[idx] += -c_pos * s_pos * term_pos;
       dx_data[idx] += -c_neg * s_neg * term_neg;