load LRN bias from param

src/layer/arm/lrn_arm.cpp

@@ -130,7 +130,7 @@ int LRN_arm::forward_inplace(Mat& bottom_top_blob) const
 #endif // __ARM_NEON
 
 #if __ARM_NEON
-            float32x4_t _v1 = vdupq_n_f32(1.f);
+            float32x4_t _bias = vdupq_n_f32(bias);
             float32x4_t _ads = vdupq_n_f32(alpha_div_size);
             float32x4_t _mb = vdupq_n_f32(-beta);
             for (; nn>0; nn--)
@@ -138,7 +138,7 @@ int LRN_arm::forward_inplace(Mat& bottom_top_blob) const
                 float32x4_t _p = vld1q_f32(ptr);
                 float32x4_t _ssp = vld1q_f32(ssptr);
                 _ssp = vmulq_f32(_ssp, _ads);
-                _ssp = vaddq_f32(_ssp, _v1);
+                _ssp = vaddq_f32(_ssp, _bias);
                 _ssp = pow_ps(_ssp, _mb);
                 _p = vmulq_f32(_p, _ssp);
                 vst1q_f32(ptr, _p);
@@ -149,7 +149,7 @@ int LRN_arm::forward_inplace(Mat& bottom_top_blob) const
 #endif // __ARM_NEON
             for (; remain>0; remain--)
             {
-                *ptr = *ptr * pow(1.f + alpha_div_size * *ssptr, -beta);
+                *ptr = *ptr * pow(bias + alpha_div_size * *ssptr, -beta);
 
                 ssptr++;
                 ptr++;
@@ -216,7 +216,7 @@ int LRN_arm::forward_inplace(Mat& bottom_top_blob) const
                         ss += val;
                     }
 
-                    ptr[j] = ptr[j] * pow(1.f + alpha_div_size * ss, -beta);
+                    ptr[j] = ptr[j] * pow(bias + alpha_div_size * ss, -beta);
                 }
 
                 ptr += outw;

src/layer/lrn.cpp

@@ -31,6 +31,7 @@ int LRN::load_param(const ParamDict& pd)
     local_size = pd.get(1, 5);
     alpha = pd.get(2, 1.f);
     beta = pd.get(3, 0.75f);
+    bias = pd.get(4, 1.f);
 
     return 0;
 }
@@ -90,7 +91,7 @@ int LRN::forward_inplace(Mat& bottom_top_blob) const
             float* ptr = bottom_top_blob.channel(q);
             for (int i=0; i<size; i++)
             {
-                ptr[i] = ptr[i] * pow(1.f + alpha_div_size * ssptr[i], -beta);
+                ptr[i] = ptr[i] * pow(bias + alpha_div_size * ssptr[i], -beta);
             }
         }
     }
@@ -154,7 +155,7 @@ int LRN::forward_inplace(Mat& bottom_top_blob) const
                         ss += val;
                     }
 
-                    ptr[j] = ptr[j] * pow(1.f + alpha_div_size * ss, -beta);
+                    ptr[j] = ptr[j] * pow(bias + alpha_div_size * ss, -beta);
                 }
 
                 ptr += outw;

src/layer/lrn.h

@@ -36,6 +36,7 @@ public:
     int local_size;
     float alpha;
     float beta;
+    float bias;
 };
 
 } // namespace ncnn