From 7e0d21de6d3352c1238d35d2586f40e48b6da27f Mon Sep 17 00:00:00 2001
From: chengduoZH <zhaochengduo@163.com>
Date: Tue, 30 Jan 2018 11:11:04 +0800
Subject: [PATCH] fix scale and bias dim

---
 paddle/operators/layer_norm_op.cc | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/paddle/operators/layer_norm_op.cc b/paddle/operators/layer_norm_op.cc
index 07ca8ac222..125ac9f53f 100644
--- a/paddle/operators/layer_norm_op.cc
+++ b/paddle/operators/layer_norm_op.cc
@@ -123,8 +123,8 @@ class LayerNormKernel<platform::CPUDeviceContext, T>
     int right = static_cast<int>(matrix_dim[1]);
 
     auto input_map = ConstEigenMatrixMapRowMajor<T>(x->data<T>(), left, right);
-    auto scale_map = ConstEigenMatrixMapRowMajor<T>(scale->data<T>(), left, 1);
-    auto bias_map = ConstEigenMatrixMapRowMajor<T>(bias->data<T>(), left, 1);
+    auto scale_map = ConstEigenMatrixMapRowMajor<T>(scale->data<T>(), 1, right);
+    auto bias_map = ConstEigenMatrixMapRowMajor<T>(bias->data<T>(), 1, right);
     auto mean_map = EigenMatrixMapRowMajor<T>(mean->data<T>(), left, 1);
     auto var_map = EigenMatrixMapRowMajor<T>(var->data<T>(), left, 1);
     auto output_map = EigenMatrixMapRowMajor<T>(output->data<T>(), left, right);
@@ -143,11 +143,11 @@ class LayerNormKernel<platform::CPUDeviceContext, T>
 
     // TODO(zcd): Some thinking about output_map, is it appropriate that
     // `output_map` and `input_map` point to the same memory.
-    auto inv_std_scale =
-        var_map.unaryExpr(inv_std_func).cwiseProduct(scale_map);
-    output_map =
-        inv_std_scale.replicate(1, right).cwiseProduct(input_map) +
-        (bias_map - inv_std_scale.cwiseProduct(mean_map)).replicate(1, right);
+    auto inv_std_scale = var_map.unaryExpr(inv_std_func);
+    output_map = (input_map - mean_map.replicate(1, right))
+                     .cwiseProduct(inv_std_scale.replicate(1, right))
+                     .cwiseProduct(scale_map.replicate(left, 1)) -
+                 bias_map.replicate(left, 1);
   }
 };
 
@@ -221,7 +221,7 @@ class LayerNormGradKernel<platform::CPUDeviceContext, T>
     auto *d_scale = ctx.Output<Tensor>(framework::GradVarName("Scale"));
     auto *d_bias = ctx.Output<Tensor>(framework::GradVarName("Bias"));
 
-    auto scale_map = ConstEigenMatrixMapRowMajor<T>(scale->data<T>(), left, 1);
+    auto scale_map = ConstEigenMatrixMapRowMajor<T>(scale->data<T>(), 1, right);
     auto x_map = ConstEigenMatrixMapRowMajor<T>(x->data<T>(), left, right);
     auto d_y_map = ConstEigenMatrixMapRowMajor<T>(d_y->data<T>(), left, right);
     auto mean_map = ConstEigenMatrixMapRowMajor<T>(mean->data<T>(), left, 1);
@@ -229,12 +229,13 @@ class LayerNormGradKernel<platform::CPUDeviceContext, T>
 
     if (d_bias) {
       d_bias->mutable_data<T>(ctx.GetPlace());
-      auto d_bias_map = EigenMatrixMapRowMajor<T>(d_bias->data<T>(), left, 1);
+      auto d_bias_map = EigenMatrixMapRowMajor<T>(d_bias->data<T>(), 1, right);
       d_bias_map = d_y_map.colwise().mean();
     }
     if (d_scale) {
       d_scale->mutable_data<T>(ctx.GetPlace());
-      auto d_scale_map = EigenMatrixMapRowMajor<T>(d_scale->data<T>(), left, 1);
+      auto d_scale_map =
+          EigenMatrixMapRowMajor<T>(d_scale->data<T>(), 1, right);
       auto inv_std_func = [](T ele) { return std::sqrt(1 / ele); };
       // There are two equation to compute d_scale. One uses "Y" and the other
       // does not use "Y"
@@ -254,15 +255,15 @@ class LayerNormGradKernel<platform::CPUDeviceContext, T>
       auto inv_std_func = [](T ele) { return std::sqrt(1 / ele); };
       // dy_dx
       auto dx_end = var_map.unaryExpr(inv_std_func)
-                        .cwiseProduct(scale_map)
                         .replicate(1, right)
-                        .cwiseProduct(d_y_map);
+                        .cwiseProduct(d_y_map)
+                        .cwiseProduct(scale_map.replicate(left, 1));
       // dy_dmean_dx
       auto dx_mean = (T(-1.0) / right) *
                      var_map.unaryExpr(inv_std_func)
-                         .cwiseProduct(scale_map)
                          .replicate(1, right)
                          .cwiseProduct(d_y_map)
+                         .cwiseProduct(scale_map.replicate(left, 1))
                          .rowwise()
                          .sum()
                          .replicate(1, right);
@@ -274,8 +275,8 @@ class LayerNormGradKernel<platform::CPUDeviceContext, T>
       auto dvar_end = var_map.unaryExpr(inv_std_func)
                           .unaryExpr(triple_product_func)
                           .cwiseProduct(dvar_end_part)
-                          .cwiseProduct(scale_map)
-                          .replicate(1, right);
+                          .replicate(1, right)
+                          .cwiseProduct(scale_map.replicate(left, 1));
       auto dx_var =
           (T(-1.0) / right) *
           (x_map - mean_map.replicate(1, right)).cwiseProduct(dvar_end);
-- 
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