From a92afc5a2d2667937507e94fdf0f2646cb2388bb Mon Sep 17 00:00:00 2001
From: sxjscience <xshiab@ust.hk>
Date: Wed, 6 Jan 2016 11:14:59 +0800
Subject: [PATCH 1/2] Add new operator `MatFillRowElement`, which sets the
 value of a specific element in each line of the data matrix.

---
 mshadow/extension.h      |   1 +
 mshadow/extension/fill.h | 102 +++++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 mshadow/extension/fill.h

diff --git a/mshadow/extension.h b/mshadow/extension.h
index 01e11f1ba9c0..66df5546fcc9 100644
--- a/mshadow/extension.h
+++ b/mshadow/extension.h
@@ -24,6 +24,7 @@
 #include "./extension/concat.h"
 #include "./extension/implicit_gemm.h"
 #include "./extension/choose.h"
+#include "./extension/fill.h"
 #include "./extension/one_hot.h"
 #include "./extension/slice.h"
 #include "./extension/take.h"
diff --git a/mshadow/extension/fill.h b/mshadow/extension/fill.h
new file mode 100644
index 000000000000..a7b60d258210
--- /dev/null
+++ b/mshadow/extension/fill.h
@@ -0,0 +1,102 @@
+/*!
+ *  Copyright (c) 2015 by Contributors
+ * \file fill.h
+ * \brief support for implicit array filling operation
+ * \author Xingjian Shi
+ */
+#ifndef MSHADOW_EXTENSION_FILL_H_
+#define MSHADOW_EXTENSION_FILL_H_
+
+#include "../extension.h"
+
+
+namespace mshadow {
+namespace expr {
+/*!
+ * \brief Set value of a specific element in each line of the data matrix.
+ * \tparam SrcExp type of src expression
+ * \tparam ValExp type of val expression
+ * \tparam IndexExp type of index expression
+ * \tparam DType the type of ret expression
+ */
+template<typename SrcExp, typename ValExp, typename IndexExp, typename DType>
+struct MatFillRowElementExp:
+      public Exp<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType>,
+                 DType, type::kChainer> {
+  /*! \brief src operand */
+  const SrcExp &src_;
+  const ValExp &val_;
+  /*! \brief index operand */
+  const IndexExp &index_;
+  /*! \brief constructor */
+  MatFillRowElementExp(const SrcExp &src, const ValExp &val, const IndexExp &index)
+      : src_(src), val_(val), index_(index) {}
+};
+
+template<typename SrcExp, typename ValExp, typename IndexExp,
+        typename SDType, typename VDType, typename IDType, int e1, int e2, int e3>
+inline MatFillRowElementExp<SrcExp, ValExp, IndexExp, SDType>
+mat_fill_row_element(const Exp<SrcExp, SDType, e1> &src,
+                     const Exp<ValExp, VDType, e2> &val,
+                     const Exp<IndexExp, IDType, e3> &index) {
+  TypeCheckPass<ExpInfo<SrcExp>::kDim == 2 && ExpInfo<ValExp>::kDim == 1 && ExpInfo<IndexExp>::kDim == 1>
+      ::Error_Expression_Does_Not_Meet_Dimension_Req();
+  return MatFillRowElementExp<SrcExp, ValExp, IndexExp, SDType>(src.self(), val.self(), index.self());
+}
+
+//----------------------
+// Execution plan
+//----------------------
+template<typename SrcExp, typename ValExp, typename IndexExp, typename DType>
+struct Plan<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType>, DType> {
+ public:
+  explicit Plan(const MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> &e)
+      : src_(MakePlan(e.src_)),
+        val_(MakePlan(e.val_)),
+        index_(MakePlan(e.index_)) {
+  }
+  MSHADOW_XINLINE DType Eval(index_t y, index_t x) const {
+    index_t idx = static_cast<index_t>(index_.Eval(0, y));
+    if(idx == x) {
+      return static_cast<DType>(val_.Eval(0, y));
+    }
+    else {
+      return static_cast<DType>(src_.Eval(y, x));
+    }
+  }
+
+ private:
+  expr::Plan<SrcExp, DType> src_;
+  expr::Plan<ValExp, DType> val_;
+  expr::Plan<IndexExp, DType> index_;
+};
+
+template<typename SrcExp, typename ValExp, typename IndexExp, typename DType>
+inline Plan<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType>, DType>
+MakePlan(const MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> &exp) {
+  return Plan<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType>, DType>(exp);
+}
+
+template<int dim, typename SrcExp, typename ValExp, typename IndexExp, typename DType>
+struct ShapeCheck<dim, MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> > {
+  inline static Shape<dim>
+  Check(const MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> &t) {
+    CHECK(dim == 2)
+        << "MatFillRowElementExp only support 2 dimension output";
+    Shape<2> shape_src = ShapeCheck<2, SrcExp>::Check(t.src_);
+    Shape<1> shape_val = ShapeCheck<1, ValExp>::Check(t.val_);
+    Shape<1> shape_index = ShapeCheck<1, IndexExp>::Check(t.index_);
+    CHECK((shape_src[0] == shape_index[0]) && (shape_index[0] == shape_val[0]))
+        << "mat_fill_row_element index vector length, val vector length and number of rows in matrix";
+    return shape_src;
+  }
+};
+
+template<typename SrcExp, typename ValExp, typename IndexExp, typename DType>
+struct ExpInfo<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> > {
+  static const int kDim = 2;
+  static const int kDevMask = ExpInfo<SrcExp>::kDevMask & ExpInfo<ValExp>::kDevMask & ExpInfo<IndexExp>::kDevMask;
+};
+}  // namespace expr
+}  // namespace mshadow
+#endif  // MSHADOW_EXTENSION_FILL_H_

From fa897bab4acf2ed5338f9bfb244b71a910409570 Mon Sep 17 00:00:00 2001
From: sxjscience <xshiab@ust.hk>
Date: Wed, 6 Jan 2016 14:27:16 +0800
Subject: [PATCH 2/2] Fix lint

---
 mshadow/extension/fill.h | 17 +++++++++--------
 1 file changed, 9 insertions(+), 8 deletions(-)

diff --git a/mshadow/extension/fill.h b/mshadow/extension/fill.h
index a7b60d258210..4ac62c1673e5 100644
--- a/mshadow/extension/fill.h
+++ b/mshadow/extension/fill.h
@@ -39,9 +39,10 @@ inline MatFillRowElementExp<SrcExp, ValExp, IndexExp, SDType>
 mat_fill_row_element(const Exp<SrcExp, SDType, e1> &src,
                      const Exp<ValExp, VDType, e2> &val,
                      const Exp<IndexExp, IDType, e3> &index) {
-  TypeCheckPass<ExpInfo<SrcExp>::kDim == 2 && ExpInfo<ValExp>::kDim == 1 && ExpInfo<IndexExp>::kDim == 1>
-      ::Error_Expression_Does_Not_Meet_Dimension_Req();
-  return MatFillRowElementExp<SrcExp, ValExp, IndexExp, SDType>(src.self(), val.self(), index.self());
+  TypeCheckPass<ExpInfo<SrcExp>::kDim == 2 && ExpInfo<ValExp>::kDim == 1
+                && ExpInfo<IndexExp>::kDim == 1>::Error_Expression_Does_Not_Meet_Dimension_Req();
+  return MatFillRowElementExp<SrcExp, ValExp, IndexExp, SDType>(src.self(),
+                                                                val.self(), index.self());
 }
 
 //----------------------
@@ -57,10 +58,9 @@ struct Plan<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType>, DType> {
   }
   MSHADOW_XINLINE DType Eval(index_t y, index_t x) const {
     index_t idx = static_cast<index_t>(index_.Eval(0, y));
-    if(idx == x) {
+    if (idx == x) {
       return static_cast<DType>(val_.Eval(0, y));
-    }
-    else {
+    } else {
       return static_cast<DType>(src_.Eval(y, x));
     }
   }
@@ -87,7 +87,7 @@ struct ShapeCheck<dim, MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> > {
     Shape<1> shape_val = ShapeCheck<1, ValExp>::Check(t.val_);
     Shape<1> shape_index = ShapeCheck<1, IndexExp>::Check(t.index_);
     CHECK((shape_src[0] == shape_index[0]) && (shape_index[0] == shape_val[0]))
-        << "mat_fill_row_element index vector length, val vector length and number of rows in matrix";
+        << "mat_fill_row_element index length, val length and number of rows in matrix";
     return shape_src;
   }
 };
@@ -95,7 +95,8 @@ struct ShapeCheck<dim, MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> > {
 template<typename SrcExp, typename ValExp, typename IndexExp, typename DType>
 struct ExpInfo<MatFillRowElementExp<SrcExp, ValExp, IndexExp, DType> > {
   static const int kDim = 2;
-  static const int kDevMask = ExpInfo<SrcExp>::kDevMask & ExpInfo<ValExp>::kDevMask & ExpInfo<IndexExp>::kDevMask;
+  static const int kDevMask =
+          ExpInfo<SrcExp>::kDevMask & ExpInfo<ValExp>::kDevMask & ExpInfo<IndexExp>::kDevMask;
 };
 }  // namespace expr
 }  // namespace mshadow