From 509ae79a5de846dfd38bd85618b2467066413a97 Mon Sep 17 00:00:00 2001
From: wangmeng28 <wangmeng28@baidu.com>
Date: Thu, 26 Oct 2017 00:47:06 +0800
Subject: [PATCH] Add rowScale for CpuSparseMatrix

---
 paddle/math/CpuSparseMatrix.cpp | 17 +++++++++++++++++
 paddle/math/CpuSparseMatrix.h   |  9 +++++++++
 2 files changed, 26 insertions(+)

diff --git a/paddle/math/CpuSparseMatrix.cpp b/paddle/math/CpuSparseMatrix.cpp
index bf62229c03b..e211c23a7e6 100644
--- a/paddle/math/CpuSparseMatrix.cpp
+++ b/paddle/math/CpuSparseMatrix.cpp
@@ -260,6 +260,23 @@ void CpuSparseMatrix::printOneRow(std::ostream& os, size_t idx) const {
   os << ";";
 }
 
+void CpuSparseMatrix::rowScale(size_t cCol, CpuSparseMatrix& b, Matrix& c) {
+  CHECK(getFormat() != SPARSE_CSC) << "Not supported";
+  CHECK(height_ == b.getHeight());
+  CHECK(width_ == b.getWidth());
+  real* A = getValue();
+  real* B = b.getValue();
+  for (size_t i = 0; i < height_; i++) {
+    size_t start = getRowStartIdx(i);
+    size_t end = getRowStartIdx(i + 1);
+    CHECK(start == b.getRowStartIdx(i));
+    CHECK(end == b.getRowStartIdx(i + 1));
+    for (size_t j = start; j < end; j++) {
+      A[j] = B[j] * c.getElement(i, cCol);
+    }
+  }
+}
+
 void CpuSparseMatrix::randomizeUniform() {
   CHECK_LE(elementCnt_, height_ * width_);
   if (valueType_ == FLOAT_VALUE) {
diff --git a/paddle/math/CpuSparseMatrix.h b/paddle/math/CpuSparseMatrix.h
index 36d57bbb652..8f9ad67215f 100644
--- a/paddle/math/CpuSparseMatrix.h
+++ b/paddle/math/CpuSparseMatrix.h
@@ -236,6 +236,15 @@ public:
               const unsigned int* cols,
               const real* values);
 
+  /**
+   * @brief this_row = b_row * c_row[cCol]
+   *
+   * @param[in]  cCol   the column of matrix c used to scale each row of b
+   * @param[in]  b      CpuSparseMatrix
+   * @param[in]  c      Matrix
+   */
+  void rowScale(size_t cCol, CpuSparseMatrix& b, Matrix& c);
+
   void randomizeUniform();
 
   void copyFrom(const GpuSparseMatrix& src, hl_stream_t stream);
-- 
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