[mlpack-svn] r15484 - mlpack/trunk/src/mlpack/core/math

[fastlab-svn at coffeetalk-1.cc.gatech.edu]

Author: rcurtin
Date: Wed Jul 17 10:33:43 2013
New Revision: 15484

Log:
Simplify centering code.  Maybe it's faster?


Modified:
   mlpack/trunk/src/mlpack/core/math/lin_alg.cpp

Modified: mlpack/trunk/src/mlpack/core/math/lin_alg.cpp
==============================================================================
--- mlpack/trunk/src/mlpack/core/math/lin_alg.cpp	(original)
+++ mlpack/trunk/src/mlpack/core/math/lin_alg.cpp	Wed Jul 17 10:33:43 2013
@@ -37,13 +37,10 @@
  */
 void mlpack::math::Center(const arma::mat& x, arma::mat& xCentered)
 {
-  // Sum matrix along dimension 0 (that is, sum elements in each row).
-  arma::vec rowVectorSum = arma::sum(x, 1);
-  rowVectorSum /= x.n_cols; // scale
-
-  xCentered.set_size(x.n_rows, x.n_cols);
-  for (size_t i = 0; i < x.n_rows; i++)
-    xCentered.row(i) = x.row(i) - rowVectorSum(i);
+  // Get the mean of the elements in each row.
+  arma::vec rowMean = arma::sum(x, 1) / x.n_cols;
+
+  xCentered = x - arma::repmat(rowMean, 1, x.n_cols);
 }
 
 /**