From ff85575b28923f55e12aa61bc9668f84a3608682 Mon Sep 17 00:00:00 2001
From: Mathieu Barnachon <mathieu.barnachon@gmail.com>
Date: Mon, 5 Aug 2013 12:06:55 +1200
Subject: [PATCH] Adding read/write functions to PCA class. Update PCA test.

---
 modules/core/include/opencv2/core.hpp |  4 ++++
 modules/core/src/matmul.cpp           | 21 +++++++++++++++++++++
 modules/core/test/test_mat.cpp        | 26 ++++++++++++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/modules/core/include/opencv2/core.hpp b/modules/core/include/opencv2/core.hpp
index 9833315d5..c7f07ed45 100644
--- a/modules/core/include/opencv2/core.hpp
+++ b/modules/core/include/opencv2/core.hpp
@@ -670,6 +670,10 @@ public:
     //! reconstructs the original vector from the projection
     void backProject(InputArray vec, OutputArray result) const;
 
+    //! write and load PCA matrix
+    void write(FileStorage& fs ) const;
+    void read(const FileNode& fs);
+
     Mat eigenvectors; //!< eigenvectors of the covariation matrix
     Mat eigenvalues; //!< eigenvalues of the covariation matrix
     Mat mean; //!< mean value subtracted before the projection and added after the back projection
diff --git a/modules/core/src/matmul.cpp b/modules/core/src/matmul.cpp
index 404c5b434..b3aadebbd 100644
--- a/modules/core/src/matmul.cpp
+++ b/modules/core/src/matmul.cpp
@@ -2896,6 +2896,27 @@ PCA& PCA::operator()(InputArray _data, InputArray __mean, int flags, int maxComp
     return *this;
 }
 
+void PCA::write(FileStorage& fs ) const
+{
+    CV_Assert( fs.isOpened() );
+
+    fs << "name" << "PCA";
+    fs << "vectors" << eigenvectors;
+    fs << "values" << eigenvalues;
+    fs << "mean" << mean;
+}
+
+void PCA::read(const FileNode& fs)
+{
+    CV_Assert( !fs.empty() );
+    String name = (String)fs["name"];
+    CV_Assert( name == "PCA" );
+
+    cv::read(fs["vectors"], eigenvectors);
+    cv::read(fs["values"], eigenvalues);
+    cv::read(fs["mean"], mean);
+}
+
 template <typename T>
 int computeCumulativeEnergy(const Mat& eigenvalues, double retainedVariance)
 {
diff --git a/modules/core/test/test_mat.cpp b/modules/core/test/test_mat.cpp
index 245347b8b..6e3ec03dc 100644
--- a/modules/core/test/test_mat.cpp
+++ b/modules/core/test/test_mat.cpp
@@ -510,6 +510,32 @@ protected:
             return;
         }
     #endif
+        // Test read and write
+        FileStorage fs( "PCA_store.yml", FileStorage::WRITE );
+        rPCA.write( fs );
+        fs.release();
+
+        PCA lPCA;
+        fs.open( "PCA_store.yml", FileStorage::READ );
+        lPCA.read( fs.root() );
+        err = norm( rPCA.eigenvectors, lPCA.eigenvectors, CV_RELATIVE_L2 );
+        if( err > 0 )
+        {
+            ts->printf( cvtest::TS::LOG, "bad accuracy of write/load functions (YML); err = %f\n", err );
+            ts->set_failed_test_info( cvtest::TS::FAIL_BAD_ACCURACY );
+        }
+        err = norm( rPCA.eigenvalues, lPCA.eigenvalues, CV_RELATIVE_L2 );
+        if( err > 0 )
+        {
+            ts->printf( cvtest::TS::LOG, "bad accuracy of write/load functions (YML); err = %f\n", err );
+            ts->set_failed_test_info( cvtest::TS::FAIL_BAD_ACCURACY );
+        }
+        err = norm( rPCA.mean, lPCA.mean, CV_RELATIVE_L2 );
+        if( err > 0 )
+        {
+            ts->printf( cvtest::TS::LOG, "bad accuracy of write/load functions (YML); err = %f\n", err );
+            ts->set_failed_test_info( cvtest::TS::FAIL_BAD_ACCURACY );
+        }
     }
 };