core: vertical_segment: Fix 'get', 'data_view', and 'matrix_view'.

Partly fixes a regression introduced in f8843e56.
Reported by Laurent BELCOUR <laurent.belcour@gmail.com>
at <http://lists.gforge.inria.fr/pipermail/alta-devel/2017-January/000746.html>.

sources/core/common.h

 /* ALTA --- Analysis of Bidirectional Reflectance Distribution Functions
 
    Copyright (C) 2014 CNRS
-   Copyright (C) 2013, 2014, 2015, 2016 Inria
+   Copyright (C) 2013, 2014, 2015, 2016, 2017 Inria
 
    This file is part of ALTA.
 
@@ -38,6 +38,8 @@
 typedef Eigen::VectorXd vec;
 typedef Eigen::Ref<vec> vecref;
 typedef Eigen::Ref<const vec> const_vecref;
+typedef Eigen::Matrix<double, Eigen::Dynamic, Eigen::Dynamic, Eigen::RowMajor>
+    RowMatrixXd;
 
 // Convenience functions.
 static inline double norm(const vec& v)

sources/core/vertical_segment.cpp

@@ -142,7 +142,7 @@ void vertical_segment::get(int i, vec& yl, vec& yu) const
 
 vec vertical_segment::get(int i) const
 {
-    return data_view().col(i);
+    return data_view().row(i);
 }
 
 void vertical_segment::set(int i, const vec& x)

sources/core/vertical_segment.h

 /* ALTA --- Analysis of Bidirectional Reflectance Distribution Functions
 
-   Copyright (C) 2013, 2014, 2015, 2016 Inria
+   Copyright (C) 2013, 2014, 2015, 2016, 2017 Inria
 
    This file is part of ALTA.
 
@@ -164,20 +164,19 @@ class vertical_segment : public data
       // Thus, it has (dimX + dimY + N * dimY) columns, where N is between 0
       // and 2 depending on the confidence interval data available, and SIZE
       // rows.
-      Eigen::Map<Eigen::MatrixXd> matrix_view() const
+      Eigen::Map<RowMatrixXd> matrix_view() const
       {
-          return Eigen::Map<Eigen::MatrixXd>(_data.get(), size(),
-                                             column_number());
+          return Eigen::Map<RowMatrixXd>(_data.get(), size(), column_number());
       }
 
    private: // method
 
       //! \brief Return a matrix view of DATA that excludes confidence
       // interval data.  It has (dimX + dimY) columns and SIZE rows.
-      Eigen::Map<Eigen::MatrixXd, 0, Eigen::OuterStride<> > data_view() const
+      Eigen::Map<RowMatrixXd, 0, Eigen::OuterStride<> > data_view() const
       {
-          return Eigen::Map<Eigen::MatrixXd, 0, Eigen::OuterStride<> >
-              (_data.get(), _parameters.dimX() + _parameters.dimY(), size(),
+          return Eigen::Map<RowMatrixXd, 0, Eigen::OuterStride<> >
+              (_data.get(), _size, _parameters.dimX() + _parameters.dimY(),
                Eigen::OuterStride<>(column_number()));
       }
 

sources/tests/core/data-io.cpp

 /* ALTA --- Analysis of Bidirectional Reflectance Distribution Functions
 
-   Copyright (C) 2015, 2016 Inria
+   Copyright (C) 2015, 2016, 2017 Inria
 
    This file is part of ALTA.
 
@@ -23,6 +23,7 @@
 
 #include <string>
 #include <iostream>
+#include <sstream>
 
 #include <cstring>
 #include <cstdlib>
@@ -37,6 +38,49 @@
 
 using namespace alta;
 
+// Try loading a simple example from a text-format stream.
+static void test_simple_load_from_text()
+{
+    static const char example[] = "\
+#DIM 1 3f\n\
+#VS 0\n\
+#PARAM_IN COS_TH\n\
+#PARAM_OUT RGB_COLOR\n\
+0 1 2 3\n\
+4 5 6 7\n\
+8 9 10 11\n";
+
+    std::istringstream input(example);
+
+    auto data = dynamic_pointer_cast<vertical_segment>(
+        plugins_manager::load_data("vertical_segment", input));
+    TEST_ASSERT(data != NULL);
+
+    TEST_ASSERT(data->size() == 3);
+    TEST_ASSERT(data->parametrization().input_parametrization()
+                == params::COS_TH);
+    TEST_ASSERT(data->parametrization().output_parametrization()
+                == params::RGB_COLOR);
+
+    // Currently we always get ASYMMETRICAL_CONFIDENCE_INTERVAL for backward
+    // compatibility reasons.
+    TEST_ASSERT(data->confidence_interval_kind()
+                == vertical_segment::ASYMMETRICAL_CONFIDENCE_INTERVAL);
+
+    TEST_ASSERT(data->get(0) == Eigen::Vector4d(0., 1., 2., 3.));
+    TEST_ASSERT(data->get(1) == Eigen::Vector4d(4., 5., 6., 7.));
+    TEST_ASSERT(data->get(2) == Eigen::Vector4d(8., 9., 10., 11.));
+
+    // The "matrix view" includes confidence interval data.
+    auto view = data->matrix_view();
+    TEST_ASSERT(view.cols() == 1 + 3 + 2 * 3);
+    TEST_ASSERT(view.rows() == 3);
+    TEST_ASSERT(view.col(0) == Eigen::Vector3d(0., 4., 8.));
+    TEST_ASSERT(view.col(1) == Eigen::Vector3d(1., 5., 9.));
+    TEST_ASSERT(view.col(2) == Eigen::Vector3d(2., 6., 10.));
+    TEST_ASSERT(view.col(3) == Eigen::Vector3d(3., 7., 11.));
+}
+
 // Files that are automatically deleted upon destruction.
 class temporary_file
 {
@@ -116,6 +160,10 @@ int main(int argc, char** argv)
         input_file = data_dir + "/" + data_file;
     }
 
+    // Simple test first.
+    test_simple_load_from_text();
+
+    // Try a sequence of loads and saves.
     try
     {
         std::ifstream input;