diff --git a/openbr/core/bee.cpp b/openbr/core/bee.cpp
index a429f92..a5a0030 100644
--- a/openbr/core/bee.cpp
+++ b/openbr/core/bee.cpp
@@ -111,25 +111,27 @@ void BEE::writeSigset(const QString &sigset, const br::FileList &files, bool ign
     lines.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
     lines.append("<biometric-signature-set>");
     foreach (const File &file, files) {
-        QStringList metadata;
-        if (!ignoreMetadata) {
-            foreach (const QString &key, file.localKeys()) {
-                if ((key == "Index") || (key == "Label") || (key == "Points") || (key == "Rects")) continue;
-                metadata.append(key+"=\""+QtUtils::toString(file.value(key))+"\"");
-            }
-            QStringList landmarks;
-            if (!file.points().isEmpty()) {
-                foreach (const QPointF &point, file.points()) landmarks.append(QtUtils::toString(point));
-                metadata.append("Points=\"["+landmarks.join(",")+"]\""); landmarks.clear();
-            }
-            if (!file.rects().isEmpty()) {
-                foreach (const QRectF &rect, file.rects()) landmarks.append(QtUtils::toString(rect));
-                metadata.append("Rects=\"["+landmarks.join(",")+"]\"");
+        if (!file.isNull()) {
+            QStringList metadata;
+            if (!ignoreMetadata) {
+                foreach (const QString &key, file.localKeys()) {
+                    if ((key == "Index") || (key == "Label") || (key == "Points") || (key == "Rects")) continue;
+                    metadata.append(key+"=\""+QtUtils::toString(file.value(key))+"\"");
+                }
+                QStringList landmarks;
+                if (!file.points().isEmpty()) {
+                    foreach (const QPointF &point, file.points()) landmarks.append(QtUtils::toString(point));
+                    metadata.append("Points=\"["+landmarks.join(",")+"]\""); landmarks.clear();
+                }
+                if (!file.rects().isEmpty()) {
+                    foreach (const QRectF &rect, file.rects()) landmarks.append(QtUtils::toString(rect));
+                    metadata.append("Rects=\"["+landmarks.join(",")+"]\"");
+                }
             }
+            lines.append("\t<biometric-signature name=\"" + file.get<QString>("Label",file.baseName()) +"\">");
+            lines.append("\t\t<presentation file-name=\"" + file.name + "\" " + metadata.join(" ") + "/>");
+            lines.append("\t</biometric-signature>");
         }
-        lines.append("\t<biometric-signature name=\"" + file.get<QString>("Label",file.baseName()) +"\">");
-        lines.append("\t\t<presentation file-name=\"" + file.name + "\" " + metadata.join(" ") + "/>");
-        lines.append("\t</biometric-signature>");
     }
     lines.append("</biometric-signature-set>");
     QtUtils::writeFile(sigset, lines);
diff --git a/openbr/plugins/eigen3.cpp b/openbr/plugins/eigen3.cpp
index 73fd678..4965d2f 100644
--- a/openbr/plugins/eigen3.cpp
+++ b/openbr/plugins/eigen3.cpp
@@ -15,6 +15,7 @@
  * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
 
 #include <Eigen/Dense>
+
 #include "openbr_internal.h"
 
 #include "openbr/core/common.h"
@@ -25,6 +26,24 @@ namespace br
 {
 
 /*!
+ * \ingroup initializers
+ * \brief Initialize Eigen
+ * http://eigen.tuxfamily.org/dox/TopicMultiThreading.html
+ * \author Scott Klum \cite sklum
+ */
+class EigenInitializer : public Initializer
+{
+    Q_OBJECT
+
+    void initialize() const
+    {
+        Eigen::initParallel();
+    }
+};
+
+BR_REGISTER(Initializer, EigenInitializer)
+
+/*!
  * \ingroup transforms
  * \brief Projects input into learned Principal Component Analysis subspace.
  * \author Brendan Klare \cite bklare
@@ -508,6 +527,7 @@ class LDATransform : public Transform
 
     void store(QDataStream &stream) const
     {
+        stream << pcaKeep;
         stream << directLDA;
         stream << directDrop;
         stream << dimsOut;
@@ -519,6 +539,7 @@ class LDATransform : public Transform
 
     void load(QDataStream &stream)
     {
+        stream >> pcaKeep;
         stream >> directLDA;
         stream >> directDrop;
         stream >> dimsOut;
diff --git a/openbr/plugins/gui.cpp b/openbr/plugins/gui.cpp
index 557ac9c..2e614a2 100644
--- a/openbr/plugins/gui.cpp
+++ b/openbr/plugins/gui.cpp
@@ -413,13 +413,13 @@ private:
 
 };
 
-class DisplayGUI : public QMainWindow
+class GUIWindow : public QMainWindow
 {
     Q_OBJECT
 
 public:
 
-    DisplayGUI(QWidget * parent = NULL) : QMainWindow(parent)
+    GUIWindow(QWidget * parent = NULL) : QMainWindow(parent)
     {
         centralWidget = new QWidget();
         layout = new QHBoxLayout();
@@ -592,8 +592,10 @@ public:
     template<typename WindowType>
     void initActual()
     {
-        if (!Globals->useGui)
+        if (!Globals->useGui) {
+            qWarning("GUI transform %s created without enabling GUI support.\nRun \"br -gui ...\" to enable GUI support from the command line, or set\nGlobals->useGui to true.", this->metaObject()->className());
             return;
+        }
 
         if (displayBuffer)
             delete displayBuffer;
@@ -795,7 +797,7 @@ class ElicitTransform : public ShowTransform
 
     Q_OBJECT
 
-    DisplayGUI *gui;
+    GUIWindow *gui;
 
 public:
     ElicitTransform() : ShowTransform()
@@ -835,14 +837,16 @@ public:
 
     void init()
     {
-        initActual<DisplayGUI>();
+        initActual<GUIWindow>();
     }
 
     template<typename GUIType>
     void initActual()
     {
-        if (!Globals->useGui)
+        if (!Globals->useGui) {
+            qWarning("GUI transform %s created without enabling GUI support.\nRun \"br -gui ...\" to enable GUI support from the command line, or set\nGlobals->useGui to true.", this->metaObject()->className());
             return;
+        }
 
         TimeVaryingTransform::init();
 
diff --git a/openbr/plugins/independent.cpp b/openbr/plugins/independent.cpp
index 7781b74..59c7fb5 100644
--- a/openbr/plugins/independent.cpp
+++ b/openbr/plugins/independent.cpp
@@ -9,13 +9,14 @@ using namespace cv;
 namespace br
 {
 
-static TemplateList Downsample(const TemplateList &templates, int classes, int instances, float fraction, const QString & inputVariable, const QStringList &gallery)
+static TemplateList Downsample(const TemplateList &templates, int classes, int instances, float fraction, const QString & inputVariable, const QStringList &gallery, const QStringList &subjects)
 {
     // Return early when no downsampling is required
     if ((classes == std::numeric_limits<int>::max()) &&
             (instances == std::numeric_limits<int>::max()) &&
             (fraction >= 1) &&
-            (gallery.isEmpty()))
+            (gallery.isEmpty()) &&
+            (subjects.isEmpty()))
         return templates;
 
     const bool atLeast = instances < 0;
@@ -66,6 +67,11 @@ static TemplateList Downsample(const TemplateList &templates, int classes, int i
             if (!gallery.contains(downsample[i].file.get<QString>("Gallery")))
                 downsample.removeAt(i);
 
+    if (!subjects.isEmpty())
+        for (int i=downsample.size()-1; i>=0; i--)
+            if (subjects.contains(downsample[i].file.get<QString>(inputVariable)))
+                downsample.removeAt(i);
+
     return downsample;
 }
 
@@ -78,12 +84,15 @@ class DownsampleTrainingTransform : public Transform
     Q_PROPERTY(float fraction READ get_fraction WRITE set_fraction RESET reset_fraction STORED false)
     Q_PROPERTY(QString inputVariable READ get_inputVariable WRITE set_inputVariable RESET reset_inputVariable STORED false)
     Q_PROPERTY(QStringList gallery READ get_gallery WRITE set_gallery RESET reset_gallery STORED false)
+    Q_PROPERTY(QStringList subjects READ get_subjects WRITE set_subjects RESET reset_subjects STORED false)
     BR_PROPERTY(br::Transform*, transform, NULL)
     BR_PROPERTY(int, classes, std::numeric_limits<int>::max())
     BR_PROPERTY(int, instances, std::numeric_limits<int>::max())
     BR_PROPERTY(float, fraction, 1)
     BR_PROPERTY(QString, inputVariable, "Label")
     BR_PROPERTY(QStringList, gallery, QStringList())
+    BR_PROPERTY(QStringList, subjects, QStringList())
+
 
     void project(const Template & src, Template & dst) const
     {
@@ -96,7 +105,7 @@ class DownsampleTrainingTransform : public Transform
         if (!transform || !transform->trainable)
             return;
 
-        TemplateList downsampled = Downsample(data, classes, instances, fraction, inputVariable, gallery);
+        TemplateList downsampled = Downsample(data, classes, instances, fraction, inputVariable, gallery, subjects);
 
         transform->train(downsampled);
     }