add moving variance

plotjuggler_app/CMakeLists.txt

@@ -29,6 +29,7 @@ QT5_WRAP_UI ( UI_SRC
 
     transforms/first_derivative.ui
     transforms/moving_average_filter.ui
+    transforms/moving_variance.ui
     transforms/moving_rms.ui
     transforms/outlier_removal.ui
     transforms/integral_transform.ui
@@ -79,6 +80,7 @@ SET( PLOtJUGGLER_SRC
     transforms/lua_custom_function.cpp
     transforms/moving_average_filter.cpp
     transforms/moving_rms.cpp
+    transforms/moving_variance.cpp
     transforms/outlier_removal.cpp
     transforms/integral_transform.cpp
     transforms/absolute_transform.cpp

plotjuggler_app/main.cpp

@@ -23,6 +23,7 @@
 #include "transforms/first_derivative.h"
 #include "transforms/scale_transform.h"
 #include "transforms/moving_average_filter.h"
+#include "transforms/moving_variance.h"
 #include "transforms/moving_rms.h"
 #include "transforms/outlier_removal.h"
 #include "transforms/integral_transform.h"
@@ -217,11 +218,12 @@ int main(int argc, char* argv[])
   TransformFactory::registerTransform<OutlierRemovalFilter>();
   TransformFactory::registerTransform<IntegralTransform>();
   TransformFactory::registerTransform<AbsoluteTransform>();
+  TransformFactory::registerTransform<MovingVarianceFilter>();
   //---------------------------
 
   QCommandLineParser parser;
-  parser.setApplicationDescription("PlotJuggler: the time series visualization tool that "
-                                   "you deserve ");
+  parser.setApplicationDescription("PlotJuggler: the time series visualization"
+                                   " tool that you deserve ");
   parser.addVersionOption();
   parser.addHelpOption();
 

plotjuggler_app/transforms/moving_variance.cpp

@@ -0,0 +1,95 @@
+#include "moving_variance.h"
+#include "ui_moving_variance.h"
+#include <QCheckBox>
+
+MovingVarianceFilter::MovingVarianceFilter()
+  : ui(new Ui::MovingVarianceFilter)
+  , _widget(new QWidget())
+  , _buffer(1)
+  , _ring_view(_buffer.begin(), _buffer.end())
+{
+  ui->setupUi(_widget);
+
+  connect(ui->spinBoxSamples, qOverload<int>(&QSpinBox::valueChanged), this,
+          [=](int) { emit parametersChanged(); });
+
+  connect(ui->checkBoxStdDev, &QCheckBox::toggled, this,
+          [=]() { emit parametersChanged(); });
+}
+
+MovingVarianceFilter::~MovingVarianceFilter()
+{
+  delete ui;
+  delete _widget;
+}
+
+void MovingVarianceFilter::reset()
+{
+  _buffer.clear();
+  TransformFunction_SISO::reset();
+}
+
+std::optional<PlotData::Point> MovingVarianceFilter::calculateNextPoint(size_t index)
+{
+  size_t buffer_size =
+      std::min(size_t(ui->spinBoxSamples->value()), size_t(dataSource()->size()));
+  if (buffer_size != _buffer.size())
+  {
+    _buffer.resize(buffer_size);
+    _ring_view = nonstd::ring_span<PlotData::Point>(_buffer.begin(), _buffer.end());
+  }
+
+  const auto& p = dataSource()->at(index);
+  _ring_view.push_back(p);
+
+  while (_ring_view.size() < buffer_size)
+  {
+    _ring_view.push_back(p);
+  }
+
+  double total = 0;
+  for (const auto& point: _ring_view)
+  {
+    total += point.y;
+  }
+  const double N = double(_ring_view.size());
+  const double avg = total / N;
+
+  double total_sqr = 0;
+  for (const auto& point: _ring_view)
+  {
+    const auto v = point.y - avg;
+    total_sqr += v*v;
+  }
+
+  if(ui->checkBoxStdDev->isChecked())
+  {
+    return PlotData::Point{ p.x, std::sqrt(total_sqr / N)};
+  }
+  return PlotData::Point{ p.x, total_sqr / N};
+}
+
+QWidget* MovingVarianceFilter::optionsWidget()
+{
+  return _widget;
+}
+
+bool MovingVarianceFilter::xmlSaveState(QDomDocument& doc,
+                                       QDomElement& parent_element) const
+{
+  QDomElement widget_el = doc.createElement("options");
+  widget_el.setAttribute("value", ui->spinBoxSamples->value());
+  widget_el.setAttribute("apply_sqrt",
+                         ui->checkBoxStdDev->isChecked() ? "true" : "false");
+  parent_element.appendChild(widget_el);
+  return true;
+}
+
+bool MovingVarianceFilter::xmlLoadState(const QDomElement& parent_element)
+{
+  QDomElement widget_el = parent_element.firstChildElement("options");
+  ui->spinBoxSamples->setValue(widget_el.attribute("value").toInt());
+  bool checked = widget_el.attribute("apply_sqrt") == "true";
+  ui->checkBoxStdDev->setChecked(checked);
+  return true;
+}

plotjuggler_app/transforms/moving_variance.h

@@ -0,0 +1,44 @@
+#pragma once
+
+#include <QRadioButton>
+#include <QSpinBox>
+#include <QDoubleSpinBox>
+#include "PlotJuggler/transform_function.h"
+#include "ui_moving_variance.h"
+#include "PlotJuggler/ring_span.hpp"
+
+using namespace PJ;
+
+namespace Ui
+{
+class MovingVarianceFilter;
+}
+
+class MovingVarianceFilter : public TransformFunction_SISO
+{
+public:
+  explicit MovingVarianceFilter();
+
+  ~MovingVarianceFilter() override;
+
+  void reset() override;
+
+  const char* name() const override
+  {
+    return "Moving Variance";
+  }
+
+  QWidget* optionsWidget() override;
+
+  bool xmlSaveState(QDomDocument& doc, QDomElement& parent_element) const override;
+
+  bool xmlLoadState(const QDomElement& parent_element) override;
+
+private:
+  Ui::MovingVarianceFilter* ui;
+  QWidget* _widget;
+  std::vector<PlotData::Point> _buffer;
+  nonstd::ring_span_lite::ring_span<PlotData::Point> _ring_view;
+
+  std::optional<PlotData::Point> calculateNextPoint(size_t index) override;
+};

plotjuggler_app/transforms/moving_variance.ui

@@ -0,0 +1,90 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>MovingVarianceFilter</class>
+ <widget class="QWidget" name="MovingVarianceFilter">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>425</width>
+    <height>300</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Form</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <widget class="QLabel" name="label">
+     <property name="font">
+      <font>
+       <bold>true</bold>
+      </font>
+     </property>
+     <property name="text">
+      <string>Select the size of the window</string>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <layout class="QFormLayout" name="formLayout">
+     <item row="0" column="1">
+      <widget class="QSpinBox" name="spinBoxSamples">
+       <property name="maximumSize">
+        <size>
+         <width>100</width>
+         <height>16777215</height>
+        </size>
+       </property>
+       <property name="minimum">
+        <number>1</number>
+       </property>
+       <property name="maximum">
+        <number>1000</number>
+       </property>
+       <property name="value">
+        <number>10</number>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="0">
+      <widget class="QLabel" name="label_2">
+       <property name="text">
+        <string>Window size:</string>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QCheckBox" name="checkBoxStdDev">
+     <property name="text">
+      <string>Apply square root</string>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <widget class="QLabel" name="label_3">
+     <property name="text">
+      <string>(i.e., convert to standard deviation)</string>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <spacer name="verticalSpacer">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="sizeHint" stdset="0">
+      <size>
+       <width>20</width>
+       <height>40</height>
+      </size>
+     </property>
+    </spacer>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>