diff options
Diffstat (limited to 'stats/statsview.cpp')
| -rw-r--r-- | stats/statsview.cpp | 76 |
1 files changed, 46 insertions, 30 deletions
diff --git a/stats/statsview.cpp b/stats/statsview.cpp index 5583643d7..405677e56 100644 --- a/stats/statsview.cpp +++ b/stats/statsview.cpp @@ -723,13 +723,14 @@ void StatsView::QuartileMarker::updatePosition() x + quartileMarkerSize / 2.0, y); } -StatsView::RegressionLine::RegressionLine(double a, double b, QPen pen, QGraphicsScene *scene, StatsAxis *xAxis, StatsAxis *yAxis) : - item(createItemPtr<QGraphicsLineItem>(scene)), +StatsView::RegressionLine::RegressionLine(double a, double b, double width, QBrush brush, QGraphicsScene *scene, StatsAxis *xAxis, StatsAxis *yAxis) : + item(createItemPtr<QGraphicsPolygonItem>(scene)), xAxis(xAxis), yAxis(yAxis), - a(a), b(b) + a(a), b(b), width(width) { item->setZValue(ZValues::chartFeatures); - item->setPen(pen); + item->setPen(Qt::NoPen); + item->setBrush(brush); } void StatsView::RegressionLine::updatePosition() @@ -738,21 +739,16 @@ void StatsView::RegressionLine::updatePosition() return; auto [minX, maxX] = xAxis->minMax(); auto [minY, maxY] = yAxis->minMax(); - double y1 = a * minX + b; - double y2 = a * maxX + b; - - // If not fully inside drawing region, do clipping. - if ((y1 < minY || y1 > maxY || y2 < minY || y2 > maxY) && fabs(a) > 0.0001) { - // Intersections with y = minY and y = maxY lines - double intersect_x1 = (minY - b) / a; - double intersect_x2 = (maxY - b) / a; - if (intersect_x1 > intersect_x2) - std::swap(intersect_x1, intersect_x2); - minX = std::max(minX, intersect_x1); - maxX = std::min(maxX, intersect_x2); - } - item->setLine(xAxis->toScreen(minX), yAxis->toScreen(a * minX + b), - xAxis->toScreen(maxX), yAxis->toScreen(a * maxX + b)); + + QPolygonF poly; + poly << QPointF(xAxis->toScreen(minX), yAxis->toScreen(a * minX + b + width)) + << QPointF(xAxis->toScreen(maxX), yAxis->toScreen(a * maxX + b + width)) + << QPointF(xAxis->toScreen(maxX), yAxis->toScreen(a * maxX + b - width)) + << QPointF(xAxis->toScreen(minX), yAxis->toScreen(a * minX + b - width)) + << QPointF(xAxis->toScreen(minX), yAxis->toScreen(a * minX + b + width)); + QRectF box(QPoint(xAxis->toScreen(minX), yAxis->toScreen(minY)), QPoint(xAxis->toScreen(maxX), yAxis->toScreen(maxY))); + + item->setPolygon(poly.intersected(box)); } StatsView::HistogramMarker::HistogramMarker(double val, bool horizontal, QPen pen, QGraphicsScene *scene, StatsAxis *xAxis, StatsAxis *yAxis) : @@ -784,9 +780,15 @@ void StatsView::addHistogramMarker(double pos, const QPen &pen, bool isHorizonta histogramMarkers.emplace_back(pos, isHorizontal, pen, &scene, xAxis, yAxis); } -void StatsView::addLinearRegression(double a, double b, double minX, double maxX, double minY, double maxY, StatsAxis *xAxis, StatsAxis *yAxis) +void StatsView::addLinearRegression(double a, double b, double res2, double r2, double minX, double maxX, double minY, double maxY, StatsAxis *xAxis, StatsAxis *yAxis) { - regressionLines.emplace_back(a, b, QPen(Qt::red), &scene, xAxis, yAxis); + QColor red = QColor(Qt::red); + red.setAlphaF(r2); + QPen pen(red); + QBrush brush(red); + brush.setStyle(Qt::SolidPattern); + + regressionLines.emplace_back(a, b, sqrt(res2), brush, &scene, xAxis, yAxis); } // Yikes, we get our data in different kinds of (bin, value) pairs. @@ -1025,12 +1027,21 @@ static bool is_linear_regression(int sample_size, double cov, double sx2, double return true; // can't happen, as we tested for sample_size above. } -// Returns the coefficients [a,b] of the line y = ax + b -// If case of an undetermined regression or one with infinite slope, returns [nan, nan] -static std::pair<double, double> linear_regression(const std::vector<StatsScatterItem> &v) +struct regression_data { + double a,b; + double res2, r2; +}; + +// Returns the coefficients a,b of the line y = ax + b +// as well as the variance of the residuals (averaged residual squared) as res2 +// and r^2 = 1.0 - variance of data / res2 which is the fraction of the variance of +// the data that is explained by the linear regression. +// If case of an undetermined regression or one with infinite slope, returns {nan, nan, 0.0, 0.0} + +static struct regression_data linear_regression(const std::vector<StatsScatterItem> &v) { if (v.size() < 2) - return { NaN, NaN }; + return { .a = NaN, .b = NaN, .res2 = 0.0, .r2 = 0.0}; // First, calculate the x and y average double avg_x = 0.0, avg_y = 0.0; @@ -1051,10 +1062,15 @@ static std::pair<double, double> linear_regression(const std::vector<StatsScatte bool is_linear = is_linear_regression((int)v.size(), cov, sx2, sy2); if (fabs(sx2) < 1e-10 || !is_linear) // If t is not statistically significant, do not plot the regression line. - return { NaN, NaN }; + return { .a = NaN, .b = NaN, .res2 = 0.0, .r2 = 0.0}; double a = cov / sx2; double b = avg_y - a * avg_x; - return { a, b }; + + double res2 = 0.0; + for (auto [x, y, d]: v) + res2 += (y - a * x - b) * (y - a * x - b); + double r2 = sy2 > 0.0 ? 1.0 - res2 / sy2 : 1.0; + return { .a = a, .b = b, .res2 = res2 / v.size(), .r2 = r2 }; } void StatsView::plotScatter(const std::vector<dive *> &dives, const StatsVariable *categoryVariable, const StatsVariable *valueVariable) @@ -1084,10 +1100,10 @@ void StatsView::plotScatter(const std::vector<dive *> &dives, const StatsVariabl series->append(dive, x, y); // y = ax + b - auto [a, b] = linear_regression(points); - if (!std::isnan(a)) { + struct regression_data reg = linear_regression(points); + if (!std::isnan(reg.a)) { auto [minx, maxx] = axisX->minMax(); auto [miny, maxy] = axisY->minMax(); - addLinearRegression(a, b, minx, maxx, miny, maxy, xAxis, yAxis); + addLinearRegression(reg.a, reg.b, reg.res2, reg.r2, minx, maxx, miny, maxy, xAxis, yAxis); } } |