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QuaScript

Polynomial Regression Channel

NewFree

Quadratic regression channel: acceleration and roll-overs

Trendlines & LevelsPrice overlay WebGPU CanvasHybridGradient fillDashboardLinesSignalsAlerts
quascriptlevelsregressionpolynomialcurvaturechannel

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Language
QuaScript
Engine
Native C++, incremental on live ticks
Rendering
WebGPU + Canvas
Placement
Price overlay
Settings
4
Plots
3
Lines of code
90
Source
presets/analysis/levels/polynomial_regression_channel.qs
Polynomial Regression Channelengine result
Loading the engine result…
quatick-charts · QuaScript engine on synthetic 1-minute bars · drag to pan · scroll to zoom · Run executes the script on the engine (⌘/Ctrl+Enter while editing)

About

A quadratic least-squares fit of price over the window, drawn as a curved channel with residual bands and a short projection. A straight regression cannot show a trend that is accelerating or rolling over; the quadratic term can. On history, the end point of the fit is drawn bar by bar, coloured by its curvature: sky when the trend is accelerating up or decelerating down (positive curvature), amber when it is accelerating down or rolling over (negative). Reading: a curvature flip while the slope still points the old way is the earliest sign of a turn; touches of the outer band against the curvature are exhaustion. Signals: curvature flips and outer-band rejections. Method: ordinary least squares on 1, x, x squared.

3
Plotted series
4
Signal marks
2
Drawings
1
Alert rules
4
Settings
79
Lines of code

What it draws

Price overlay · counted from the engine's plot table and the script's draw calls

Series

  • Line3
    Fit end
  • Band fills (render.band calls)2
Legend
Fit end Upper band Lower band

Signal marks

Curvature turns upCurvature turns downUpper band rejectionLower band rejection

Drawings and chart effects

  • Dashboard tables1 created
  • Paths1 created

How it runs

From source to the live chart, for this script

  1. 1
    Compile

    The QuaScript compiler checks the 90-line script (79 lines of code) and lowers it for the native C++ engine. Compile errors point at the exact line and column.

  2. 2
    Place

    The header sets overlay = true, so everything is drawn on the price chart, on the same scale as the candles.

  3. 3
    Compute

    The script runs once per bar, oldest to newest. Each bar also runs 5 loops (5 for). 2 persist variables keep state (objects, counters) across bars.

  4. 4
    Stay live

    On the terminal the script keeps one live engine session: a tick rolls the forming bar back to its checkpoint and re-executes only that bar, and new bars are appended, so history is never rerun while the market moves. The live result is identical to a full run.

  5. 5
    Render

    The results are handed to the chart: series on WebGPU, drawings on the Canvas 2D QuaScript layer.

  6. 6
    Tune

    4 settings in 2 groups appear in the chart's settings dialog. Changing one reruns the engine with the new value.

Rendering

Hybrid: this script draws on 2 surfaces at once

WebGPUSeries renderer

The browser's modern GPU API. The chart uploads every line, band and mark of the script as GPU buffers and draws them in one pass, so dense heatmaps and dozens of series stay smooth while you pan and zoom. Without WebGPU support the chart's GPU layer falls back to WebGL 2, then Canvas 2D.

In this script
  • • 3 plotted series
  • • 2 band fill calls
  • • 4 signal mark types

Chosen by render = webgpu in the header.

WebGLNot used

GPU drawing through WebGL 2, available in every current browser. Used for chart-native profiles and for series that ask for it with backend = "webgl". Fast for large numbers of bars and wide fills.

CanvasUsed

The browser's 2D drawing API. Text-heavy and object-style output (dashboard tables, zones, tags, segments), candle colors and backgrounds are painted by the QuaScript layer, a Canvas 2D surface over the chart. Series use Canvas when the script's header does not ask for a GPU.

In this script
  • • 1 dashboard tables (QuaScript layer)
  • • 1 paths (QuaScript layer)

Alerts

1 alert rule declared with alert.rule

Curvature flip

The quadratic fit changed curvature

Settings

4 settings, grouped as in the chart's settings dialog

Fit
SettingTypeDefaultRange / optionsId
Window barsInteger15020 – 1000window_bars
Band (sigma)Number20.5 – 5, step 0.05band_sigma
Projection barsInteger150 – 100projection_bars
Drawing
SettingTypeDefaultRange / optionsId
Curve point everyInteger31 – 20curve_point_every

Script

packages/quascript/presets/analysis/levels/polynomial_regression_channel.qs

Header

analysis "Polynomial Regression Channel" {
    overlay = true
    render = webgpu
    short_title = PRC
    max_objects = 20
}
Total lines
90
Code lines
79
Comment lines
10
Helper functions
0
Loops
5
Persistent variables
2
Higher-interval feeds
0
Engine plots
3

Built with

Lists (list.*)
list.clearlist.createlist.push
Math (math.*)
math.coalescemath.is_namath.sqrt
Imported modules
viz/premium

Discussion

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