Thermal Regimes

Brian S. Yandell

03 August 2026

This document details the routines in the ewing package for adjusting daily high/low temperatures and life stage transition splines, as well as the refactoring details for tempApp() and its Shinylive WebAssembly demo.

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1. Core Spline & Temperature Routines

Interactive spline adjustment functions in ewing:

Temperature-Time Spline Adjustment

• temp.design() in R/temp.design.R: Legacy interactive console routine using graphics::locator() to adjust daily high/low temperature knots.

General & Mean-Value Spline Adjustment

• spline.design() in R/spline.R: General prototype function for designing spline curves using the cursor, delegating to curve.plot().
• future.meanvalue() & spline.meanvalue() in R/future.meanvalue.R: Interactively design mean value curves for life stage transition events.
• five.plot() & five.show() in R/five.R: Interactive tools for studying 5-parameter relationships of time and mean value.

Shiny Applications & WebAssembly Demos

• fivePlotApp() & fiveShowApp(): Modern reactive Shiny apps for parameter sensitivity and target search.
• tempApp(): Interactive daily temperature spline and degree-day design explorer.

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2. Refactoring Rationale for tempApp

Legacy Graphics Locator vs. Reactive Shiny UI

• Legacy temp.design() relied on graphics::locator() in a modal loop. While functional in desktop R console sessions, locator() blocks event dispatchers in web environments.
• tempApp() replaces this with a reactive Shiny interface built on bslib::page_sidebar. Node moves are captured via input$temp_click and immediately updated in reactive state (shiny::reactiveValues).

Dual Spline (High & Low Temperature) Management

• In ewing, daily thermal fluctuation is specified by daily high and low cubic splines (High and Low elements of community$temp).
• tempApp() allows users to switch between editing High and Low temperature splines via radio buttons, maintaining separate node coordinate vectors.

Degree-Day Integration (activeTemp())

• Stage transition kinetics in the simulation depend on degree-days (DD). Any adjustment to high/low daily temperatures triggers activeTemp(community), which integrates degree-days using temp.repeat() and temp.spline().
• tempApp() displays side-by-side plots:
  • Left (plot_temp): Interactive daily high (red) and low (blue) temperature splines with click-to-move node editing.
  • Right (plot_degreeday): Real-time degree-day accumulation curve generated by temp.plot(community).

Monotonicity Boundaries

• Day knots ($X$) must remain strictly increasing ($x_1 < x_2 < \dots < x_n$) to allow valid cubic spline interpolation. Node moves on click are automatically constrained between neighboring knot boundaries ($x_{i-1} + 0.01 \le x_i \le x_{i+1} - 0.01$).

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3. Implementation Summary

Package Function (R/tempApp.R)

• Signature: tempApp(community = NULL, title = "Daily Temperature Design Explorer")
• Default Input: If community is NULL, automatically initializes mysim <- ewing::init.simulation(messages = FALSE).
• UI: bslib::page_sidebar layout featuring curve radio buttons, coordinate text inputs (x_coords, y_coords), minimum temperature input (min_temp), and side-by-side plots for temperature splines and degree-day accumulation.
• Server: Manages reactive state, bidirectional synchronization between plot clicks and sidebar inputs, monotonicity enforcement, and real-time activeTemp() degree-day recalculations.

Shinylive WebAssembly Demo (demos/tempApp.qmd)

• Quarto HTML document embedding {shinylive-r} code blocks (standalone: true, viewerHeight: 750).
• Embeds lightweight standalone temperature helper functions so the app runs self-contained in browser WebAssembly without requiring a server backend.

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4. Verification

1. R Documentation & Package Export: Executed devtools::document() and devtools::load_all('.'). Verified man/tempApp.Rd creation and NAMESPACE export.
2. Simulation Initialization Test: Verified default initialization with mysim <- init.simulation() and temperature spline extraction (getTemp(mysim, "High") & getTemp(mysim, "Low")).
3. Degree-Day Recalculation Test: Verified that calling activeTemp() updates DegreeDay and Hour splines without error and temp.plot() renders cleanly.