LibraryStopwatch

// This source code is subject to the terms of the Mozilla Public License 2.0 at https://mozilla.org/MPL/2.0/
// © goodgains


//@version=5











// @keywords: stopwatch, library-stopwatch, script-execution-time, execution-timing, ms-per-bar, total-execution-time, elapsed-time, average-time-per-bar, bars-timed, bars-not-timed, bars-analyzed, performance-benchmark, script-benchmark, runtime-measurement, performance-profiling, loop-iterations, execution-stats, timing-stats, script-performance, code-profiling

// @description Provides functions to time the execution of a script.
library("LibraryStopwatch")

loopCount = input.int(100000, "Loop iterations per bar", minval = 0, step = 10000)

// @function Times the execution of a script.
// @returns A tuple of four values: [timePerBarInMs, totalTimeInMs, barsTimed, barsNotTimed]
export stopwatchStats() =>
    // Get time at first bar.
    var int timeBegin = timenow
    // Get ms elapsed since first bar.
    var int timeElapsed = 0
    if not barstate.islast
        timeElapsed := timenow - timeBegin
    // Calculate avg/bar only when time changes.
    var float timePerBarInMs = 0.
    // Total bars timed before last change in "timenow".
    var int barsTimed = 0
    // ————— Bars elapsed since last change in "timenow".
    var int barsNotTimed = 0
    if ta.change(timeElapsed)
        barsTimed := bar_index + 1
        timePerBarInMs  := timeElapsed / barsTimed
    // ————— In between time changes, estimate elapsed time using avg time per bar.
    if not barstate.islast
        // Bars elapsed since last change of time.
        barsNotTimed := bar_index  + 1 - barsTimed
    // ————— Add (bars since "timenow" change * avg bar time) to time elapsed since last "timenow" change to get better estimate of total time elapsed.
    float totalTimeInMs = timeElapsed + (barsNotTimed * timePerBarInMs)
    [timePerBarInMs, totalTimeInMs, barsTimed, barsNotTimed]

// @function    Times the execution of a script.
// @returns     A single value: The time elapsed since the beginning of the script, in ms.
export stopwatch() =>
    // Get time at first bar.
    var int timeBegin = timenow
    // Get ms elapsed since first bar.
    var int timeElapsed = 0
    if not barstate.islast
        timeElapsed := timenow - timeBegin
    // Calculate avg/bar only when time changes.
    var float timePerBarInMs = 0.
    // Total bars timed before last change in "timenow".
    var int barsTimed = 0
    // ————— Bars elapsed since last change in "timenow".
    var int barsNotTimed = 0
    if ta.change(timeElapsed)
        barsTimed := bar_index + 1
        timePerBarInMs  := timeElapsed / barsTimed
    // ————— In between time changes, estimate elapsed time using avg time per bar.
    if not barstate.islast
        // Bars elapsed since last change of time.
        barsNotTimed := bar_index  + 1 - barsTimed
    // ————— Add (bars since "timenow" change * avg bar time) to time elapsed since last "timenow" change to get better estimate of total time elapsed.
    float totalTimeInMs = timeElapsed + (barsNotTimed * timePerBarInMs)

// Examples of calls to both functions.
[timePerBarInMs, totalTimeInMs, barsTimed, barsNotTimed] = stopwatchStats()
msElapsed = stopwatch()

// ————— Script code to time.
var a = 0.
for i = 0 to loopCount
    a := a + i + close + math.pow(hl2, 1 / i) + math.avg(close, open) + math.cos(hlc3)

// —————————— Display results
// ————— Print table at the end of chart.
if barstate.islast
    var table t = table.new(position.middle_right, 1, 1)
    var txt = str.tostring(timePerBarInMs, "ms/bar: #.######\n") +
              str.tostring(totalTimeInMs, "Total time (ms): #,###.######\n") + 
              str.tostring(barsTimed + barsNotTimed, "Bars analyzed: #")
    table.cell(t, 0, 0, txt, bgcolor = color.yellow, text_halign = text.align_right)

// ————— Plot elapsed time.
plot(totalTimeInMs,  "totalTimeInMs", color.gray)
plot(msElapsed,      "msElapsed",     color.new(color.gray, 70), 6)

// ————— Print Data Window values.
plotchar(timePerBarInMs,    "Avg time / bar (ms)",  "", location.top)
plotchar(totalTimeInMs,     "Execution time (ms)",  "", location.top)
plotchar(barsTimed,         "Bars timed",           "", location.top)
plotchar(barsNotTimed,      "Bars not timed",       "", location.top)