vignettes/quickstart.md

In florisc/pbar: Simple to Entirely Customizable Progress Bar with Low Memory Consumption and CPU Usage

title: "Quick start with pbar: Progress bar" author: "Floris CHABRUN" date: "03/01/2018" output: rmarkdown::html_vignette vignette: > %\VignetteIndexEntry{Vignette Title} %\VignetteEngine{knitr::rmarkdown} %\VignetteEncoding{UTF-8}

Quick start with pbar: Progress bar

First steps into displaying your first progress bar

Create the progress bar object

Creating and displaying a progress bar with pbar is extremely simple.

First, create a progress bar object with the pbar new() function.

pb = pbar$new()

If you now how many iterations will occur, you can pass this value as the max parameter :

n = 100000
pb = pbar$new(n)

By default, the progress bar starts with current index set to 0. You can change this value by modifying the ini parameter :

pb = pbar$new(max = n, ini = 5000)

Full list of available parameters can be found by typing help(pbInit) in the R console.

Run the progress bar

Then, while in-loop, just call the pbar update() method to provoke automatic values update of the pbar object, as well as console output refresh :

for(i in 1:n) {
  Sys.sleep(0.001)
  pb$update()
}

If the update function is not called at every iteration of the loop, you can specify a delta index as a parameter of the update() function :

The use of this feature is discouraged. For performance improvment, modifying outputpace and mindelay parameters should be done instead (see Performance optimization).

for(i in 1:n) {
  Sys.sleep(0.001)
  if (i %% 2==0)
    pb$update(2)
}

Progress bar customization

The progress bar created with pbar is entirely customizable. Here are some possible formatting options for the console output :

# Change the classic |#####/    | to a |=====/----| style :
pb = pbar$new(n, cursors = c('=','-'))

# Change the size of the progress bar, here on 20 characters : |##########/         |
pb = pbar$new(n, barlength = 20)

# Remove spinning cursor in middle of progress bar 
pb = pbar$new(n, spinningcursor = FALSE)

The time can be formatted in two ways : short format or exact format. The examples below show how the time will be output according to the chosen format :

• Time in seconds : 32 165 3601 5421.15 452632.456
• Short format : 32s 3m 1h 2h 5d
• Exact format : 00:00:32.00s 00:02:45.00s 01:01:00.00s 01:30:21.15s 125:43:52.46s

Below are some examples to change the time format in the console output :ting options for the console output :

# Give a rapid straight-forward look
pb = pbar$new(n, format = 'Progress: :bar:percent Elapsed: :elapsed ETA: :eta/:tet')

# Change the format to show exact informations :
pb = pbar$new(n, format = ':current/:total :bar:percent Elapsed: :elapsedexact ETA: :etaexact Total: :tetexact')

# See short time format for elapsed and eta, but exact total estimated time :
pb = pbar$new(n, format = 'Progress: :bar:percent Elapsed: :elapsed ETA: :eta Total: :tetexact')

Performance optimization

Progress bar performance depends widely on two initialization parameters :

outputpace determines the minimum iterations between two console updates. By default, when this value is omitted, it is automatically set to 0.01% of the total number of iterations.

mindelay determines the minimal delay (in seconds) between two console updates.

Default values when creating a progress bar instance are chosen to optimize performance and CPU-usage. Nonetheless, you can modify those parameters, for example to force output at every loop iteration :

# Refresh console at every iteration without minimal delay between two updates
pb = pbar$new(outputpace = 1, mindelay = 0)

florisc/pbar documentation built on May 25, 2019, 5:22 p.m.