Overview

The Library List shows all of your populations. It is organized into two sections, the Gene Pool section and the User Library section. The Gene Pool section lists populations that are gene pools, and the User Population section lists your populations that are evolving.

Viewing Populations

When you tap on one of the populations in the list, the population's details will be presented in the Population Detail view, and it's turtles will be presented in the Population Preview view. If you want to open a population in the Population View to work with it, you have two options. You can tap on the detail disclosure button next to the population's name in the Library List, or you can tap on the Show Population button at the bottom of the Population Detail view. Either of these taps will present the Population View. Adding new populations to your library is discussed in detail further down on this page.

Overview

The Population View will display details about the population that you select in the Library List view. These details include the population's name, size, and author information. At the top of the view, the population name is presented in a special area that includes an Edit button (which is not a tradition button, but just the word 'Edit'). If you click on the Edit button, a popover will be displayed allowing you to change the name and comment for the population.

Overview

The Preview View will display details about the turtles in the population that you select in the Library List view. The turtles are displayed in a horizontally scrolling grid. Each turtle is shown in a tile that includes an image of the turtle's drawing, as well as the turtle's Unique Identifier, and information about the turtle's author.

Adding Populations

You can create new populations or import existing populations using the Add button at the top of the Library List. When you tap on this button, you will be presented with an action sheet providing options to create a new population or gene pool, or to import a population or gene pool from iTunes.

When you tap on the action to create a new gene pool, you will be presented with a simple popup allowing you to provide a name for the new gene pool. Enter the name, and the gene pool will be created and added to your Library List. When you tap on the action to create a new population, you will be presented with a more complicated popup to name and configure the new population. The popup is more complicated because populations have many more attributes than gene pools. While the popup is more complicated, you do not need to be concerned with the details when you first start using Evolved Art. The various configuration parameters for a new population will become of more interest to you once you are more experienced with evolving populations and wish to have more control over their evolution.

Importing populations from iTunes will present you with a popup listing the files that are available in iTunes. These will be files that you exported from Evolved Art, or files that you received from other Evolved Art users and copied into iTunes. These files will always be population definition files, whose names end with the suffix ".population". When you select a population from the list, the population definition will be read, and the population will be presented in the Import Population view. Here you can preview the population to decide if you really wish to import it. The Import Population view provides to buttons that allow you to import the population into a gene pool, or into a population that can evolve.

Finally, populations can be added to your library when population definitions are opened in other iPad apps. For example, if another user emails a population definition to you, you can request the mail app to open the definition file in Evolved Art (for example by tapping and holding on the attachment's icon when viewing the email). When this is done, the Evolved Art app will be opened and a preview of the population will be presented to you, giving you the option to import the population into the User Population or Gene Pool section of your library.

Please note that importing populations from iTunes, as well as opening populations from other iPad apps can only be done from the Library View. If you are currently in another view, an alert will be presented to you informing you of this limitation, and you will need to return to the Library View and import or open again.

New Population PopUp

The first page of the New Population popup is relatively simple. You provide a name for your population, as well as a size. The name entry field is a traditional text entry field, so just click in it and the keyboard will appear to allow you to type. The size is determined by selecting one of the available sizes in the Number Of Turtles segment bar below the name field.

Below the Number Of Turtles control, you will see two sliders: one that controls the Depth, and one that controls Children. The purpose of these settings involves an understanding of turtle programs and their representation as expression trees. The depth setting determines the maximum height of the generated expression trees. The greater the depth setting, the deeper the expression trees can be. The children setting determines the maximum number of children that any function node in the expression tree can have. You may think of this setting as a limit on the width of the expression tree. The important thing to understand is that these two settings control the overall size of the programs that are randomly generated for your turtles. The larger these two settings, the larger and more complex the turtle programs will be. More importantly, the larger these two settings are, the more memory the population will require. If these settings are both set to their maximum values, you will see a warning about memory requirements. It is possible that Evolved Art will exhaust the memory on your iPad when attempting to work with the population and be forced to shutdown.

Finally, you tap the Create New Population button to create the new population and add it to your library. The popup will be dismissed, and you will see the new population in the Library List view.

Advanced Parameters

If you click on the Advanced button in the toolbar at the top of the New Population popup, the popup will present the Advanced Parameters view. When you first start to use Evolved Art, you should simply accept the default values. However, as you become more advanced, and better understand the mechanics of evolution in your populations, you may wish to modify these parameters to better control the evolution of your population.

The left side of the view provides slider controls for Evolution Probabilities, while the right side of the view provides slider controls for Fitness Multipliers. These values are described in more details below.

Evolution Probabilities

The internals of Evolved Art's evolution involves many events that are determined by chance. You can think of this as flipping a coin - heads the event goes one way, tails it goes the other way. These probability settings determine the odds of getting a head or a tail. If you select 80%, then the coin toss will generally produce 80 heads for each 100 flips, and 20 tails for each 100 flips.

Probability Of Crossover

This probability applies to the probability that when two turtles reproduce with each other, their DNA will actually cross over and recombine. When the coin is tossed, heads will cause crossover to occur, and tails will leave the two turtles with their original DNA. In this case, the DNA in question is the turtles' programs. Clearly, you will want this value to be high, unless you wish for the population to evolve at a very slow pace.

Probability Of Color Change

This probability applies to the likelihood that when the turtle programs are first generated randomly, or when mutation occurs, that the program instruction that is created will involve changing the turtle's drawing color. In other words, the higher this probability, the more likely the turtle's drawing will change colors.

Probability Of Function

This probability applies to the likelihood that when the turtle programs are first generated randomly, or when mutation occurs, that the program instruction that is created will be a function, as opposed to a terminal. Function and terminal are concepts in program languages and parsing. If they are unfamiliar to you, do not worry. Simply understand that the higher this probability, the more complex your turtle programs will be.

Probability Of Mutation

This probability applies to the likelihood that when a population is evolved into the next generation mutation will occur. The details of how Evolved Art implements mutation is discussed elsewhere. Just know that the higher this probability the more mutation will occur during evolution.

Fitness Multipliers

When Evolved Art evolves a population into the next generation, it does so by selecting turtles to reproduce and having those turtles produce offspring. The selection of the turtles that reproduce is based on their fitness. The more fit a turtle is, the more likely it is to be selected for reproduction. The fitness is determined by the properties listed below. These multipliers are used to increase or decrease the importance of each property. The higher the multiple, the more important the property.

Moving Forward

This property is in regards to how much the turtle moves forward. When you see a line drawn in the turtle's drawing, it is moving forward.

Turning

This property is in regards to how much the turtle turns. When you see the line in a turtle's drawing change direction left or right, it is turning.

Looping

This property is in regards to how much the turtle loops. A loop occurs when the turtle turns left or right by 360 degrees, or a complete turn around.

Coloring

This property is in regards to how often the turtle changes color while it is drawing.

Repeating

This property is in regards to how often the turtle's program repeats certain parts of the program. The turtle program language includes instructions that repeat sections of the program. When the program includes these repeat instructions, this property applies.

Repetition

This property is in regards to repeats in the turtle's program and the repetitions they create. A repeat instruction has a count. For example, repeat 5 times. Repetitions are in regards to the sum of the counts of the repeats that occur in the turtle's program.

Deleting A Population From Your Library

You can delete populations from your library using the standard iPad method for deleting items from a list. Simply swipe your finger from left to right over one of the populations listed in the library list. This will display a red delete button as shown in the image to the left. Tap the delete button and the population will be deleted from your library. Swipe your finger from left to right again (being careful not to touch the delete button), and the delete operation will be canceled.

WARNING: this operation cannot be undone! Therefore, you might want to consider exporting the population's definition file to iTunes, or emailing the population to yourself, before you delete the population. Just in case.