Random Layers

Random Layer Example

Random Layer Example

In a random layer, ROCK MAKER dispenses each well and its drops using ingredients randomly selected from among those you have chosen to include in the experiment. Concentrations and pHs of the ingredients are also randomly selected from sets of values that you have defined.

How Ingredients are Selected

When selecting ingredients to dispense in a well of a random layer, ROCK MAKER first decides which ingredient groups will be used in the well by looking at the probability you have assigned to each group in the Generation List.

Groups with higher probabilities have a better chance of being used in the well. In each selected group, ROCK MAKER chooses one ingredient to dispense in the well based on the weight value you have assigned to the ingredient on the Group Ingredients table.

How Concentrations and pHs are Selected

When designing a random layer, you must define minimum and maximum values for the following attributes:

  • Concentration of each ingredient

  • pH of each buffer ingredient

ROCK MAKER uses these values, along with the number of grid steps you have specified on the Random Layer Options tab, to come up with sets of values from which it will randomly select concentrations and pH levels in the random layer. The number of values is defined by the number of steps you entered.

Each set will be generated by selecting numbers between the minimum and maximum values at a fixed increment, determined by the number of grid steps. This results in a set of numbers for each attribute, the number of values in each set being equal to the number of grid steps.

The following table illustrates this by showing the sets of values generated using the given minimum and maximum values and five grid steps. For each attribute listed in the left column, one value will be chosen from the set in the right column for each well.




A value is randomly chosen from:





0.2, 0.4, 0.6, 0.8, 1.0




2.5, 3.5, 4.5, 5.5, 6.5

How ROCK MAKER Varies Ingredients in a Random Layer

For each well generated in the random layer, ROCK MAKER:

  1. Determines which ingredient groups will be used in dispensing the well by looking at the probability you have assigned to each group on the Generation List.

  2. Randomly chooses one ingredient from each ingredient group selected for use in the well based on the ingredients’ probabilities.

  3. Dispenses the selected ingredients into the well.

  4. Dispenses some of the well solution into the well’s drops.

  5. Repeats steps 1 – 4 for each well to be dispensed in the experiment.

Exclude List

The Exclude List allows you to define pairs of ingredients that should never be mixed in the same experiment well. When selecting ingredients randomly, ROCK MAKER will make sure that none of the combinations on the Exclude List occurs.

Exclude List

Exclude List

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