Constraints

class sweetpea.Constraint

Abstract class representing a constraint.

class sweetpea.Exclude(level)

Constrains an experiment to disallow the specified level.

An Exclude constraint can affect the number of trials that are included in a sequence. See CrossBlock for more information.

Parameters:

level (Union[Level, Tuple[Factor, Any], Tuple[Factor, Level]]) – either a level, a tuple containing a factor and the name of one of its levels, or a tuple containing a factor and one of its levels

Return type:

Constraint

class sweetpea.Pin(index, level)

Constrains an experiment to require the specified level at the specified trial index. A negative trial index refers to a trial releative to the end of a sequence; for example, -1 refers to the last trial. If index is not in range for trials in an experiment, then the experiment will have no satisfying trial sequences.

Parameters:

  • index (int) – a trial index, counting forward from 0 or backward from -1

  • level (Union[Level, Tuple[Factor, Any], Tuple[Factor, Level]]) – either a level, a tuple containing a factor and the name of one of its levels, or a tuple containing a factor and one of its levels

Return type:

Constraint

class sweetpea.MinimumTrials(k)

Constrains an experiment to set the specified number of minimum trials. See CrossBlock and Repeat for more information.

Parameters:

k (int) – minimum number of trials

class sweetpea.AtMostKInARow(k, level)

Constrains an experiment to allow at most k consecutive trials with the level identified by level.

Parameters:

  • k (int) – the maximum number of consecutive repetitions to allow

  • level (Union[Level, Tuple[Factor, Any], Tuple[Factor, Level], Factor]) – either a level, a tuple containing a factor and the name of one of its levels, a tuple containing a factor and one of its levels, or just a factor; the last case is a shorthand for a separate constraint for each of the factor’s levels

Return type:

Constraint

class sweetpea.AtLeastKInARow(k, level)

Constrains an experiment so that when the level identified by level appears in a trial, it also appears in at least k-1 adjacent trials.

Parameters:
Return type:

Constraint

class sweetpea.ExactlyKInARow(k, level)

Constrains an experiment so that when the level identified by level appears in a trial, it also appears in exactly k-1 adjacent trials.

Parameters:
Return type:

Constraint

class sweetpea.ExactlyK(k, level)

Constrains an experiment so that the level identified by level appears in exactly k trials. If this constraint is not consistent with requirements for crossing, the experiment will have no satisfying trial sequences.

Parameters:
Return type:

Constraint