Conditional operators

class IfElse

class IfElse

This operator uses a condition, which can be a fixed condition, an expression or a user-defined function, to determine which operators to be applied when this operator is applied. A list of if-operators will be applied when the condition is True. Otherwise a list of else-operators will be applied.

IfElse(cond, ifOps=[], elseOps=[], output=">", begin=0, end=-1, step=1, at=[], reps=ALL_AVAIL, subPops=ALL_AVAIL, infoFields=[])

Create a conditional operator that will apply operators ifOps if condition cond is met and elseOps otherwise. If a Python expression (a string) is given to parameter cond, the expression will be evalulated in each population’s local namespace when this operator is applied. When a Python function is specified, it accepts parameter pop when it is applied to a population, and one or more parameters pop, off, dad or mom when it is applied during mating. The return value of this function should be True or False. Otherwise, parameter cond will be treated as a fixed condition (converted to True or False) upon which one set of operators is always applied. The applicability of ifOps and elseOps are controlled by parameters begin, end, step, at and rep of both the IfElse operator and individual operators but ifOps and elseOps opeartors does not support negative indexes for replicate and generation numbers.

class TerminateIf

class TerminateIf

This operator evaluates an expression in a population’s local namespace and terminate the evolution of this population, or the whole simulator, if the return value of this expression is True. Termination caused by an operator will stop the execution of all operators after it. The generation at which the population is terminated will be counted in the evolved generations (return value from Simulator::evolve) if termination happens after mating.

TerminateIf(condition="", stopAll=False, message="", output="", begin=0, end=-1, step=1, at=[], reps=ALL_AVAIL, subPops=ALL_AVAIL, infoFields=[])

Create a terminator with an expression condition, which will be evalulated in a population’s local namespace when the operator is applied to this population. If the return value of condition is True, the evolution of the population will be terminated. If stopAll is set to True, the evolution of all replicates of the simulator will be terminated. If this operator is allowed to write to an output (default to “”), the generation number, proceeded with an optional message.

class RevertIf

class RevertIf

This operator replaces the current evolving population by a population loaded from a specified filename if certain condition is met. It is mostly used to return to a previously saved state if the simulation process fails to met a condition (e.g. a disease allele is lost).

RevertIf(cond, fromPop="", ops=[], output="", begin=0, end=-1, step=1, at=[], reps=ALL_AVAIL, subPops=ALL_AVAIL, infoFields=[])

Replaces the current evolving population by a population loaded from fromPop, which should be a file saved by function Population.save() or operator SavePopulation. If a Python expression (a string) is given to parameter cond, the expression will be evalulated in each population’s local namespace when this operator is applied. When a Python function with optional parameter pop is specified, it should accept the current population (to parameter pop) and converts and return True or False. Otherwise, parameter cond will be treated as a fixed condition (converted to True or False) upon which the population is reverted. After the population is reverted, an optional list of operators ops could be applied to the population.

class DiscardIf

class DiscardIf

This operator discards individuals according to either an expression that evaluates according to individual information field, or a Python function that accepts individual and its information fields.

DiscardIf(cond, exposeInd="", output="", begin=0, end=-1, step=1, at=[], reps=ALL_AVAIL, subPops=ALL_AVAIL, infoFields=[])

Create an operator that discard individuals according to an expression or the return value of a Python function (parameter cond). This operator can be applied to a population before or after mating, or to offspring during mating. If an expression is passed to cond, it will be evalulated with each individual’s information fields (see operator InfoEval for details). If exposeInd is non-empty, individuals will be available for evaluation in the expression as an variable with name spacied by exposeInd. If the expression is evaluated to be True, individuals (if applied before or after mating) or offspring (if applied during mating) will be removed or discard. If a function is passed to cond, it should accept paramters ind and pop or names of information fields when it is applied to a population (pre or post mating), or parameters off, dad, mom, pop (parental population), or names of information fields if the operator is applied during mating. Individuals will be discarded if this function returns True. A constant expression (e.g. True) is also acceptable). Because this operator supports parameter subPops, only individuals belonging to specified (virtual) subpopulations will be screened.