scalismo.sampling.proposals.CombinedProposal.scala Maven / Gradle / Ivy
/*
* Copyright 2016 University of Basel, Graphics and Vision Research Group
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package scalismo.sampling.proposals
import scalismo.sampling.{ProposalGenerator, TransitionProbability}
/**
* Container for multiple ProposalGenerators stacked together, applied one after the other
*/
class CombinedProposal[A](val proposals: IndexedSeq[ProposalGenerator[A] with TransitionProbability[A]])
extends ProposalGenerator[A]
with TransitionProbability[A] {
override def propose(current: A): A = {
proposals.foldLeft(current) { (z: A, g: ProposalGenerator[A]) =>
g.propose(z)
}
}
/** transition from to */
override def logTransitionProbability(from: A, to: A): Double = {
proposals.foldLeft(0.0) { (z, g) =>
z + g.logTransitionProbability(from, to)
}
}
override def toString = {
val s = new StringBuilder("CombinedProposal(")
val firstNames = proposals.iterator.slice(0, 2).map(_.toString).mkString(",")
s.append(firstNames)
if (proposals.length > 2)
s.append(",...")
s.append(")")
s.toString()
}
}
object CombinedProposal {
def apply[A](proposals: IndexedSeq[(ProposalGenerator[A] with TransitionProbability[A])]) =
new CombinedProposal[A](proposals)
}