breeze.linalg.support.CanCollapseAxis.scala Maven / Gradle / Ivy
package breeze.linalg.support
/*
Copyright 2012 David Hall
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.
*/
/**
*
* This trait is for multi-dimensional tensors that can logically have one of their
* dimensions "collapsed", e.g. summing out all columns of a matrix to give a column
* vector.
*
* @author dlwh
* @tparam From the tensor being collapsed
* @tparam Axis which axis is being collapsed. Usually a subtype of [[breeze.linalg.Axis.Value]]
* @tparam ColType the type of the "column" (or row or...) being collapsed.
* @tparam R What the column is being collapsed to.
* @tparam TR result tensor type
*/
trait CanCollapseAxis[From, Axis, ColType, R, TR] {
def apply(from: From, axis: Axis)(f: ColType=>R):TR
}
object CanCollapseAxis {
/** Sometimes Scala can't deal with the R/TR part if it's being chained. This
* delays some of the inference of [[breeze.linalg.support.CanCollapseAxis]]'s parameters
* until they can be further resolved. (See [[breeze.generic.UFunc.collapseUred]] for an example.) */
class HandHold[From, Axis, ColType]
}