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Uniform.scala
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Uniform.scala
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/*
* Copyright 2021 Arman Bilge
*
* 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 schrodinger.kernel
import cats.Functor
import cats.syntax.all.*
import schrodinger.math.LogDouble
trait Uniform[F[_], A]:
def uniform01: F[A]
def uniform10: F[A]
def uniform(include: A, exclude: A): F[A]
object Uniform:
inline def apply[F[_], A](include: A, exclude: A)(using u: Uniform[F, A]): F[A] =
u.uniform(include, exclude)
inline def standard[F[_], A](using u: Uniform[F, A]): F[A] = u.uniform01
given [F[_]: Functor: Random]: Uniform[F, Double] with
def uniform01 = Random.long.map(x => (x >>> 11) * 1.1102230246251565e-16)
def uniform10 = Random.long.map(x => ((x >>> 11) + 1) * 1.1102230246251565e-16)
def uniform(include: Double, exclude: Double) =
if exclude >= include then
val delta = exclude - include
uniform01.map(_ * delta + include)
else
val delta = include - exclude
uniform10.map(_ * delta + exclude)
given [F[_]: Functor](using double: Uniform[F, Double]): Uniform[F, LogDouble] with
def uniform01 = double.uniform01.map(LogDouble(_))
def uniform10 = double.uniform10.map(LogDouble(_))
def uniform(include: LogDouble, exclude: LogDouble) =
if exclude >= include then
val delta = exclude - include
uniform01.map(_ * delta + include)
else
val delta = include - exclude
uniform10.map(_ * delta + exclude)