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com.barrybecker4.simulation.reactiondiffusion.algorithm.GrayScottAlgorithm.scala Maven / Gradle / Ivy
/** Copyright by Barry G. Becker, 2000-2017. Licensed under MIT License: http://www.opensource.org/licenses/MIT */
package com.barrybecker4.simulation.reactiondiffusion.algorithm
import com.barrybecker4.common.concurrency.ThreadUtil
/**
* This is the core of the Gray-Scott reaction diffusion simulation implementation.
* Based on an work by Joakim Linde and modified by Barry Becker.
*/
object GrayScottAlgorithm {
/** We could add scrollbars to scale these */
private val DU: Double = 2.0e-5
private val DV: Double = 1.0e-5
}
final class GrayScottAlgorithm private[algorithm](model: GrayScottModel) {
private var duDivh2: Double = _
private var dvDivh2: Double = _
def computeNextTimeStep(minX: Int, maxX: Int, dt: Double) {
val u = model.tmpU
val v = model.tmpV
val height = model.getHeight
//println(s"minX=$minX maxX=$maxX ht=$height")
for (x <- minX to maxX)
for (y <- 1 until height - 1) {
val vval = v(x)(y)
val uv2 = u(x)(y) * vval * vval
//if (uv2 > 10.0) println("error uv2 = " + uv2 + " u = " + u(x)(y) + " v=" + vval)
model.u(x)(y) = calcNewCenter(u, x, y, duDivh2, useF = true, uv2, dt)
model.v(x)(y) = calcNewCenter(v, x, y, dvDivh2, useF = false, uv2, dt)
}
}
def computeNewEdgeValues(dt: Double) {
val width = model.getWidth
val height = model.getHeight
for (x <- 0 until width) { // top and bottom edges
calcEdge(x, 0, dt)
calcEdge(x, height - 1, dt)
}
for (y <- 0 until height) { // left and right edges
calcEdge(0, y, dt)
calcEdge(width - 1, y, dt)
}
}
def setH(h: Double) {
val h2 = h * h
duDivh2 = GrayScottAlgorithm.DU / h2
dvDivh2 = GrayScottAlgorithm.DV / h2
}
/** Calculate new values on an edge. */
private def calcEdge(x: Int, y: Int, dt: Double) = {
val tmpV = model.tmpV(x)(y)
val uv2 = model.tmpU(x)(y) * tmpV * tmpV
model.u(x)(y) = calcNewEdge(model.tmpU, x, y, duDivh2, useF = true, uv2, dt)
model.v(x)(y) = calcNewEdge(model.tmpV, x, y, dvDivh2, useF = false, uv2, dt)
}
/** @return new value for a center point. */
private def calcNewCenter(tmp: Array[Array[Double]], x: Int, y: Int, dDivh2: Double, useF: Boolean, uv2: Double,
dt: Double): Double = {
val sum = model.getNeighborSum(tmp, x, y) - 4.0 * tmp(x)(y)
calcNewAux(tmp(x)(y), sum, dDivh2, useF, uv2, dt)
}
/** @return new value for an edge point. */
private def calcNewEdge(tmp: Array[Array[Double]], x: Int, y: Int,
dDivh2: Double, useF: Boolean, uv2: Double, dt: Double): Double = {
val sum = model.getEdgeNeighborSum(tmp, x, y) - 4.0 * tmp(x)(y)
calcNewAux(tmp(x)(y), sum, dDivh2, useF, uv2, dt)
}
private def calcNewAux(txy: Double, sum: Double, dDivh2: Double, useF: Boolean, uv2: Double, dt: Double): Double = {
val c = if (useF) model.getF * (1.0 - txy) - uv2
else uv2 - model.getK * txy
txy + dt * (dDivh2 * sum + c)
}
}
