go(de): make Population more ephemeral

algo/de/jDE.go

@@ -6,6 +6,7 @@
 import (
 	"log"
 	"os"
+	"time"
 
 	"git.dotya.ml/wanderer/math-optim/bench"
 	"git.dotya.ml/wanderer/math-optim/stats"
@@ -36,8 +37,6 @@ type JDE struct {
 	AdptScheme int
 	// NP is the initial population size.
 	NP int
-	// Population is a pointer to population
-	Population *Population
 	// BenchName is a name of the problem to optimise.
 	BenchName string
 	// ch is a channel for writing back computed results.
@@ -123,12 +122,6 @@ func (j *JDE) Init(generations, benchMinIters, mutStrategy, adptScheme, np int,
 	j.fVect = fV
 	j.crVect = crV
 
-	pop := newPopulation(bench, j.NP)
-
-	pop.Init()
-
-	j.Population = pop
-
 	j.initialised = true
 }
 
@@ -158,14 +151,22 @@ func (j *JDE) Run() {
 	for _, dim := range j.Dimensions {
 		maxFES := bench.GetGAMaxFES(dim)
 
-		j.evolve(maxFES)
+		// create a population with known params.
+		pop := newPopulation(j.BenchName, j.NP, dim)
+
+		// set population seed.
+		pop.Seed = uint64(time.Now().UnixNano())
+		// initialise the population.
+		pop.Init()
+
+		j.evolve(maxFES, pop)
 	}
 }
 
 // evolve evolves a population by running the jDE (self-adapting Differential
 // Evolution) algorithm on the passed population until termination conditions
 // are met.
-func (j *JDE) evolve(maxFES int) {}
+func (j *JDE) evolve(maxFES int, pop *Population) {}
 
 // NewjDE returns a pointer to a new, uninitialised jDE instance.
 func NewjDE() *JDE {

algo/de/population.go

@@ -38,6 +38,8 @@ type Population struct {
 	Population []PopulationIndividual
 	// Problem is the current benchmarking function this population is attempting to optimise.
 	Problem string
+	// Dimen is the dimensionality of the problem being optimised.
+	Dimen int
 	// Seed is the value used to (re)init population.
 	Seed uint64
 }
@@ -63,11 +65,13 @@ func (p *Population) Clear()         {}
 func (p *Population) MeanVelocity() float64 { return 0.0 }
 
 // newPopulation returns a pointer to a new, uninitialised population.
-func newPopulation(benchProblem string, np int) *Population {
+func newPopulation(benchProblem string, np, dimen int) *Population {
 	p := &Population{}
 
 	p.Problem = benchProblem
 
+	p.Dimen = dimen
+
 	// pre-alloc.
 	p.Population = make([]PopulationIndividual, 0, np)