Move experiment to package, apply values to a world

_examples/experiment/main.go

@@ -12,6 +12,7 @@ import (
 	amodel "github.com/mlange-42/arche-model/model"
 	"github.com/mlange-42/arche-model/reporter"
 	"github.com/mlange-42/arche-model/system"
+	"github.com/mlange-42/beecs/experiment"
 	"github.com/mlange-42/beecs/model"
 	"github.com/mlange-42/beecs/obs"
 	"github.com/mlange-42/beecs/params"
@@ -20,7 +21,7 @@ import (
 
 func main() {
 	// Define parameter variations.
-	vars := []params.ParameterVariation{
+	vars := []experiment.ParameterVariation{
 		{
 			Parameter: "params.InitialPopulation.Count",
 			Type:      "sequence-values",
@@ -34,12 +35,12 @@ func main() {
 	}
 
 	// Create an experiment.
-	experiment, err := params.NewExperiment(vars, rand.New(nil))
+	exp, err := experiment.New(vars, rand.New(nil))
 	if err != nil {
 		log.Fatal(err)
 	}
 	// Get the number of parameter sets in the experiment.
-	sets := experiment.ParameterSets()
+	sets := exp.ParameterSets()
 
 	// Create an empty model.
 	m := amodel.New()
@@ -48,26 +49,22 @@ func main() {
 
 	for i := 0; i < sets; i++ {
 		// Get and print the parameter values for the current run.
-		values := experiment.Values(i)
+		values := exp.Values(i)
 		fmt.Printf("Running set %v\n", values)
 
 		// Initialize and run the model with the given parameters.
-		run(m, values, i)
+		run(m, &exp, i)
 	}
 }
 
-func run(m *amodel.Model, values map[string]any, idx int) {
+func run(m *amodel.Model, exp *experiment.Experiment, idx int) {
 	// Get the default parameters.
 	p := params.Default()
 	// Create a model with the default sub-models.
 	m = model.Default(&p, m)
 
 	// Set/overwrite parameters from the experiment.
-	for par, value := range values {
-		if err := model.SetParameter(&m.World, par, value); err != nil {
-			log.Fatal(err)
-		}
-	}
+	exp.ApplyValues(idx, &m.World)
 
 	// Add a system ("sub-model") to terminate after 365 ticks.
 	m.AddSystem(&system.FixedTermination{Steps: 365})

params/experiment.go → experiment/experiment.go

@@ -1,16 +1,19 @@
-package params
+package experiment
 
-import "golang.org/x/exp/rand"
+import (
+	"github.com/mlange-42/arche/ecs"
+	"github.com/mlange-42/beecs/model"
+	"golang.org/x/exp/rand"
+)
 
 type Experiment struct {
-	values        map[string]any
 	rng           *rand.Rand
 	parameters    []string
 	functions     []ParameterFunction
 	parameterSets int
 }
 
-func NewExperiment(vars []ParameterVariation, rng *rand.Rand) (Experiment, error) {
+func New(vars []ParameterVariation, rng *rand.Rand) (Experiment, error) {
 	pars := []string{}
 	f := []ParameterFunction{}
 
@@ -30,7 +33,6 @@ func NewExperiment(vars []ParameterVariation, rng *rand.Rand) (Experiment, error
 		functions:     f,
 		parameterSets: stride,
 		rng:           rng,
-		values:        map[string]any{},
 	}, nil
 }
 
@@ -42,10 +44,25 @@ func (e *Experiment) Parameters() []string {
 	return e.parameters
 }
 
-func (e Experiment) Values(idx int) map[string]any {
+func (e *Experiment) Seed(seed uint64) {
+	e.rng.Seed(seed)
+}
+
+func (e *Experiment) Values(idx int) map[string]any {
+	values := map[string]any{}
 	for i, par := range e.parameters {
 		fn := e.functions[i]
-		e.values[par] = fn.Next(idx, e.rng)
+		values[par] = fn.Next(idx, e.rng)
+	}
+	return values
+}
+
+func (e *Experiment) ApplyValues(idx int, world *ecs.World) error {
+	values := e.Values(idx)
+	for par, value := range values {
+		if err := model.SetParameter(world, par, value); err != nil {
+			return err
+		}
 	}
-	return e.values
+	return nil
 }

params/experiment_test.go → experiment/experiment_test.go

@@ -1,4 +1,4 @@
-package params
+package experiment
 
 import (
 	"testing"
@@ -23,7 +23,7 @@ func TestExperiment(t *testing.T) {
 		},
 	}
 
-	e, err := NewExperiment(vars, rng)
+	e, err := New(vars, rng)
 
 	assert.Nil(t, err)
 

params/variation.go → experiment/variation.go

@@ -1,4 +1,4 @@
-package params
+package experiment
 
 import (
 	"fmt"