func newStrategy(target, reference quantity.Quantity, guide hybrid.Guide,
config *config.Solution) *strategy {
ni, no := target.Dimensions()
return &strategy{
Strategy: *hybrid.NewStrategy(ni, no, guide, config.MinLevel, config.MaxLevel,
config.AbsoluteError, config.RelativeError, config.ScoreError),
target: target,
reference: reference,
nmax: config.MaxEvaluations,
}
}
func generate(into, from quantity.Quantity, ns uint, seed int64) []float64 {
ni, _ := into.Dimensions()
nf, _ := from.Dimensions()
zi := make([]float64, ni*ns)
zf := support.Generate(nf, ns, seed)
for i := uint(0); i < ns; i++ {
copy(zi[i*ni:(i+1)*ni], into.Forward(from.Backward(zf[i*nf:(i+1)*nf])))
}
return zi
}
func function(config *config.Config) error {
if len(*sampleSeed) > 0 {
if number, err := strconv.ParseInt(*sampleSeed, 0, 64); err != nil {
return err
} else {
config.Assessment.Seed = number
}
}
if len(*sampleCount) > 0 {
if number, err := strconv.ParseUint(*sampleCount, 0, 64); err != nil {
return err
} else {
config.Assessment.Samples = uint(number)
}
}
if config.Assessment.Samples == 0 {
return errors.New("the number of samples should be positive")
}
approximate, err := database.Open(*approximateFile)
if err != nil {
return err
}
defer approximate.Close()
output, err := database.Create(*outputFile)
if err != nil {
return err
}
defer output.Close()
system, err := system.New(&config.System)
if err != nil {
return err
}
auncertainty, err := uncertainty.NewAleatory(system, &config.Uncertainty)
if err != nil {
return err
}
aquantity, err := quantity.New(system, auncertainty, &config.Quantity)
if err != nil {
return err
}
euncertainty, err := uncertainty.NewEpistemic(system, &config.Uncertainty)
if err != nil {
return err
}
equantity, err := quantity.New(system, euncertainty, &config.Quantity)
if err != nil {
return err
}
var target, proxy quantity.Quantity
if config.Solution.Aleatory {
target, proxy = aquantity, aquantity // noop
} else {
target, proxy = equantity, aquantity
}
ni, no := target.Dimensions()
ns := config.Assessment.Samples
surrogate := new(solution.Surrogate)
if err = approximate.Get("surrogate", surrogate); err != nil {
return err
}
solution, err := solution.New(ni, no, &config.Solution)
if err != nil {
return err
}
points := generate(target, proxy, ns, config.Assessment.Seed)
log.Printf("Evaluating the surrogate model at %d points...\n", ns)
log.Printf("%5s %15s\n", "Step", "Nodes")
nk := uint(len(surrogate.Active))
cumsum := append([]uint(nil), surrogate.Active...)
for i := uint(1); i < nk; i++ {
cumsum[i] += cumsum[i-1]
}
indices := choose.UniformUint(cumsum, maxSteps)
nk = uint(len(indices))
active := make([]uint, nk)
for i := uint(0); i < nk; i++ {
active[i] = cumsum[indices[i]]
}
values := make([]float64, 0, ns*no)
for i := uint(0); i < nk; i++ {
log.Printf("%5d %15d\n", i, active[i])
s := *surrogate
s.Nodes = active[i]
s.Indices = s.Indices[:active[i]*ni]
s.Surpluses = s.Surpluses[:active[i]*no]
if !solution.Validate(&s) {
panic("something went wrong")
}
values = append(values, solution.Evaluate(&s, points)...)
}
if err := output.Put("surrogate", *surrogate); err != nil {
return err
}
if err := output.Put("points", points, ni, ns); err != nil {
return err
}
if err := output.Put("values", values, no, ns, nk); err != nil {
return err
}
if err := output.Put("active", active); err != nil {
return err
}
return nil
}
func function(config *config.Config) error {
output, err := database.Create(*outputFile)
if err != nil {
return err
}
defer output.Close()
system, err := system.New(&config.System)
if err != nil {
return err
}
auncertainty, err := uncertainty.NewAleatory(system, &config.Uncertainty)
if err != nil {
return err
}
aquantity, err := quantity.New(system, auncertainty, &config.Quantity)
if err != nil {
return err
}
euncertainty, err := uncertainty.NewEpistemic(system, &config.Uncertainty)
if err != nil {
return err
}
equantity, err := quantity.New(system, euncertainty, &config.Quantity)
if err != nil {
return err
}
var target, reference quantity.Quantity
if config.Solution.Aleatory {
target, reference = aquantity, equantity
} else {
target, reference = equantity, aquantity
}
ni, no := target.Dimensions()
solution, err := solution.New(ni, no, &config.Solution)
if err != nil {
return err
}
log.Println("System", system)
log.Println("Quantity", target)
if config.Solution.Aleatory {
log.Println("Constructing an aleatory surrogate...")
} else {
log.Println("Constructing an epistemic surrogate...")
}
surrogate := solution.Compute(target, reference)
log.Println("Surrogate", surrogate)
if err := output.Put("surrogate", *surrogate); err != nil {
return err
}
return nil
}