integrate quantity scale into support strategy and grid strategy

config/support.yaml

@@ -59,8 +59,12 @@ exchangeStrategies:
   support:
     symbol: LINKUSDT
     interval: 1m
-    minVolume: 200000
-    quantity: 2.0
+    minVolume: 1_000
+    scaleQuantity:
+      byVolume:
+        exp:
+          domain: [ 1_000, 200_000 ]
+          range: [ 0.5, 1.0 ]
     targets:
     - profitPercentage: 0.02
       quantityPercentage: 0.5

pkg/bbgo/scale.go

@@ -3,8 +3,24 @@ package bbgo
 import (
 	"fmt"
 	"math"
+
+	"github.com/pkg/errors"
 )
 
+type Scale interface {
+	Solve() error
+	Formula() string
+	FormulaOf(x float64) string
+	Call(x float64) (y float64)
+}
+
+func init() {
+	_ = Scale(&ExponentialScale{})
+	_ = Scale(&LogarithmicScale{})
+	_ = Scale(&LinearScale{})
+	_ = Scale(&QuadraticScale{})
+}
+
 // y := ab^x
 // shift xs[0] to 0 (x - h)
 // a = y1
@@ -14,7 +30,7 @@ import (
 // y2/y1 = b^(x2-h)
 //
 // also posted at https://play.golang.org/p/JlWlwZjoebE
-type ExpScale struct {
+type ExponentialScale struct {
 	Domain [2]float64 `json:"domain"`
 	Range  [2]float64 `json:"range"`
 
@@ -23,26 +39,26 @@ type ExpScale struct {
 	h float64
 }
 
-func (s *ExpScale) Solve() error {
+func (s *ExponentialScale) Solve() error {
 	s.h = s.Domain[0]
 	s.a = s.Range[0]
 	s.b = math.Pow(s.Range[1]/s.Range[0], 1/(s.Domain[1]-s.h))
 	return nil
 }
 
-func (s *ExpScale) String() string {
+func (s *ExponentialScale) String() string {
 	return s.Formula()
 }
 
-func (s *ExpScale) Formula() string {
+func (s *ExponentialScale) Formula() string {
 	return fmt.Sprintf("f(x) = %f * %f ^ (x - %f)", s.a, s.b, s.h)
 }
 
-func (s *ExpScale) FormulaOf(x float64) string {
+func (s *ExponentialScale) FormulaOf(x float64) string {
 	return fmt.Sprintf("f(%f) = %f * %f ^ (%f - %f)", x, s.a, s.b, x, s.h)
 }
 
-func (s *ExpScale) Call(x float64) (y float64) {
+func (s *ExponentialScale) Call(x float64) (y float64) {
 	if x < s.Domain[0] {
 		x = s.Domain[0]
 	} else if x > s.Domain[1] {
@@ -53,7 +69,7 @@ func (s *ExpScale) Call(x float64) (y float64) {
 	return y
 }
 
-type LogScale struct {
+type LogarithmicScale struct {
 	Domain [2]float64 `json:"domain"`
 	Range  [2]float64 `json:"range"`
 
@@ -62,7 +78,7 @@ type LogScale struct {
 	a float64
 }
 
-func (s *LogScale) Call(x float64) (y float64) {
+func (s *LogarithmicScale) Call(x float64) (y float64) {
 	if x < s.Domain[0] {
 		x = s.Domain[0]
 	} else if x > s.Domain[1] {
@@ -74,19 +90,19 @@ func (s *LogScale) Call(x float64) (y float64) {
 	return y
 }
 
-func (s *LogScale) String() string {
+func (s *LogarithmicScale) String() string {
 	return s.Formula()
 }
 
-func (s *LogScale) Formula() string {
+func (s *LogarithmicScale) Formula() string {
 	return fmt.Sprintf("f(x) = %f * log(x - %f) + %f", s.a, s.h, s.s)
 }
 
-func (s *LogScale) FormulaOf(x float64) string {
+func (s *LogarithmicScale) FormulaOf(x float64) string {
 	return fmt.Sprintf("f(%f) = %f * log(%f - %f) + %f", x, s.a, x, s.h, s.s)
 }
 
-func (s *LogScale) Solve() error {
+func (s *LogarithmicScale) Solve() error {
 	// f(x) = a * log2(x - h) + s
 	//
 	// log2(1) = 0
@@ -134,7 +150,7 @@ func (s *LinearScale) Call(x float64) (y float64) {
 		x = s.Domain[1]
 	}
 
-	y = s.a * x + s.b
+	y = s.a*x + s.b
 	return y
 }
 
@@ -150,8 +166,6 @@ func (s *LinearScale) FormulaOf(x float64) string {
 	return fmt.Sprintf("f(%f) = %f * %f + %f", x, s.a, x, s.b)
 }
 
-
-
 // see also: http://www.vb-helper.com/howto_find_quadratic_curve.html
 type QuadraticScale struct {
 	Domain [3]float64 `json:"domain"`
@@ -179,7 +193,7 @@ func (s *QuadraticScale) Call(x float64) (y float64) {
 	}
 
 	// y = a * log(x - h) + s
-	y = s.a * math.Pow(x, 2) + s.b * x + s.c
+	y = s.a*math.Pow(x, 2) + s.b*x + s.c
 	return y
 }
 
@@ -194,3 +208,100 @@ func (s *QuadraticScale) Formula() string {
 func (s *QuadraticScale) FormulaOf(x float64) string {
 	return fmt.Sprintf("f(%f) = %f * %f ^ 2 + %f * %f + %f", x, s.a, x, s.b, x, s.c)
 }
+
+type SlideRule struct {
+	// Scale type could be one of "log", "exp", "linear", "quadratic"
+	// this is similar to the d3.scale
+	LinearScale    *LinearScale      `json:"linear"`
+	LogScale       *LogarithmicScale `json:"log"`
+	ExpScale       *ExponentialScale `json:"exp"`
+	QuadraticScale *QuadraticScale   `json:"quadratic"`
+}
+
+func (rule *SlideRule) Scale() (Scale, error) {
+	if rule.LogScale != nil {
+		return rule.LogScale, nil
+	}
+
+	if rule.ExpScale != nil {
+		return rule.ExpScale, nil
+	}
+
+	if rule.LinearScale != nil {
+		return rule.LinearScale, nil
+	}
+
+	if rule.QuadraticScale != nil {
+		return rule.QuadraticScale, nil
+	}
+
+	return nil, errors.New("no any scale is defined")
+}
+
+// ScaleQuantity defines the scale DSL for strategy, e.g.,
+//
+// scaleQuantity:
+//   byPrice:
+//     exp:
+//       domain: [10_000, 50_000]
+//       range: [0.01, 1.0]
+//
+// and
+//
+// scaleQuantity:
+//   byVolume:
+//     linear:
+//       domain: [10_000, 50_000]
+//       range: [0.01, 1.0]
+type ScaleQuantity struct {
+	ByPrice  *SlideRule `json:"byPrice"`
+	ByVolume *SlideRule `json:"byVolume"`
+}
+
+func (q *ScaleQuantity) Scale(price float64, volume float64) (quantity float64, err error) {
+	if q.ByPrice != nil {
+		quantity, err = q.ScaleByPrice(price)
+		return
+	} else if q.ByVolume != nil {
+		quantity, err = q.ScaleByVolume(volume)
+	} else {
+		err = errors.New("either price or volume scale is not defined")
+	}
+	return
+}
+
+// ScaleByPrice scale quantity by the given price
+func (q *ScaleQuantity) ScaleByPrice(price float64) (float64, error) {
+	if q.ByPrice == nil {
+		return 0, errors.New("byPrice scale is not defined")
+	}
+
+	scale, err := q.ByPrice.Scale()
+	if err != nil {
+		return 0, err
+	}
+
+	if err := scale.Solve() ; err != nil {
+		return 0, err
+	}
+
+	return scale.Call(price), nil
+}
+
+// ScaleByVolume scale quantity by the given volume
+func (q *ScaleQuantity) ScaleByVolume(volume float64) (float64, error) {
+	if q.ByVolume == nil {
+		return 0, errors.New("byVolume scale is not defined")
+	}
+
+	scale, err := q.ByVolume.Scale()
+	if err != nil {
+		return 0, err
+	}
+
+	if err := scale.Solve() ; err != nil {
+		return 0, err
+	}
+
+	return scale.Call(volume), nil
+}

pkg/bbgo/scale_test.go

@@ -10,7 +10,7 @@ import (
 
 func TestExpScale(t *testing.T) {
 	// graph see: https://www.desmos.com/calculator/ip0ijbcbbf
-	scale := ExpScale{
+	scale := ExponentialScale{
 		Domain: [2]float64{1000, 2000},
 		Range:  [2]float64{0.001, 0.01},
 	}
@@ -30,7 +30,7 @@ func TestExpScale(t *testing.T) {
 
 func TestLogScale(t *testing.T) {
 	// see https://www.desmos.com/calculator/q1ufxx5gry
-	scale := LogScale{
+	scale := LogarithmicScale{
 		Domain: [2]float64{1000, 2000},
 		Range:  [2]float64{0.001, 0.01},
 	}

pkg/strategy/grid/strategy.go

@@ -57,6 +57,7 @@ type Strategy struct {
 
 	// Quantity is the quantity you want to submit for each order.
 	Quantity      fixedpoint.Value    `json:"quantity,omitempty"`
+	ScaleQuantity *bbgo.ScaleQuantity `json:"scaleQuantity,omitempty"`
 
 	// FixedAmount is used for fixed amount (dynamic quantity) if you don't want to use fixed quantity.
 	FixedAmount fixedpoint.Value `json:"amount,omitempty" yaml:"amount"`
@@ -120,14 +121,24 @@ func (s *Strategy) generateGridSellOrders(session *bbgo.ExchangeSession) ([]type
 
 	var orders []types.SubmitOrder
 	for price := startPrice; s.LowerPrice <= price && price <= s.UpperPrice; price += gridSpread {
-		quantity := s.Quantity
-		if s.FixedAmount > 0 {
+		var quantity fixedpoint.Value
+		if s.Quantity > 0 {
+			quantity = s.Quantity
+		} else if s.ScaleQuantity != nil {
+			qf, err := s.ScaleQuantity.Scale(price.Float64(), 0)
+			if err != nil {
+				return nil, err
+			}
+			quantity = fixedpoint.NewFromFloat(qf)
+		} else if s.FixedAmount > 0 {
 			quantity = s.FixedAmount.Div(price)
 		}
 
 		// quoteQuantity := price.Mul(quantity)
 		if baseBalance.Available < quantity {
-			return orders, fmt.Errorf("base balance %f is not enough, stop generating orders", baseBalance.Available.Float64())
+			return orders, fmt.Errorf("base balance %s %f is not enough, stop generating sell orders",
+				baseBalance.Currency,
+				baseBalance.Available.Float64())
 		}
 
 		orders = append(orders, types.SubmitOrder{
@@ -185,14 +196,23 @@ func (s *Strategy) generateGridBuyOrders(session *bbgo.ExchangeSession) ([]types
 
 	var orders []types.SubmitOrder
 	for price := startPrice; s.LowerPrice <= price && price <= s.UpperPrice; price -= gridSpread {
-		quantity := s.Quantity
-		if s.FixedAmount > 0 {
+		var quantity fixedpoint.Value
+		if s.Quantity > 0 {
+			quantity = s.Quantity
+		} else if s.ScaleQuantity != nil {
+			qf, err := s.ScaleQuantity.Scale(price.Float64(), 0)
+			if err != nil {
+				return nil, err
+			}
+			quantity = fixedpoint.NewFromFloat(qf)
+		} else if s.FixedAmount > 0 {
 			quantity = s.FixedAmount.Div(price)
 		}
 
 		quoteQuantity := price.Mul(quantity)
 		if balance.Available < quoteQuantity {
-			return orders, fmt.Errorf("quote balance %f is not enough for %f, stop generating orders",
+			return orders, fmt.Errorf("quote balance %s %f is not enough for %f, stop generating buy orders",
+				balance.Currency,
 				balance.Available.Float64(),
 				quoteQuantity.Float64())
 		}
@@ -324,7 +344,6 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 
 	log.Infof("position: %+v", position)
 
-
 	instanceID := fmt.Sprintf("grid-%s-%d", s.Symbol, s.GridNum)
 	s.groupID = generateGroupID(instanceID)
 	log.Infof("using group id %d from fnv(%s)", s.groupID, instanceID)

pkg/strategy/support/strategy.go

@@ -36,6 +36,8 @@ type Strategy struct {
 	MinVolume             fixedpoint.Value                `json:"minVolume"`
 	MarginOrderSideEffect types.MarginOrderSideEffectType `json:"marginOrderSideEffect"`
 	Targets               []Target                        `json:"targets"`
+
+	ScaleQuantity *bbgo.ScaleQuantity `json:"scaleQuantity"`
 }
 
 func (s *Strategy) ID() string {
@@ -56,8 +58,8 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 		s.MovingAverageWindow = 99
 	}
 
-	if s.Quantity == 0 {
-		return fmt.Errorf("quantity can not be zero")
+	if s.Quantity == 0 && s.ScaleQuantity == nil {
+		return fmt.Errorf("quantity or scaleQuantity can not be zero")
 	}
 
 	if s.MinVolume == 0 {
@@ -95,7 +97,17 @@ func (s *Strategy) Run(ctx context.Context, orderExecutor bbgo.OrderExecutor, se
 
 		s.Notify("found support: close price %f is under EMA %f, volume %f > minimum volume %f", closePrice, ema.Last(), kline.Volume, s.MinVolume.Float64())
 
-		quantity := s.Quantity.Float64()
+		var quantity float64
+		if s.Quantity > 0 {
+			quantity = s.Quantity.Float64()
+		} else if s.ScaleQuantity != nil {
+			var err error
+			quantity, err = s.ScaleQuantity.Scale(closePrice, kline.Volume)
+			if err != nil {
+				log.WithError(err).Error(err.Error())
+				return
+			}
+		}
 
 		orderForm := types.SubmitOrder{
 			Symbol:           s.Symbol,