Add initial bonding curve implementation

Author: jeffyanta

pkg/solana/currencycreator/curve.go

@@ -0,0 +1,99 @@
+package currencycreator
+
+import (
+	"math"
+	"math/big"
+)
+
+// Note: Generated with Grok 4 based on curve.rs, and not 100% accurate with on-chain program
+
+const defaultPrec = 192
+
+type ExponentialCurve struct {
+	a *big.Float
+	b *big.Float
+	c *big.Float
+}
+
+func expBig(x *big.Float) *big.Float {
+	prec := x.Prec()
+	result := big.NewFloat(1).SetPrec(prec)
+	term := big.NewFloat(1).SetPrec(prec)
+	for i := 1; i < 1000; i++ {
+		term = term.Mul(term, x)
+		term = term.Quo(term, big.NewFloat(float64(i)))
+		old := new(big.Float).Copy(result)
+		result = result.Add(result, term)
+		if term.Cmp(new(big.Float).SetFloat64(0)) == 0 {
+			break
+		}
+		if old.Cmp(result) == 0 {
+			break
+		}
+	}
+	return result
+}
+
+func logBig(y *big.Float) *big.Float {
+	if y.Sign() <= 0 {
+		panic("log of non-positive number")
+	}
+	yf, _ := y.Float64()
+	z := big.NewFloat(math.Log(yf)).SetPrec(y.Prec())
+	for range 50 {
+		expz := expBig(z)
+		adjustment := new(big.Float).Quo(y, expz)
+		z = z.Add(z, adjustment)
+		z = z.Sub(z, big.NewFloat(1))
+	}
+	return z
+}
+
+func (curve *ExponentialCurve) SpotPriceAtSupply(currentSupply *big.Float) *big.Float {
+	cTimesS := new(big.Float).Mul(curve.c, currentSupply)
+	exp := expBig(cTimesS)
+	return new(big.Float).Mul(new(big.Float).Mul(curve.a, curve.b), exp)
+}
+
+func (curve *ExponentialCurve) TokensToValue(currentSupply, tokens *big.Float) *big.Float {
+	newSupply := new(big.Float).Add(currentSupply, tokens)
+	cs := new(big.Float).Mul(curve.c, currentSupply)
+	ns := new(big.Float).Mul(curve.c, newSupply)
+	expCS := expBig(cs)
+	expNS := expBig(ns)
+	abOverC := new(big.Float).Quo(new(big.Float).Mul(curve.a, curve.b), curve.c)
+	diff := new(big.Float).Sub(expNS, expCS)
+	return new(big.Float).Mul(abOverC, diff)
+}
+
+func (curve *ExponentialCurve) ValueToTokens(currentSupply, value *big.Float) *big.Float {
+	abOverC := new(big.Float).Quo(new(big.Float).Mul(curve.a, curve.b), curve.c)
+	expCS := expBig(new(big.Float).Mul(curve.c, currentSupply))
+	term := new(big.Float).Add(new(big.Float).Quo(value, abOverC), expCS)
+	lnTerm := logBig(term)
+	result := new(big.Float).Quo(lnTerm, curve.c)
+	return new(big.Float).Sub(result, currentSupply)
+}
+
+func DefaultExponentialCurve() ExponentialCurve {
+	scale, ok := new(big.Float).SetPrec(defaultPrec).SetString("1000000000000000000") // 10^18
+	if !ok {
+		panic("Invalid scale string")
+	}
+
+	aInt, ok := new(big.Int).SetString("11400230149967394933471", 10)
+	if !ok {
+		panic("Invalid CURVE_A string")
+	}
+
+	bInt, ok := new(big.Int).SetString("877175273521", 10)
+	if !ok {
+		panic("Invalid CURVE_B string")
+	}
+
+	a := new(big.Float).Quo(new(big.Float).SetInt(aInt).SetPrec(defaultPrec), scale)
+	b := new(big.Float).Quo(new(big.Float).SetInt(bInt).SetPrec(defaultPrec), scale)
+	c := new(big.Float).Copy(b)
+
+	return ExponentialCurve{a: a, b: b, c: c}
+}

pkg/solana/currencycreator/curve_test.go

@@ -0,0 +1,59 @@
+package currencycreator
+
+import (
+	"fmt"
+	"math/big"
+	"testing"
+)
+
+func TestCalculateCurveConstants(t *testing.T) {
+	curve := DefaultExponentialCurve()
+
+	// Check R'(0) with tolerance
+	spot0 := curve.SpotPriceAtSupply(big.NewFloat(0))
+	expectedStart := big.NewFloat(0.01)
+	diff := new(big.Float).Sub(spot0, expectedStart)
+	threshold, _ := new(big.Float).SetString("0.0000000001")
+	if diff.Abs(diff).Cmp(threshold) > 0 {
+		t.Errorf("Spot at 0: got %s, expected 0.01", spot0.Text('f', 18))
+	}
+
+	// Check R'(21000000) with tolerance
+	supplyEnd := big.NewFloat(21000000)
+	spotEnd := curve.SpotPriceAtSupply(supplyEnd)
+	expectedEnd := big.NewFloat(1000000)
+	diff = new(big.Float).Sub(spotEnd, expectedEnd)
+	threshold, _ = new(big.Float).SetString("0.0001")
+	if diff.Abs(diff).Cmp(threshold) > 0 {
+		t.Errorf("Spot at end: got %s, expected 1000000", spotEnd.Text('f', 18))
+	}
+}
+
+func TestGenerateCurveTable(t *testing.T) {
+	t.Skip()
+
+	curve := DefaultExponentialCurve()
+
+	fmt.Println("|------|----------------|----------------------------------|----------------------------|")
+	fmt.Println("| %    | S              | R(S)                             | R'(S)                      |")
+	fmt.Println("|------|----------------|----------------------------------|----------------------------|")
+
+	zero := big.NewFloat(0)
+	buyAmount := big.NewFloat(210000)
+	supply := new(big.Float).Copy(zero)
+
+	for i := 0; i <= 100; i++ {
+		cost := curve.TokensToValue(zero, supply)
+		spotPrice := curve.SpotPriceAtSupply(supply)
+
+		fmt.Printf("| %3d%% | %14s | %32s | %26s |\n",
+			i,
+			supply.Text('f', 0),
+			cost.Text('f', 18),
+			spotPrice.Text('f', 18))
+
+		supply = supply.Add(supply, buyAmount)
+	}
+
+	fmt.Println("|------|----------------|----------------------------------|----------------------------|")
+}