Method Exp

assets/eip-7543/decimal_float.go:96–122

e^a

(_a *Decimal, precision, steps *int256, gas *uint64)

// e^a
func (out *Decimal) Exp(_a *Decimal, precision, steps *int256, gas *uint64) *Decimal {
	a := copyDecimal(_a, gas) // in case out == _a

	// out = 1
	Set(ONE_INT256, &out.c, gas)
	Set(ZERO_INT256, &out.q, gas)

	if a.isZero(gas) {
		return out
	}

	var factorial_inv Decimal
	a_power := copyDecimal(ONE_DECIMAL, gas)
	factorial := copyDecimal(ONE_DECIMAL, gas)
	factorial_next := copyDecimal(ZERO_DECIMAL, gas)

	for i := New(1, gas); Cmp(steps, i, gas) == -1; Add(i, ONE_INT256, i, gas) { // step 0 skipped as out set to 1
		a_power.Mul(a_power, a, precision, gas)                         // a^i
		factorial_next.Add(factorial_next, ONE_DECIMAL, precision, gas) // i++
		factorial.Mul(factorial, factorial_next, precision, gas)        // i!
		factorial_inv.Inv(factorial, precision, gas)                    // 1/i!
		factorial_inv.Mul(&factorial_inv, a_power, precision, gas)      // store a^i/i! in factorial_inv as not needed anymore
		out.Add(out, &factorial_inv, precision, gas)                    // out += a^i/i!
	}

	return out
}

// 0 < _a
func (out *Decimal) Ln(_a *Decimal, precision, steps *int256, gas *uint64) *Decimal {