/*! Black style formula when forward is normal rather than
* log-normal. This is essentially the model of Bachelier.
*
* \warning Bachelier model needs absolute volatility, not
* percentage volatility. Standard deviation is
* absoluteVolatility*sqrt(timeToMaturity)
*/
public static double bachelierBlackFormula(Option.Type optionType,
double strike,
double forward,
double stdDev,
double discount = 1.0)
{
QL_REQUIRE(stdDev >= 0.0, () =>
"stdDev (" + stdDev + ") must be non-negative");
QL_REQUIRE(discount > 0.0, () =>
"discount (" + discount + ") must be positive");
double d = (forward - strike) * (int)optionType, h = d / stdDev;
if (stdDev.IsEqual(0.0))
{
return(discount * Math.Max(d, 0.0));
}
CumulativeNormalDistribution phi = new CumulativeNormalDistribution();
double result = discount * (stdDev * phi.derivative(h) + d * phi.value(h));
QL_REQUIRE(result >= 0.0, () =>
"negative value (" + result + ") for " +
stdDev + " stdDev, " +
optionType + " option, " +
strike + " strike , " +
forward + " forward");
return(result);
}
public double nD2(double strike) // n(d2)
{
double d2_ = 0.0;
double n_d2_ = 0.0; // n(d2)
if (stdDev_ >= Const.QL_EPSILON)
{
if (strike > 0)
{
d2_ = Math.Log(forward_ / strike) / stdDev_ - 0.5 * stdDev_;
CumulativeNormalDistribution f = new CumulativeNormalDistribution();
n_d2_ = f.derivative(d2_);
}
}
return(n_d2_);
}
public AmericanPayoffAtHit(double spot, double discount, double dividendDiscount, double variance, StrikedTypePayoff payoff)
{
spot_ = spot;
discount_ = discount;
dividendDiscount_ = dividendDiscount;
variance_ = variance;
Utils.QL_REQUIRE(spot_ > 0.0, () => "positive spot value required");
Utils.QL_REQUIRE(discount_ > 0.0, () => "positive discount required");
Utils.QL_REQUIRE(dividendDiscount_ > 0.0, () => "positive dividend discount required");
Utils.QL_REQUIRE(variance_ >= 0.0, () => "negative variance not allowed");
stdDev_ = Math.Sqrt(variance_);
Option.Type type = payoff.optionType();
strike_ = payoff.strike();
log_H_S_ = Math.Log(strike_ / spot_);
double n_d1;
double n_d2;
double cum_d1_;
double cum_d2_;
if (variance_ >= Const.QL_EPSILON)
{
if (discount_.IsEqual(0.0) && dividendDiscount_.IsEqual(0.0))
{
mu_ = -0.5;
lambda_ = 0.5;
}
else if (discount_.IsEqual(0.0))
{
Utils.QL_FAIL("null discount not handled yet");
}
else
{
mu_ = Math.Log(dividendDiscount_ / discount_) / variance_ - 0.5;
lambda_ = Math.Sqrt(mu_ * mu_ - 2.0 * Math.Log(discount_) / variance_);
}
D1_ = log_H_S_ / stdDev_ + lambda_ * stdDev_;
D2_ = D1_ - 2.0 * lambda_ * stdDev_;
CumulativeNormalDistribution f = new CumulativeNormalDistribution();
cum_d1_ = f.value(D1_);
cum_d2_ = f.value(D2_);
n_d1 = f.derivative(D1_);
n_d2 = f.derivative(D2_);
}
else
{
// not tested yet
mu_ = Math.Log(dividendDiscount_ / discount_) / variance_ - 0.5;
lambda_ = Math.Sqrt(mu_ * mu_ - 2.0 * Math.Log(discount_) / variance_);
if (log_H_S_ > 0)
{
cum_d1_ = 1.0;
cum_d2_ = 1.0;
}
else
{
cum_d1_ = 0.0;
cum_d2_ = 0.0;
}
n_d1 = 0.0;
n_d2 = 0.0;
}
switch (type)
{
// up-and-in cash-(at-hit)-or-nothing option
// a.k.a. american call with cash-or-nothing payoff
case Option.Type.Call:
if (strike_ > spot_)
{
alpha_ = 1.0 - cum_d1_; // N(-d1)
DalphaDd1_ = -n_d1; // -n( d1)
beta_ = 1.0 - cum_d2_; // N(-d2)
DbetaDd2_ = -n_d2; // -n( d2)
}
else
{
alpha_ = 0.5;
DalphaDd1_ = 0.0;
beta_ = 0.5;
DbetaDd2_ = 0.0;
}
break;
// down-and-in cash-(at-hit)-or-nothing option
// a.k.a. american put with cash-or-nothing payoff
case Option.Type.Put:
if (strike_ < spot_)
{
alpha_ = cum_d1_; // N(d1)
DalphaDd1_ = n_d1; // n(d1)
beta_ = cum_d2_; // N(d2)
DbetaDd2_ = n_d2; // n(d2)
}
else
{
alpha_ = 0.5;
DalphaDd1_ = 0.0;
beta_ = 0.5;
DbetaDd2_ = 0.0;
}
break;
default:
Utils.QL_FAIL("invalid option type");
break;
}
muPlusLambda_ = mu_ + lambda_;
muMinusLambda_ = mu_ - lambda_;
inTheMoney_ = (type == Option.Type.Call && strike_ < spot_) || (type == Option.Type.Put && strike_ > spot_);
if (inTheMoney_)
{
forward_ = 1.0;
X_ = 1.0;
}
else
{
forward_ = Math.Pow(strike_ / spot_, muPlusLambda_);
X_ = Math.Pow(strike_ / spot_, muMinusLambda_);
}
// Binary Cash-Or-Nothing payoff?
CashOrNothingPayoff coo = payoff as CashOrNothingPayoff;
if (coo != null)
{
K_ = coo.cashPayoff();
}
// Binary Asset-Or-Nothing payoff?
AssetOrNothingPayoff aoo = payoff as AssetOrNothingPayoff;
if (aoo != null)
{
if (inTheMoney_)
{
K_ = spot_;
}
else
{
K_ = aoo.strike();
}
}
}
public BlackCalculator(StrikedTypePayoff payoff, double forward, double stdDev, double discount)
{
strike_ = payoff.strike();
forward_ = forward;
stdDev_ = stdDev;
discount_ = discount;
variance_ = stdDev * stdDev;
Utils.QL_REQUIRE(forward > 0.0, () => "positive forward value required: " + forward + " not allowed");
Utils.QL_REQUIRE(stdDev >= 0.0, () => "non-negative standard deviation required: " + stdDev + " not allowed");
Utils.QL_REQUIRE(discount > 0.0, () => "positive discount required: " + discount + " not allowed");
if (stdDev_ >= Const.QL_EPSILON)
{
if (strike_.IsEqual(0.0))
{
n_d1_ = 0.0;
n_d2_ = 0.0;
cum_d1_ = 1.0;
cum_d2_ = 1.0;
}
else
{
D1_ = Math.Log(forward / strike_) / stdDev_ + 0.5 * stdDev_;
D2_ = D1_ - stdDev_;
CumulativeNormalDistribution f = new CumulativeNormalDistribution();
cum_d1_ = f.value(D1_);
cum_d2_ = f.value(D2_);
n_d1_ = f.derivative(D1_);
n_d2_ = f.derivative(D2_);
}
}
else
{
if (forward > strike_)
{
cum_d1_ = 1.0;
cum_d2_ = 1.0;
}
else
{
cum_d1_ = 0.0;
cum_d2_ = 0.0;
}
n_d1_ = 0.0;
n_d2_ = 0.0;
}
X_ = strike_;
DXDstrike_ = 1.0;
// the following one will probably disappear as soon as
// super-share will be properly handled
DXDs_ = 0.0;
// this part is always executed.
// in case of plain-vanilla payoffs, it is also the only part
// which is executed.
switch (payoff.optionType())
{
case Option.Type.Call:
alpha_ = cum_d1_; // N(d1)
DalphaDd1_ = n_d1_; // n(d1)
beta_ = -cum_d2_; // -N(d2)
DbetaDd2_ = -n_d2_; // -n(d2)
break;
case Option.Type.Put:
alpha_ = -1.0 + cum_d1_; // -N(-d1)
DalphaDd1_ = n_d1_; // n( d1)
beta_ = 1.0 - cum_d2_; // N(-d2)
DbetaDd2_ = -n_d2_; // -n( d2)
break;
default:
Utils.QL_FAIL("invalid option type");
break;
}
// now dispatch on type.
Calculator calc = new Calculator(this);
payoff.accept(calc);
}
// critical commodity price
public static double criticalPrice(StrikedTypePayoff payoff, double riskFreeDiscount, double dividendDiscount,
double variance, double tolerance)
{
// Calculation of seed value, Si
double n = 2.0 * Math.Log(dividendDiscount / riskFreeDiscount) / (variance);
double m = -2.0 * Math.Log(riskFreeDiscount) / (variance);
double bT = Math.Log(dividendDiscount / riskFreeDiscount);
double qu, Su, h, Si = 0;
switch (payoff.optionType())
{
case Option.Type.Call:
qu = (-(n - 1.0) + Math.Sqrt(((n - 1.0) * (n - 1.0)) + 4.0 * m)) / 2.0;
Su = payoff.strike() / (1.0 - 1.0 / qu);
h = -(bT + 2.0 * Math.Sqrt(variance)) * payoff.strike() /
(Su - payoff.strike());
Si = payoff.strike() + (Su - payoff.strike()) *
(1.0 - Math.Exp(h));
break;
case Option.Type.Put:
qu = (-(n - 1.0) - Math.Sqrt(((n - 1.0) * (n - 1.0)) + 4.0 * m)) / 2.0;
Su = payoff.strike() / (1.0 - 1.0 / qu);
h = (bT - 2.0 * Math.Sqrt(variance)) * payoff.strike() /
(payoff.strike() - Su);
Si = Su + (payoff.strike() - Su) * Math.Exp(h);
break;
default:
Utils.QL_FAIL("unknown option type");
break;
}
// Newton Raphson algorithm for finding critical price Si
double Q, LHS, RHS, bi;
double forwardSi = Si * dividendDiscount / riskFreeDiscount;
double d1 = (Math.Log(forwardSi / payoff.strike()) + 0.5 * variance) /
Math.Sqrt(variance);
CumulativeNormalDistribution cumNormalDist = new CumulativeNormalDistribution();
double K = (!Utils.close(riskFreeDiscount, 1.0, 1000))
? -2.0 * Math.Log(riskFreeDiscount)
/ (variance * (1.0 - riskFreeDiscount))
: 2.0 / variance;
double temp = Utils.blackFormula(payoff.optionType(), payoff.strike(),
forwardSi, Math.Sqrt(variance)) * riskFreeDiscount;
switch (payoff.optionType())
{
case Option.Type.Call:
Q = (-(n - 1.0) + Math.Sqrt(((n - 1.0) * (n - 1.0)) + 4 * K)) / 2;
LHS = Si - payoff.strike();
RHS = temp + (1 - dividendDiscount * cumNormalDist.value(d1)) * Si / Q;
bi = dividendDiscount * cumNormalDist.value(d1) * (1 - 1 / Q) +
(1 - dividendDiscount *
cumNormalDist.derivative(d1) / Math.Sqrt(variance)) / Q;
while (Math.Abs(LHS - RHS) / payoff.strike() > tolerance)
{
Si = (payoff.strike() + RHS - bi * Si) / (1 - bi);
forwardSi = Si * dividendDiscount / riskFreeDiscount;
d1 = (Math.Log(forwardSi / payoff.strike()) + 0.5 * variance)
/ Math.Sqrt(variance);
LHS = Si - payoff.strike();
double temp2 = Utils.blackFormula(payoff.optionType(), payoff.strike(),
forwardSi, Math.Sqrt(variance)) * riskFreeDiscount;
RHS = temp2 + (1 - dividendDiscount * cumNormalDist.value(d1)) * Si / Q;
bi = dividendDiscount * cumNormalDist.value(d1) * (1 - 1 / Q)
+ (1 - dividendDiscount *
cumNormalDist.derivative(d1) / Math.Sqrt(variance))
/ Q;
}
break;
case Option.Type.Put:
Q = (-(n - 1.0) - Math.Sqrt(((n - 1.0) * (n - 1.0)) + 4 * K)) / 2;
LHS = payoff.strike() - Si;
RHS = temp - (1 - dividendDiscount * cumNormalDist.value(-d1)) * Si / Q;
bi = -dividendDiscount *cumNormalDist.value(-d1) * (1 - 1 / Q)
- (1 + dividendDiscount * cumNormalDist.derivative(-d1)
/ Math.Sqrt(variance)) / Q;
while (Math.Abs(LHS - RHS) / payoff.strike() > tolerance)
{
Si = (payoff.strike() - RHS + bi * Si) / (1 + bi);
forwardSi = Si * dividendDiscount / riskFreeDiscount;
d1 = (Math.Log(forwardSi / payoff.strike()) + 0.5 * variance)
/ Math.Sqrt(variance);
LHS = payoff.strike() - Si;
double temp2 = Utils.blackFormula(payoff.optionType(), payoff.strike(),
forwardSi, Math.Sqrt(variance)) * riskFreeDiscount;
RHS = temp2 - (1 - dividendDiscount * cumNormalDist.value(-d1)) * Si / Q;
bi = -dividendDiscount *cumNormalDist.value(-d1) * (1 - 1 / Q)
- (1 + dividendDiscount * cumNormalDist.derivative(-d1)
/ Math.Sqrt(variance)) / Q;
}
break;
default:
Utils.QL_FAIL("unknown option type");
break;
}
return(Si);
}
public AmericanPayoffAtExpiry(double spot, double discount, double dividendDiscount, double variance,
StrikedTypePayoff payoff, bool knock_in = true)
{
spot_ = spot;
discount_ = discount;
dividendDiscount_ = dividendDiscount;
variance_ = variance;
knock_in_ = knock_in;
Utils.QL_REQUIRE(spot_ > 0.0, () => "positive spot value required");
Utils.QL_REQUIRE(discount_ > 0.0, () => "positive discount required");
Utils.QL_REQUIRE(dividendDiscount_ > 0.0, () => "positive dividend discount required");
Utils.QL_REQUIRE(variance_ >= 0.0, () => "negative variance not allowed");
stdDev_ = Math.Sqrt(variance_);
Option.Type type = payoff.optionType();
strike_ = payoff.strike();
forward_ = spot_ * dividendDiscount_ / discount_;
mu_ = Math.Log(dividendDiscount_ / discount_) / variance_ - 0.5;
// binary cash-or-nothing payoff?
CashOrNothingPayoff coo = payoff as CashOrNothingPayoff;
if (coo != null)
{
K_ = coo.cashPayoff();
}
// binary asset-or-nothing payoff?
AssetOrNothingPayoff aoo = payoff as AssetOrNothingPayoff;
if (aoo != null)
{
K_ = forward_;
mu_ += 1.0;
}
log_H_S_ = Math.Log(strike_ / spot_);
double log_S_H_ = Math.Log(spot_ / strike_);
double eta = 0.0;
double phi = 0.0;
switch (type)
{
case Option.Type.Call:
if (knock_in_)
{
// up-and-in cash-(at-expiry)-or-nothing option
// a.k.a. american call with cash-or-nothing payoff
eta = -1.0;
phi = 1.0;
}
else
{
// up-and-out cash-(at-expiry)-or-nothing option
eta = -1.0;
phi = -1.0;
}
break;
case Option.Type.Put:
if (knock_in_)
{
// down-and-in cash-(at-expiry)-or-nothing option
// a.k.a. american put with cash-or-nothing payoff
eta = 1.0;
phi = -1.0;
}
else
{
// down-and-out cash-(at-expiry)-or-nothing option
eta = 1.0;
phi = 1.0;
}
break;
default:
Utils.QL_FAIL("invalid option type");
break;
}
if (variance_ >= Const.QL_EPSILON)
{
D1_ = phi * (log_S_H_ / stdDev_ + mu_ * stdDev_);
D2_ = eta * (log_H_S_ / stdDev_ + mu_ * stdDev_);
CumulativeNormalDistribution f = new CumulativeNormalDistribution();
cum_d1_ = f.value(D1_);
cum_d2_ = f.value(D2_);
n_d1_ = f.derivative(D1_);
n_d2_ = f.derivative(D2_);
}
else
{
if (log_S_H_ * phi > 0)
{
cum_d1_ = 1.0;
}
else
{
cum_d1_ = 0.0;
}
if (log_H_S_ * eta > 0)
{
cum_d2_ = 1.0;
}
else
{
cum_d2_ = 0.0;
}
n_d1_ = 0.0;
n_d2_ = 0.0;
}
switch (type)
{
case Option.Type.Call:
if (strike_ <= spot_)
{
if (knock_in_)
{
// up-and-in cash-(at-expiry)-or-nothing option
// a.k.a. american call with cash-or-nothing payoff
cum_d1_ = 0.5;
cum_d2_ = 0.5;
}
else
{
// up-and-out cash-(at-expiry)-or-nothing option
// already knocked out
cum_d1_ = 0.0;
cum_d2_ = 0.0;
}
n_d1_ = 0.0;
n_d2_ = 0.0;
}
break;
case Option.Type.Put:
if (strike_ >= spot_)
{
if (knock_in_)
{
// down-and-in cash-(at-expiry)-or-nothing option
// a.k.a. american put with cash-or-nothing payoff
cum_d1_ = 0.5;
cum_d2_ = 0.5;
}
else
{
// down-and-out cash-(at-expiry)-or-nothing option
// already knocked out
cum_d1_ = 0.0;
cum_d2_ = 0.0;
}
n_d1_ = 0.0;
n_d2_ = 0.0;
}
break;
default:
Utils.QL_FAIL("invalid option type");
break;
}
inTheMoney_ = (type == Option.Type.Call && strike_ < spot_) ||
(type == Option.Type.Put && strike_ > spot_);
if (inTheMoney_)
{
X_ = 1.0;
Y_ = 1.0;
}
else
{
X_ = 1.0;
if (cum_d2_.IsEqual(0.0))
{
Y_ = 0.0; // check needed on some extreme cases
}
else
{
Y_ = Math.Pow((strike_ / spot_), (2.0 * mu_));
}
}
if (!knock_in_)
{
Y_ *= -1.0;
}
}