/**
* {@inheritDoc}
*
* @return a {@link String} with the format <code>{p2-p1, p3-p1, ..., p(n-1)-p1}</code>, where
* {@code pi} corresponds to the pitch of the i-th note inside the n-gram. The {@link String}
* {@code "null"} is returned if the n-gram is {@code null}.
*/
@Override
public String getNGramId(NGram g) {
if (g == null) return "null";
String res = "{";
for (int i = 1; i < g.size(); i++) res += (g.get(i).getPitch() - g.get(0).getPitch()) + " ";
return res.trim() + "}";
}
/** {@inheritDoc} */
@Override
public double compare(NGram g1, NGram g2) {
if (g1 == null) g1 = g2.getNullSpan();
if (g2 == null) g2 = g1.getNullSpan();
if (g1.size() != 3)
throw new IllegalArgumentException(this.getName() + " only supports n-grams with 3 notes.");
if (this.getNGramId(g1).equals(this.getNGramId(g2))) return 0;
PolynomialFunction p1 = new PolynomialFunction(new double[] {0});
PolynomialFunction p2 = new PolynomialFunction(new double[] {0});
for (int i = 1; i < g1.size(); i++) {
PolynomialFunction basis = UniformBSpline.BASIS_FUNCTIONS[g1.size() - 1][i - 1];
p1 =
p1.add(
basis.multiply(
new PolynomialFunction(
new double[] {g1.get(g1.size() - i).getPitch() - g1.get(0).getPitch()})));
p2 =
p2.add(
basis.multiply(
new PolynomialFunction(
new double[] {g2.get(g2.size() - i).getPitch() - g2.get(0).getPitch()})));
}
PolynomialFunction p1_ = p1.polynomialDerivative();
PolynomialFunction p2_ = p2.polynomialDerivative();
/*
double p1_0 = Math.signum(p1_.value(0));
double p1_1 = Math.signum(p1_.value(1));
double p2_0 = Math.signum(p2_.value(0));
double p2_1 = Math.signum(p2_.value(1));
if(p1_0 == p2_0){ // same at 0
if(p1_1 == p2_1) // same at 1
return -this.dMin;
else if(p1_1*p2_1<0) // opposite at 1
return -this.dMed;
else // some flat at 1
return -this.dMed;
}else if(p1_0*p2_0 < 0) { // opposite at 0
if(p1_1 == p2_1) // same at 1
return -this.dMed;
else if(p1_1*p2_1<0) // opposite at 1
return -this.dMax;
else // some flat at 1
return -this.dMax;
}else { // some flat at 0
if(p1_1 == p2_1) // same at 1
return -this.dMed;
else if(p1_1*p2_1<0) // opposite at 1
return -this.dMax;
else // some flat at 1
return -this.dMax;
}*/
double p1_0 = p1_.value(0);
double p1_1 = p1_.value(1);
double p2_0 = p2_.value(0);
double p2_1 = p2_.value(1);
// TODO: this similarity function is not symmetric
if (p1_0 <= 0 && p1_1 >= 0) { // p1 is \/
if (p2_0 <= 0 && p2_1 >= 0) // p2 is \/
return -this.dMin;
else if (p2_0 >= 0 && p2_1 <= 0) // p2 is /\
return -this.dMax;
else return -this.dMed;
}
if (p1_0 >= 0 && p1_1 <= 0) { // p1 is /\
if (p2_0 >= 0 && p2_1 <= 0) // p2 is /\
return -this.dMin;
else if (p2_0 <= 0 && p2_1 >= 0) // p2 is \/
return -this.dMax;
else return -this.dMed;
}
if (p1_0 >= 0 && p1_1 >= 0) { // p1 is /
if (p2_0 >= 0 && p2_1 >= 0) // p2 is /
return -this.dMin;
else if (p2_0 <= 0 && p2_1 <= 0) // p2 is \
return -this.dMax;
else return -this.dMed;
}
if (p1_0 <= 0 && p1_1 <= 0) { // p1 is \
if (p2_0 <= 0 && p2_1 <= 0) // p2 is \
return -this.dMin;
else if (p2_0 >= 0 && p2_1 >= 0) // p2 is /
return -this.dMax;
else return -this.dMed;
}
return -this.dMin;
}