/**
* Builds a BDD which is true for all the possible assignments to the variable blocks that makes
* the blocks equal.
*
* <p>Compare to fdd_equals/fdd_equ.
*
* @param that
* @return BDD
*/
public BDD buildEquals(BDDDomain that) {
if (!this.size().equals(that.size())) {
throw new BDDException(
"Size of "
+ this
+ " != size of that "
+ that
+ "( "
+ this.size()
+ " vs "
+ that.size()
+ ")");
}
BDDFactory factory = getFactory();
BDD e = factory.universe();
int[] this_ivar = this.vars();
int[] that_ivar = that.vars();
for (int n = 0; n < this.varNum(); n++) {
BDD a = factory.ithVar(this_ivar[n]);
BDD b = factory.ithVar(that_ivar[n]);
a.biimpWith(b);
e.andWith(a);
}
return e;
}
public BDD buildAdd(BDDDomain that, int bits, long value) {
if (bits > this.varNum() || bits > that.varNum())
throw new BDDException(
"Number of bits requested ("
+ bits
+ ") is larger than domain sizes "
+ this.varNum()
+ ","
+ that.varNum());
BDDFactory bdd = getFactory();
if (value == 0L) {
BDD result = bdd.universe();
int n;
for (n = 0; n < bits; n++) {
BDD b = bdd.ithVar(this.ivar[n]);
b.biimpWith(bdd.ithVar(that.ivar[n]));
result.andWith(b);
}
for (; n < Math.max(this.varNum(), that.varNum()); n++) {
BDD b = (n < this.varNum()) ? bdd.nithVar(this.ivar[n]) : bdd.one();
b.andWith((n < that.varNum()) ? bdd.nithVar(that.ivar[n]) : bdd.one());
result.andWith(b);
}
return result;
}
int[] vars = new int[bits];
System.arraycopy(this.ivar, 0, vars, 0, vars.length);
BDDBitVector y = bdd.buildVector(vars);
BDDBitVector v = bdd.constantVector(bits, value);
BDDBitVector z = y.add(v);
int[] thatvars = new int[bits];
System.arraycopy(that.ivar, 0, thatvars, 0, thatvars.length);
BDDBitVector x = bdd.buildVector(thatvars);
BDD result = bdd.one();
int n;
for (n = 0; n < x.size(); n++) {
BDD b = x.bitvec[n].biimp(z.bitvec[n]);
result.andWith(b);
}
for (; n < Math.max(this.varNum(), that.varNum()); n++) {
BDD b = (n < this.varNum()) ? bdd.nithVar(this.ivar[n]) : bdd.one();
b.andWith((n < that.varNum()) ? bdd.nithVar(that.ivar[n]) : bdd.one());
result.andWith(b);
}
x.free();
y.free();
z.free();
v.free();
return result;
}