* <p> The resulting instance may or may not satisfy all facts, and should be checked for consistency.
*/
public void init(Field field, SimTupleset value) throws Err {
if (value==null) { sfs.remove(field); return; }
if (!value.empty() && value.arity()!=field.type().arity()) throw new ErrorType("Evaluator encountered an error: field "+field.label+" arity must not be " + value.arity());
if (field.defined) throw new ErrorAPI("Evaluator cannot prebind the value of a defined field.");
sfs.put(field, value);
cacheUNIV = null;
cacheSTRING = null;
cacheForConstants.clear();
}