Examples with MeasureOfSingleVariableLinearRealArithmeticConstraintStepSolver com.sri.ai.grinder.sgdpllt.theory.linearrealarithmetic.MeasureOfSingleVariableLinearRealArithmeticConstraintStepSolver used on opensource projects

Example 1 with MeasureOfSingleVariableLinearRealArithmeticConstraintStepSolver

use of com.sri.ai.grinder.sgdpllt.theory.linearrealarithmetic.MeasureOfSingleVariableLinearRealArithmeticConstraintStepSolver in project aic-expresso by aic-sri-international.

the class Measure method get.

public static Rational get(Expression intensionalSetExpression, Context context) {
    Rational result;
    if (Sets.isIntensionalSet(intensionalSetExpression)) {
        IntensionalSet intensionalSet = (IntensionalSet) intensionalSetExpression;
        IndexExpressionsSet indexExpressionsSet = intensionalSet.getIndexExpressions();
        List<Expression> indices = IndexExpressions.getIndices(indexExpressionsSet);
        if (indices.size() == 1) {
            Expression evaluatedResult;
            Expression intensionalSetIndex = indices.get(0);
            Expression intensionalSetHead = intensionalSet.getHead();
            if (!intensionalSetHead.equals(intensionalSetIndex)) {
                throw new UnsupportedOperationException("Index and Head must be the same to calculate the meaure of an Intensional : " + intensionalSet);
            }
            Expression intensionalSetCondition = intensionalSet.getCondition();
            Context intensionalSetContext = context.extendWith(indexExpressionsSet);
            Type indexType = GrinderUtil.getType(intensionalSetIndex, intensionalSetContext);
            if (intensionalSetCondition.equals(false)) {
                // short circuit known empty sets up front.
                evaluatedResult = Expressions.ZERO;
            } else if (indexType instanceof RealExpressoType || indexType instanceof RealInterval) {
                // NOTE : For Reals can always assume the condition is of this type.				
                SingleVariableLinearRealArithmeticConstraint svConstraint = (SingleVariableLinearRealArithmeticConstraint) intensionalSetCondition;
                MeasureOfSingleVariableLinearRealArithmeticConstraintStepSolver realSolver = new MeasureOfSingleVariableLinearRealArithmeticConstraintStepSolver(svConstraint);
                evaluatedResult = realSolver.solve(intensionalSetContext);
            } else if (indexType instanceof FunctionType) {
                if (!intensionalSetCondition.equals(true)) {
                    throw new UnsupportedOperationException("Measure of intensional set with a function type domain currently do not support conditions: " + intensionalSet);
                }
                // measure(co-domain)^measure(domain)
                FunctionType indexFunctionType = (FunctionType) indexType;
                Expression condomainIntensionalSet = constructComponentIntensionalSet(indexFunctionType.getCodomain(), intensionalSet, ZERO, intensionalSetContext);
                Rational codomainMeasure = get(condomainIntensionalSet, intensionalSetContext);
                Rational domainMeasure = Rational.ONE;
                for (Type argDomainType : indexFunctionType.getArgumentTypes()) {
                    Expression argDomainIntensionalSet = constructComponentIntensionalSet(argDomainType, intensionalSet, ZERO, intensionalSetContext);
                    Rational argMeasure = get(argDomainIntensionalSet, intensionalSetContext);
                    domainMeasure = domainMeasure.multiply(argMeasure);
                }
                evaluatedResult = Expressions.makeSymbol(codomainMeasure.pow(domainMeasure.intValueExact()));
            } else if (indexType instanceof TupleType) {
                if (!intensionalSetCondition.equals(true)) {
                    throw new UnsupportedOperationException("Measure of intensional set with a tuple type domain currently do not support conditions: " + intensionalSet);
                }
                // (element_1, ..., element_n) = measure(element_1) * ... * measure(element_n)
                TupleType indexTupleType = (TupleType) indexType;
                Rational elementMeasuresProduct = Rational.ONE;
                for (Type elementType : indexTupleType.getElementTypes()) {
                    Expression elementDomainIntensionalSet = constructComponentIntensionalSet(elementType, intensionalSet, ZERO, intensionalSetContext);
                    Rational elementMeasure = get(elementDomainIntensionalSet, intensionalSetContext);
                    elementMeasuresProduct = elementMeasuresProduct.multiply(elementMeasure);
                }
                evaluatedResult = Expressions.makeSymbol(elementMeasuresProduct);
            } else {
                Expression countingFormula = new DefaultCountingFormula(indexExpressionsSet, intensionalSet.getCondition());
                evaluatedResult = context.getTheory().evaluate(countingFormula, context);
            }
            if (Expressions.isNumber(evaluatedResult)) {
                result = evaluatedResult.rationalValue();
            } else {
                throw new UnsupportedOperationException("Unable to compute a finite measure for: " + intensionalSet + ", got : " + evaluatedResult);
            }
        } else {
            throw new UnsupportedOperationException("Currently only support the measure of single indexed intensional sets: " + intensionalSet);
        }
    } else {
        throw new IllegalArgumentException("Not an intensional set: " + intensionalSetExpression);
    }
    return result;
}