C++ Formula::eval方法代码示例

//
// Function: MULTIPLE.OPERATIONS
//
Value func_multiple_operations(valVector args, ValueCalc *, FuncExtra *e)
{
    if (args.count() != 3 && args.count() != 5)
        return Value::errorVALUE(); // invalid number of parameters

    for (int i = 0; i < args.count(); i++) {
        if (e->ranges[i].col1 == -1 || e->ranges[i].row1 == -1)
            return Value::errorVALUE();
    }

    CellStorage *s = e->sheet->cellStorage();

    // get formula to evaluate
    int formulaCol = e->ranges[0].col1;
    int formulaRow = e->ranges[0].row1;
    Formula formula = s->formula(formulaCol, formulaRow);
    if (!formula.isValid())
        return Value::errorVALUE();

    CellIndirection cellIndirections;
    cellIndirections.insert(Cell(e->sheet, e->ranges[1].col1, e->ranges[1].row1), Cell(e->sheet, e->ranges[2].col1, e->ranges[2].row1));
    if (args.count() > 3) {
        cellIndirections.insert(Cell(e->sheet, e->ranges[3].col1, e->ranges[3].row1), Cell(e->sheet, e->ranges[4].col1, e->ranges[4].row1));
    }

    return formula.eval(cellIndirections);
}

Value TestTextFunctions::evaluate(const QString& formula, Value& ex)
{
    Formula f;
    QString expr = formula;
    if (expr[0] != '=')
        expr.prepend('=');
    f.setExpression(expr);
    Value result = f.eval();

    if (result.isFloat() && ex.isInteger())
        ex = Value(ex.asFloat());
    if (result.isInteger() && ex.isFloat())
        result = Value(result.asFloat());

    return result;
}

void GoalSeekDialog::startCalc(double _start, double _goal)
{
    d->widget.label4->setText(i18n("Starting..."));
    d->widget.label5->setText(i18n("Iteration:"));

    // lets be optimistic
    bool ok = true;

    // TODO: make this configurable
    double eps = 0.0000001;

    double startA = 0.0, startB;
    double resultA, resultB;

    // save old value
    if (d->firstRun) {
        d->firstRun = false;
        d->oldSource = numToDouble(d->sourceCell.value().asFloat());
    }
    resultA = numToDouble(d->targetCell.value().asFloat()) - _goal;

    // initialize start value
    startB = _start;
    double x = startB + 0.5;

    int iterations = d->maxIter;
    const Formula formula = d->targetCell.formula();

    // while the result is not close enough to zero
    // or while the max number of iterations is not reached...
    while (fabs(resultA) > eps && (iterations >= 0)) {
        startA = startB;
        startB = x;

        d->sourceCell.setValue(Value(startA));
        const double targetValueA = numToDouble(formula.eval().asFloat());
        resultA = targetValueA - _goal;
//         debugSheets << "Target A:" << targetValueA << "," << d->targetCell.userInput() << "Calc:" << resultA;

        d->sourceCell.setValue(Value(startB));
        const double targetValueB = numToDouble(formula.eval().asFloat());
        resultB = targetValueB - _goal;
//         debugSheets << "Target B:" << targetValueB << "," << d->targetCell.userInput() << "Calc:" << resultB;

//         debugSheets <<"Iteration:" << iterations <<", StartA:" << startA
//                  << ", ResultA: " << resultA << " (eps: " << eps << "), StartB: "
//                  << startB << ", ResultB: " << resultB << endl;


        // find zero with secant method (rough implementation was provided by Franz-Xaver Meier):
        // if the function returns the same for two different
        // values we have something like a horizontal line
        // => can't get zero.
        if (resultB == resultA) {
//         debugSheets <<" resultA == resultB";
            if (fabs(resultA) < eps) {
                ok = true;
                break;
            }

            ok = false;
            break;
        }

        // Point of intersection of secant with x-axis
        x = (startA * resultB - startB * resultA) / (resultB - resultA);

        if (fabs(x) > 100000000) {
//             debugSheets <<"fabs(x) > 100000000:" << x;
            ok = false;
            break;
        }

//         debugSheets <<"X:" << x <<", fabs (resultA):" << fabs(resultA) <<", Real start:" << startA <<", Real result:" << resultA <<", Iteration:" << iterations;

        --iterations;
        if (iterations % 20 == 0)
            d->widget.newValue->setText(QString::number(iterations));
    }

    d->widget.label5->setText(i18n("New value:"));
    if (ok) {
        d->sourceCell.setValue(Value(startA));

        d->widget.label4->setText(i18n("Goal seeking with cell %1 found a solution:",
                                       d->widget.selector3->textEdit()->toPlainText()));
        d->widget.newValue->setText(d->selection->activeSheet()->map()->calculationSettings()->locale()->formatNumber(startA));
        d->widget.currentValue->setText(d->selection->activeSheet()->map()->calculationSettings()->locale()->formatNumber(d->oldSource));
    } else {
        // restore the old value
        d->sourceCell.setValue(Value(d->oldSource));
        d->widget.label4->setText(i18n("Goal seeking with cell %1 has found NO solution.",
                                       d->widget.selector3->textEdit()->toPlainText()));
        d->widget.newValue->setText("");
        d->widget.currentValue->setText(d->selection->activeSheet()->map()->calculationSettings()->locale()->formatNumber(d->oldSource));
    }

    enableButtonOk(ok);
    enableButtonCancel(true);
}