public void TestXPlus2Equals4()
{
DependentVariable <AlgebrableInt> x = new DependentVariable <AlgebrableInt>();
_(x + 2 == 4);
Assert.AreEqual(2, x.Value);
}
public void TestMultipleEquations()
{
DependentVariable <AlgebrableInt> x = new DependentVariable <AlgebrableInt>();
DependentVariable <AlgebrableInt> y = new DependentVariable <AlgebrableInt>();
_((y + 3) * 6 == 42, x + y == 10);
Assert.AreEqual(6, x.Value);
}
/// <summary>
/// Determines if an expression contains the specified dependent variable.
/// </summary>
/// <returns><c>true</c> if an expression contains the specified dependent variable; otherwise, <c>false</c>.</returns>
/// <param name="expression">The expression to search.</param>
/// <param name="dv">The dependent variable to find.</param>
/// <typeparam name="T">The type of the dependent variable.</typeparam>
public static bool HasDV <T>(Algebrable expression, DependentVariable <T> dv) where T : Algebrable
{
if (expression is AlgebraOperation)
{
return(HasDV((AlgebraOperation)expression, dv));
}
else
{
return(((object)expression) == ((object)dv));
}
}
public void TestFlippingExpressions()
{
DependentVariable <AlgebrableInt> x = new DependentVariable <AlgebrableInt>();
_(x + 2 == 4);
Assert.AreEqual(2, x.Value);
DependentVariable <AlgebrableInt> y = new DependentVariable <AlgebrableInt>();
_(2 + y == 4);
Assert.AreEqual(2, y.Value);
}
public void TestIndependentVariables()
{
IndependentVariable <AlgebrableInt> width = (AlgebrableInt)0;
IndependentVariable <AlgebrableInt> height = (AlgebrableInt)0;
DependentVariable <AlgebrableInt> area = new DependentVariable <AlgebrableInt>();
_(area == width * height);
Assert.AreEqual(0, area.Value);
width.Value = 42;
height.Value = 4;
Assert.AreEqual(168, area.Value);
}
/// <summary>
/// Determines if an expression contains the specified dependent variable.
/// </summary>
/// <returns><c>true</c> if an expression contains the specified dependent variable; otherwise, <c>false</c>.</returns>
/// <param name="expression">The expression to search.</param>
/// <param name="dv">The dependent variable to find.</param>
/// <typeparam name="T">The type of the dependent variable.</typeparam>
public static bool HasDV <T>(AlgebraOperation expression, DependentVariable <T> dv) where T : Algebrable
{
return(HasDV(expression.Left, dv) || HasDV(expression.Right, dv));
}
/// <summary>
/// Solved this equation for the specified dependent variable.
/// </summary>
/// <param name="dv">The dependent variable to solve for.</param>
/// <typeparam name="T">The type of the dependent variable.</typeparam>
public T Solve <T>(DependentVariable <T> dv) where T : Algebrable
{
if (HasDV(Left, dv))
{
if (HasDV(Right, dv))
{
throw new NotImplementedException("A DV on both sides of an equation is not yet supported");
}
else
{
Algebrable left = Left;
Algebrable right = Right;
while (((object)left) != ((object)dv))
{
if (left is AlgebraOperation)
{
AlgebraOperation op = (AlgebraOperation)left;
Algebrable subLeft;
Algebrable subRight;
if (HasDV(op.Left, dv))
{
if (HasDV(op.Right, dv))
{
throw new NotImplementedException("Only 1 DV is currently supported");
}
else
{
subLeft = op.Left;
subRight = op.Right;
}
}
else if (HasDV(op.Right, dv))
{
op = op.Flip;
subLeft = op.Left;
subRight = op.Right;
}
else
{
throw new InvalidOperationException("Internal error");
}
left = subLeft;
right = op.Inverse[right];
}
else
{
throw new NotImplementedException("Unknown equation type");
}
}
return((T)right.Evaluate());
}
}
else if (HasDV(Right, dv))
{
return(Inverse.Solve(dv));
}
else
{
throw new InvalidOperationException("DV does not exist in equation");
}
}