private bool EqualSolutions(LinearSimultaneousEquationsSolution first, LinearSimultaneousEquationsSolution second)
{
var b1 = first.FirstSolution == second.FirstSolution || (Double.IsNaN(first.FirstSolution) && Double.IsNaN(second.FirstSolution));
var b2 = first.SecondSolution == second.SecondSolution || (Double.IsNaN(first.SecondSolution) && Double.IsNaN(second.SecondSolution));
var b3 = first.NoSolution == second.NoSolution;
var b4 = first.InfiniteSolutions == second.InfiniteSolutions;
return(b1 && b2 && b3 && b4);
}
public void TestFindsNoSolution()
{
var firstEquation = new LinearEquation(18, -3, 46);
var secondEquation = new LinearEquation(6, -1, 12);
var coefficients = new List <LinearEquation>()
{
firstEquation, secondEquation
};
bool invalidCoefficients;
var actualSolution = LinearSimultaneousEquationsAnalysisFunctions.CalculateSolution(coefficients, out invalidCoefficients);
var expectedSolution = new LinearSimultaneousEquationsSolution(Double.NaN, Double.NaN, true, false);
Assert.IsTrue(EqualSolutions(expectedSolution, actualSolution));
}
public void TestFindsInfiniteSolutions()
{
var firstEquation = new LinearEquation(18, -3, 45);
var secondEquation = new LinearEquation(6, -1, 15);
var coefficients = new List <LinearEquation>()
{
firstEquation, secondEquation
};
bool invalidCoefficients;
var actualSolution = LinearSimultaneousEquationsAnalysisFunctions.CalculateSolution(coefficients, out invalidCoefficients);
var expectedSolution = new LinearSimultaneousEquationsSolution(Convert.ToDouble(-14) / Convert.ToDouble(6), 1, false, true);
Assert.IsTrue(EqualSolutions(expectedSolution, actualSolution));
}
public void TestFindsUniqueSolution()
{
var firstEquation = new LinearEquation(3, 2, -36);
var secondEquation = new LinearEquation(5, 4, -64);
var coefficients = new List <LinearEquation>()
{
firstEquation, secondEquation
};
bool invalidCoefficients;
var actualSolution = LinearSimultaneousEquationsAnalysisFunctions.CalculateSolution(coefficients, out invalidCoefficients);
var expectedSolution = new LinearSimultaneousEquationsSolution(8, 6, false, false);
Assert.IsTrue(EqualSolutions(expectedSolution, actualSolution));
Assert.IsFalse(invalidCoefficients);
}
// returns true if solution doesn't exist
private bool VerifySolutionIfSolutionExists(List <LinearEquation> coefficients, LinearSimultaneousEquationsSolution solution)
{
var a = coefficients[0].XTerm;
var b = coefficients[0].YTerm;
var c = coefficients[0].ConstantTerm;
var d = coefficients[1].XTerm;
var e = coefficients[1].YTerm;
var f = coefficients[1].ConstantTerm;
var x = solution.FirstSolution;
var y = solution.SecondSolution;
if (solution.NoSolution)
{
return(true);
}
var firstValue = a * x + b * y + c;
var secondValue = d * x + e * y + f;
var firstSatisfied = Math.Abs(firstValue) < 0.001;
var secondSatisfied = Math.Abs(secondValue) < 0.001;
return(firstSatisfied && secondSatisfied);
}