// check simple summation
public void CheckSimpleSummation()
{
string s = "d3u(x-2*h) - du(x-h)";
Assert.True(FiniteDifference.GetFiniteDifferenceByOrderAndMinH(3, -2) -
FiniteDifference.GetFiniteDifferenceByOrderAndMinH(1, -1)
== DifferenceExpressionEvaluator.Evaluate(s));
}
// check summation of multiple summands with coefficients
public void CheckSummation()
{
string s = " d3 u(x-2*h) - 2 * du(x-h) + u(x+2*h) - 1 * d^2 u(x) ";
Assert.True(FiniteDifference.GetFiniteDifferenceByOrderAndMinH(3, -2)
- 2 * FiniteDifference.GetFiniteDifferenceByOrderAndMinH(1, -1)
+ FiniteDifference.GetFiniteDifferenceByOrderAndMinH(0, 2)
- FiniteDifference.GetFiniteDifferenceByOrder(2)
== DifferenceExpressionEvaluator.Evaluate(s));
s = " - d^3u(x-2*h) - 2 * du(x-h) + u(x+2*h) - 1 * d^2 u(x) ";
Assert.True(-FiniteDifference.GetFiniteDifferenceByOrderAndMinH(3, -2)
- 2 * FiniteDifference.GetFiniteDifferenceByOrderAndMinH(1, -1)
+ FiniteDifference.GetFiniteDifferenceByOrderAndMinH(0, 2)
- FiniteDifference.GetFiniteDifferenceByOrder(2)
== DifferenceExpressionEvaluator.Evaluate(s));
}
// check whether the DifferenceExpressionEvaluator provide valid error info on summation
public void CheckSummationErrors()
{
// check summation errors
try
{
DifferenceExpressionEvaluator.Evaluate("++1d^5u(x-242h)+3*du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("++1d^5u(x-242h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("1d^5u(x-242h)+-du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("+-du(x-4223h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("+1 d^5u(x-242h)+2+2du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("+2+2du(x-4223h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("1 d^5u(x-24+2)2h)+2*du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("1 d^5u(x-24+2)", e.Message);
}
}
// check whether the DifferenceExpressionEvaluator provide valid error info on big numbers
public void CheckOverflowErrors()
{
// check arg overflow
try
{
DifferenceExpressionEvaluator.Evaluate("-d^5u(x-242h)+3*du(x-42342341423h)");
Assert.True(false); // report error here
}
catch (OverflowException e)
{
Assert.Equal("+3*du(x-42342341423h)", e.Message);
}
// check order overflow
try
{
DifferenceExpressionEvaluator.Evaluate("-d^55646u(x-242h)+3*du(x-4223h)");
Assert.True(false); // report error here
}
catch (OverflowException e)
{
Assert.Equal("-d^55646u(x-242h)", e.Message);
}
}
// check whether the DifferenceExpressionEvaluator provide valid error info on multiplication
public void CheckMultiplicationErrors()
{
// check multiplication errors
try
{
DifferenceExpressionEvaluator.Evaluate("1 1d^5u(x-242h)+3*du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("1 1d^5u(x-242h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("1d^5u(x-242h)+*du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("+*du(x-4223h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("1 d^5u(x-242h)+2,3.3 * d u(x-4223h) ");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("+2,3.3 * d u(x-4223h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("-.d^5u(x-242h)+2,3.3 * d u(x-4223h) ");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("-.d^5u(x-242h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("-.2d^5u(x-242h)+2,3.3 * d u(x-4223h) ");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("-.2d^5u(x-242h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("-2.d^5u(x-242h)+2,3.3 * d u(x-4223h) ");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("-2.d^5u(x-242h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("1 d^5u(x-242h)+2,3. *du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("+2,3. *du(x-4223h)", e.Message);
}
try
{
DifferenceExpressionEvaluator.Evaluate("1 d^5u(x-242h)+2*2*du(x-4223h)");
Assert.True(false); // report error here
}
catch (FormatException e)
{
Assert.Equal("+2*2*du(x-4223h)", e.Message);
}
}
// check multiplication
public void CheckSingleDifferenceMultiplication()
{
string s = " -20.2 * d3u (x-2*h) ";
Assert.True(-20.2 * FiniteDifference.GetFiniteDifferenceByOrderAndMinH(3, -2) == DifferenceExpressionEvaluator.Evaluate(s));
s = " 20,2d3u(x-2*h)";
Assert.True(20.2 * FiniteDifference.GetFiniteDifferenceByOrderAndMinH(3, -2) == DifferenceExpressionEvaluator.Evaluate(s));
}
// test simple FiniteDifference parsing
public void CheckSingleDifference()
{
string s = "d3u(x-h)";
Assert.True(FiniteDifference.GetFiniteDifferenceByOrderAndMinH(3, -1) == DifferenceExpressionEvaluator.Evaluate(s));
}
