Node_M PlusMinus()
{
Node_M left = Mult();
while (true)
{
//Identify the operation
Operation op = Operation.Null;
if (splitter.current_sign == Sign.Plus)
{
op = Operation.Addition;
}
else if (splitter.current_sign == Sign.Minus)
{
op = Operation.Substraction;
}
//If no plus or minus sign is found
if (op == Operation.Null)
{
return(left);
}
splitter.Move_sign(); //move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
Node_M right = Mult();
//Create a node with a correspondent binary operation
left = new NodeMatrBinary(left, right, op);
}
}
Node_M Mult()
{
//Check whether the current node is a unary operator
Node_M left = Unary();
while (true)
{
//Identify the operation
Operation op = Operation.Null;
if (splitter.current_sign == Sign.Multiply)
{
op = Operation.Multiplication;
}
//If no multiply or divide sign is found
if (op == Operation.Null)
{
return(left);
}
splitter.Move_sign(); //move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
//Check whether the current node is a unary operator
Node_M right = Unary();
//Create a node with a correspondent binary operation
left = new NodeMatrBinary(left, right, op);
}
}
//Method that parses the whole expression, which calls other methods one by one
//in order to build a correct binary tree of expression
public Node_M CheckExpression()
{
Node_M node = PlusMinus();
if (splitter.current_sign != Sign.EOF)
{
Console.WriteLine("Unexpected characters at end of expression");
Environment.Exit(0);
}
return(node);
}
Node_M Part()
{
/*[ 2 0 ; -1 3 ] * [ 2 0 ; -1 3 ]*/
//Matr
if (splitter.current_sign == Sign.MatrOpen)
{
Node_M part = PartMatrOpen();
return(part);
}
//inv
if (splitter.current_sign == Sign.Inv)
{
Node_M part = PartInv();
return(part);
}
//Parenthesis
if (splitter.current_sign == Sign.Open)
{
splitter.Move_sign(); //move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
//Parse sequentially all the expression after the (
Node_M part = PlusMinus();
// Find the )
if (splitter.current_sign != Sign.Close) //if there's no )
{
Console.WriteLine("Missing close parenthesis");
Environment.Exit(0);
}
splitter.Move_sign(); //move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
return(part);
}
//If the sign is not classified
Console.WriteLine($"Unknown sign: {splitter.current_sign}");
throw new SystemException($"Unknown sign: {splitter.current_sign}");
}
Node_M Unary()
{
while (true)
{
//In case of unary plus
//Unary plus doesn't need any operation
if (splitter.current_sign == Sign.Plus)
{
splitter.Move_sign(); //Move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
continue;
}
//In case of unary minus
else if (splitter.current_sign == Sign.Minus)
{
splitter.Move_sign(); //Move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
//Recursive call to find the sequence of unary operators (if exists)
//eg -+--10 = -10
Node_M a = Unary();
//Node for unary operator
return(new NodeMatrUnary(a, Operation.UnaryMinus));
}
//Just return number if no unary operator is found
return(Part());
}
}
Node_M PartInv()
{
//inv([ 2 5 7 ; 6 3 4 ; 5 -2 -3])
splitter.Move_sign(); //move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign(); //skip space
}
if (splitter.current_sign == Sign.Open)
{
splitter.Move_sign();
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign(); //skip space
}
//Parse sequentially all the expression after the (
Node_M inside = PlusMinus();
// Find the )
if (splitter.current_sign != Sign.Close) //if there's no )
{
Console.WriteLine("Missing closing parenthesis");
Environment.Exit(0);
}
else if (splitter.current_sign == Sign.Close)
{
int r = inside.Calculate().GetLength(0);
int c = inside.Calculate().GetLength(1);
double[,] matr = new double[r, c];
for (int i = 0; i < r; i++)
{
for (int j = 0; j < c; j++)
{
matr[i, j] = inside.Calculate()[i, j];
}
}
if (r == c)
{
int n = r;
int t = 0;
double[,] A = new double[r, c * 2];
//Create a copy of array
for (int i = 0; i < n; i++)
{
for (int j = 0; j < n; j++)
{
A[i, j] = matr[i, j];
}
}
double[,] inv = new double[n, n];
if (MatrInv(A, inv, n))
{
Node_M part = new NodeMatr(inv); //create the node with value of matrix
splitter.Move_sign(); //move to the next sign
if (splitter.current_sign == Sign.Space)
{
splitter.Move_sign();
}
return(part);
}
else
{
Console.WriteLine("Impossible to MatrInv");
Environment.Exit(0);
}
}
else
{
Console.WriteLine("Impossible to MatrInv a non-square matrix");
Environment.Exit(0);
}
}
}
else
{
Console.WriteLine("Missing opening parenthesis");
Environment.Exit(0);
}
return(null);
}
