 Usage:  setmaskl(data, p_matrix, color_num, art, thick)   
 
 Input:

  data                   a data matrix 
                         
                         
  p_matrix               a matrix of integers that tells setmaskl which points to connect. Each row of the matrix 
                         corresponds to one line. For instance, if you want to draw three lines then 
                         p_matrix needs to have three rows. Each row must have the same number of elements. 
                         A row consisting of the integers 1, 3 and 5 will result in a line that connects the 
                         1st, 3rd and 5th point of the datamatrix. Use 0 to interrupt lines. 
                         That is the row 1,3,0,5,6 will connect the 1st and the 3rd point , then interrupt the line and continue it by 
                         connecting the 5th and the 6th point. 
                         
                         
                         
                         
                         
  color_num              a column vector of integers, that has the same number or rows as p_matrix. 
                         Each element specifies the color of the corresponding line from p_matrix. 
                         0 is black, 
                         1 is blue, 
                         2 is green, 
                         3 is cyan, 
                         4 is red, 
                         5 is magenta, 
                         6 is yellow, 
                         7 is white 
                         
                         
  art                    a column vector of integers, that has the same number of rows as p_matrix. 
                         Each element specifies the appearance of the corresponding line from p_matrix. 
                         0 : invisible line, 
                         1 : solid line, 
                         2 : finely dashed line, 
                         3 : less finely dashed line, 
                         4 : even less finely dashed line, 
                         and so on. 
                         
                         
  thick                  a column vector of integers, that has the same number or rows as p_matrix. 
                         Each element specifies the thickness of the corresponding line from p_matrix. 
                         0 will produce the thinnest line and increasing integers produce 
                         lines of increasing thickness. 15 produces the thickest line possible. 
                         
                         
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(C) MD*TECH Method and Data Technologies, 17.8.2000
