R/dag.letter2.R

In dagR: Directed Acyclic Graphs: Analysis and Data Simulation

dag.letter2<-
  function(dag, letter, alt.symb) ####
  { # function to draw the letters in the DAG;
    # alt.symb is new since v1.1.2;
    # dag.letter2: based on dag.letter, but returning a string and marking
    #             adjusted variables by a preceding underscore;
    
    if(is.null(dag$symbols)) dag$symbols<-rep(NA, length(dag$x));
    
    if(letter==1)
    { if( (alt.symb==FALSE) || (is.na(dag$symbols[1])) ) {
      "X";
    } else dag$symbols[1];
    } else
      if(letter==length(dag$x))
      { if( (alt.symb==FALSE) || (is.na(dag$symbols[letter])) ) {
        "Y";
      } else dag$symbols[letter];
      } else
      {
        i_c<-0; # covariable counter for subscripts
        i_u<-0; # unknown covs counter for...
        for(i1 in 2:letter)
        {
          if(dag$names[i1]=="unknown" || dag$cov.types[i1]==2)
          { i_u<-i_u+1;
          } else
          { i_c<-i_c+1;
          }
        }
        
        if(dag$names[letter]=="unknown" || dag$cov.types[letter]==2) 
        { if( (alt.symb==FALSE) || (is.na(dag$symbols[letter])) )
        { paste0("U", i_u);
        } else
        { dag$symbols[letter];
        }
        } else
        { if(is.in(as.numeric(letter), dag$adj)==TRUE)
          # the above use of as.numeric() was required due to some strange behaviour:
          #  without it, in some cases, this block would be skipped despite letter
          #  being in dag$adj; for instance with demo.dag2, if C1,3,5,7, or 9 was
          #  adjusted, they would not appear so in the write.paths() output, whereas
          #  both the manual use of dag.letter() and the coding for the nodes in dag.draw
          #  would produce the correct barred/underlined output. however, other DAGs,
          #  e.g. demo.dag1, were not affected!
        { if( (alt.symb==FALSE) || (is.na(dag$symbols[letter])) ) 
        { paste0("_C", i_c);
        } else  
        { paste0("_", dag$symbols[letter]);
        }
        } else 
        { if( (alt.symb==FALSE) || (is.na(dag$symbols[letter])) ) 
        { paste0("C", i_c);
        } else
        { dag$symbols[letter];
        }
        }
        }
      }
  }