christopherh@1: %
christopherh@1: %NOTE2INTERVAL convert a note to an interval w.r.t. a given root
christopherh@1: % 
christopherh@1: % [interval,success,errormessage] = note2interval(note,root,{octave},{verbose})
christopherh@1: % 
christopherh@1: % Converts a note string to an interval with respect to a given root note.
christopherh@1: % Optional value octave gives octave offset to account for extended
christopherh@1: % degrees.
christopherh@1: % 
christopherh@1: % Success = 1 if note converted correctly, 0 otherwise.
christopherh@1: % 
christopherh@1: % Optional argument octave defaults to 0.  
christopherh@1: % 
christopherh@1: % If optional argument 'verbose' is 1, function prints any errormessage to 
christopherh@1: % the screen.
christopherh@1: % 
christopherh@1: % calls: note2fifthposition
christopherh@1: %
christopherh@1: % returns:  interval (string)
christopherh@1: %           success (boolean)
christopherh@1: %           errormessage (string)
christopherh@1: % 
christopherh@1: %
christopherh@1: % Author: Christopher Harte,  March 2009
christopherh@1: % 
christopherh@1: % Copyright: Centre for Digital Music, Queen Mary University of London 2005 
christopherh@1: %
christopherh@1: % This file is part of the C4DM Chord Toolkit V2.0  
christopherh@1: %
christopherh@1: % The C4DM Chord Toolkit is free software; you can redistribute it and/or 
christopherh@1: % modify it under the terms of the GNU General Public License as published 
christopherh@1: % by the Free Software Foundation; either version 2 of the License, or
christopherh@1: % (at your option) any later version.
christopherh@1: %
christopherh@1: % The C4DM Chord Toolkit is distributed in the hope that it will be useful,
christopherh@1: % but WITHOUT ANY WARRANTY; without even the implied warranty of
christopherh@1: % MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
christopherh@1: % GNU General Public License for more details.
christopherh@1: %
christopherh@1: % You should have received a copy of the GNU General Public License
christopherh@1: % along with the C4DM Toolkit; if not, write to the Free Software
christopherh@1: % Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
christopherh@1: 
christopherh@1: %		
christopherh@1: function [interval,success,errormessage] = note2interval(note, root,octave, verbose)
christopherh@1: 
christopherh@1: % set verbose default to 0
christopherh@1: if nargin < 3
christopherh@1:    octave = 0; 
christopherh@1:    verbose = 0;
christopherh@1: 
christopherh@1: elseif nargin < 4
christopherh@1:    verbose = 0;
christopherh@1: end
christopherh@1: 
christopherh@1: errormessage = '';
christopherh@1: success = 1;
christopherh@1: interval = '';
christopherh@1: 
christopherh@1: % degree translations on the line of fifths
christopherh@1: fifthtranslations = [1,5,2,6,3,7,4];
christopherh@1: 
christopherh@1: 
christopherh@1: % get note and root natural position and accidentals on line of fifths 
christopherh@1: [noteposition, success1,error1] = note2fifthposition(note);
christopherh@1:   
christopherh@1: [rootposition, success2,error2] = note2fifthposition(root);
christopherh@1: 
christopherh@1: if success1 && success2
christopherh@1: 
christopherh@1:     % take the difference between the two note positions for relative positions
christopherh@1:     % of notes with respect to one and other
christopherh@1:     fifthsdifference = noteposition - rootposition + 1;
christopherh@1: 
christopherh@1:     % natural difference on line of fifths
christopherh@1:     fifthsdegree = mod((fifthsdifference-1),7);
christopherh@1: 
christopherh@1:     i=0;
christopherh@1: 
christopherh@1:     % find number of accidentals apart on line of fifths
christopherh@1:     if fifthsdifference < 0 % if above 0 then either natural or sharp
christopherh@1: 
christopherh@1:       %if final position is negative then calculate number of flats
christopherh@1:         % remembering to include the extra first flat (-1)
christopherh@1:         accidentals = fix((fifthsdifference+1)/7) -1;
christopherh@1:     
christopherh@1:     else
christopherh@1:         % note is a natural or has a number of sharps
christopherh@1:         accidentals = fix(fifthsdifference/7);
christopherh@1: 
christopherh@1:     end
christopherh@1: 
christopherh@1: 
christopherh@1:     % put the required number of sharps or flats into the output string
christopherh@1:     if accidentals > 0
christopherh@1:         
christopherh@1:         for i=1:accidentals
christopherh@1:             
christopherh@1:            interval = ['#' interval];
christopherh@1:             
christopherh@1:         end
christopherh@1:         
christopherh@1:     elseif accidentals <=0
christopherh@1:         
christopherh@1:         for i=1:abs(accidentals)
christopherh@1:             
christopherh@1:            interval = ['b' interval];
christopherh@1:             
christopherh@1:         end
christopherh@1:     end    
christopherh@1:     
christopherh@1:     
christopherh@1:     % find degree value from translation array
christopherh@1:     degree = fifthtranslations(fifthsdegree+1);
christopherh@1: 
christopherh@1:     if octave >= 0
christopherh@1:         degree = degree + 7.*octave;
christopherh@1:     else
christopherh@1:         success = 0;
christopherh@1:         errormessage = 'Error in note2interval: Octave argument is negative';
christopherh@1:     end
christopherh@1: 
christopherh@1: 
christopherh@1: 
christopherh@1:     interval = [interval num2str(degree)];
christopherh@1: 
christopherh@1: else
christopherh@1:     success = 0;
christopherh@1:     errormessage = [error1 error2];
christopherh@1: end
christopherh@1:     
christopherh@1: if (success == 0) && (verbose == 1)   
christopherh@1:     fprintf(1,errormessage);
christopherh@1: end  
christopherh@1: 
christopherh@1: