Mauch MIREX 2010

%

%NOTE2DEGREE convert a note to a degree w.r.t. a given root

% 

% [degree,success,errormessage] = note2degree(note,root,{octave},{verbose})

% 

% Converts a note string to a degree with respect to a given root note.

% Optional value octave gives octave offset to account for extended

% intervals.

% 

% Success = 1 if note converted correctly, 0 otherwise.

% 

% Optional argument octave defaults to 0.  

% 

% If optional argument 'verbose' is 1, function prints any errormessage to 

% the screen.

% 

% calls: note2fifthposition

%

% returns:  degree (string)

%           success (boolean)

%           errormessage (string)

% 

%

% Author: Christopher Harte,  September 2005

% 

% Copyright: Centre for Digital Music, Queen Mary University of London 2005 

%

% This file is part of the C4DM Chord Toolkit.  

%

% The C4DM Chord Toolkit is free software; you can redistribute it and/or 

% modify it under the terms of the GNU General Public License as published 

% by the Free Software Foundation; either version 2 of the License, or

% (at your option) any later version.

%

% The C4DM Chord Toolkit is distributed in the hope that it will be useful,

% but WITHOUT ANY WARRANTY; without even the implied warranty of

% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

% GNU General Public License for more details.

%

% You should have received a copy of the GNU General Public License

% along with the C4DM Toolkit; if not, write to the Free Software

% Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

%		

function [degree,success,errormessage] = note2degree(note, root,octave, verbose)

% set verbose default to 0

if nargin < 3

   octave = 0; 

   verbose = 0;

elseif nargin < 4

   verbose = 0;

end

errormessage = '';

success = 1;

degree = '';

% interval translations on the line of fifths

fifthtranslations = [1,5,2,6,3,7,4];

% get note and root natural position and accidentals on line of fifths 

[noteposition, success1,error1] = note2fifthposition(note);

[rootposition, success2,error2] = note2fifthposition(root);

if success1 && success2

    % take the difference between the two note positions for relative positions

    % of notes with respect to one and other

    fifthsdifference = noteposition - rootposition + 1;

    % natural difference on line of fifths

    fifthsinterval = mod((fifthsdifference-1),7);

    i=0;

    % find number of accidentals apart on line of fifths

    if fifthsdifference < 0 % if above 0 then either natural or sharp

      %if final position is negative then calculate number of flats

        % remembering to include the extra first flat (-1)

        accidentals = fix((fifthsdifference+1)/7) -1;

    else

        % note is a natural or has a number of sharps

        accidentals = fix(fifthsdifference/7);

    end

    % put the required number of sharps or flats into the output string

    if accidentals > 0

        for i=1:accidentals

           degree = ['#' degree];

        end

    elseif accidentals <=0

        for i=1:abs(accidentals)

           degree = ['b' degree];

        end

    end    

    % find interval value from translation array

    interval = fifthtranslations(fifthsinterval+1);

    if octave >= 0

        interval = interval + 7.*octave;

    else

        success = 0;

        errormessage = 'Error in note2degree: Octave argument is negative';

    end

    degree = [degree num2str(interval)];

else

    success = 0;

    errormessage = [error1 error2];

end

if (success == 0) && (verbose == 1)   

    fprintf(1,errormessage);

end