function res = ctranspose(obj,useconj);

    if nargin == 1

        useconj = 1;

    end

    if length(obj.dimensions) > 2

        error('Cannot transpose array');

    end

    % make new memory mapped data file

    % --------------------------------

    newFileName = mmo.getnewfilename;

    copyfile(obj.dataFile, newFileName);

    res = obj;

    res.dimensions = [ obj.dimensions(2) obj.dimensions(1) ];

    res.dataFile = newFileName;

    tmpMMO1 = memmapfile(obj.dataFile, 'writable', obj.writable, 'format', { 'single' obj.dimensions 'x' });

    tmpMMO2 = memmapfile(res.dataFile, 'writable',         true, 'format', { 'single' res.dimensions 'x' });

    % copy the data

    % -------------

    if length(obj.dimensions) == 1 || obj.dimensions(1) > obj.dimensions(2)

        for index = 1:size(obj,2)

            s.type = '()';

            s.subs = { ':' index };

            if useconj, tmpMMO2.Data.x(index,:) = conj(subsref(tmpMMO1.Data.x,s));

            else        tmpMMO2.Data.x(:,index) =      subsref(tmpMMO1.Data.x,s);

            end

        end

    else

        for index = 1:size(obj,1)

            s.type = '()';

            s.subs = { index ':' };

            if useconj, tmpMMO2.Data.x(:,index) = conj(subsref(tmpMMO1.Data.x,s));

            else        tmpMMO2.Data.x(:,index) =      subsref(tmpMMO1.Data.x,s);

            end

        end

    end