assert_winready.m

linear time－frequency toolbox

function [winpos,L]=assert_winready(self,Lin,thisw,dofac,evalother,callfun)
%ASSERT_WINREADY   Make sure that a window is ready for calculation.
%   Usage:  [winpos,L]=assert_winready(self,Lin,thisw,dofac,evalother,callfun);
%
%   Input parameters:
%       self      : Number of tfr object to use.
%       L         : Length of transform.
%       thisw     : Window to consider.
%       dofac     : Compute factorization?
%       evalother : Are we evaluating the other window?
%       callfun   : Name of calling function.
%   Output parameters:
%       winpos    : Position of window to use
%       L         : Transform length.
%       
%   winpos is normally equal to thisw, but might change if a tight
%   window is being used.
%
%   evalother is used for explicitly evaluating the other window, in
%   the case that it is needed, i.e. for candual, cantight etc. thisw
%   must point to the other window, but istight will be ignored

% The window can be speficied in several categories:
%
% 1) A previously determined FIR window.
% 2) A not yet determined FIR window.
% 3) A previously determined IIR window.
% 4) A not yeat determined IIR window.
%
% We shall refer to the cases below.

global TF_STORAGE;

% Determine which window is requested, and which is the other window.
% This changes if we are using a tight window.
istight=TF_STORAGE.data{self}.istight;
if (istight>0) && (~evalother)
  thisw=istight;
  otherw=3-thisw;
else
  otherw=3-thisw;
end;
winpos=thisw;

wininfo=TF_STORAGE.data{self}.w{thisw};

% Quick references.
a=TF_STORAGE.data{self}.a;
M=TF_STORAGE.data{self}.M;

% Make sure the other window has been evaluated, if it is needed for
% the calculation of this window.
if wininfo.otherdepend
  assert_winready(self,Lin,otherw,0,1,callfun);
  gother=TF_STORAGE.data{self}.w{otherw}.g;
  
end;

if wininfo.Lwin>0
  % Handle case 1 and case 3.

  % The window is an already calculated FIR window. Determine L and
  % return as quickly as possible.
  [b_junk,N_junk,L]=assert_L(Lin,wininfo.Lwin,a,M,callfun);
    
else

  % Handle case 2 and case 4.
  
  % Now we can determine L, since there is no fixed window size to respect.
  % We simple use the signal length as the window length to avoid trouble.
  [b_junk,N_junk,L]=assert_L(Lin,0,a,M,callfun);
  
end;

% Determine and make quick references to the DGT information.
dgtinfo=TF_STORAGE.data{self}.dgtinfo;
L_dgt=L*dgtinfo.Lmul;
a_dgt=dgtinfo.a;
M_dgt=dgtinfo.M;

% Case 2 and 4.
if wininfo.Lwin<=0 
  % Choose a whole point even centering unless a half-point even centering
  % is explicitly requested.
  centering=0;
  if dgtinfo.iseven==2
    centering=.5;
  end;
  
  % The window has not yet been evaluated, or it has been evaluated to
  % an incorrect size.
  if (wininfo.Lwin==0) || (wininfo.Lwin<0 && wininfo.Lwin~=-L); 
    
    switch wininfo.name
      case 'none'
	error([callfun,': No window specified.']);
      case {'pgauss','psech','gauss','sech'}
	% Determine which of the parameters have been explicitly specified
	% and which ones should be handled now.
	if isempty(wininfo.funpars{1})
	  tfr=a_dgt*M_dgt/L_dgt;
	else
	  tfr=wininfo.funpars{1};
	end;
	if isempty(wininfo.funpars{2})
	  centering=0;
	  if dgtinfo.iseven==2
	    centering=0.5;
	  end;
	else
	  centering=wininfo.funpars{2};
	end;
		   
	switch wininfo.name
	  case {'pgauss','gauss'}
	    g=comp_pgauss(L_dgt,tfr,centering);
	  case {'psech','sech'}
	    g=psech(L_dgt,tfr,centering);
	end;
	Lwin=-L;
      case 'phanning'
	error('NOT DONE YET');
      case 'candual'
	g=candual(gother,a_dgt,M_dgt);
	g=dgtinfo.winscale*g;
	Lwin=-L;
      case 'cantight'
	g=cantight(gother,a_dgt,M_dgt);
	g=sqrt(dgtinfo.winscale)*g;
	Lwin=-L;
      case 'pherm'
	switch length(wininfo.funpars)
	  case 1
	    g=pherm(L_dgt,wininfo.funpars{1},a_dgt*M_dgt/L_dgt);
	  case 2
	    g=pherm(L_dgt,wininfo.funpars{1},wininfo.funpars{2});
	  case 3
	    % XXX missing support for centering.
	    error('NOT DONE YET');
	  otherwise
	    length(wininfo.funpars)
	    wininfo.funpars
	    error('IMPOSSIBLE');
	end;	
	Lwin=-L;
      case 'pbspline'
	error('NOT DONE YET');
      case 'phanning'
	error('NOT DONE YET');
      case 'firdual'
	error('NOT DONE YET');
      case 'firtight'      
	error('NOT DONE YET');
    end;
    
    g_dgt=g;
    % Shift the window if requested.
    if (dgtinfo.c_w>0)
      g_dgt=circshift(g,dgtinfo.c_w);
    end;
  
    % Set the window and the size.
    TF_STORAGE.data{self}.w{thisw}.g=g;
    TF_STORAGE.data{self}.w{thisw}.g_dgt=g_dgt;
    TF_STORAGE.data{self}.w{thisw}.Lwin=Lwin;
    TF_STORAGE.data{self}.w{thisw}.hasfac=0;
    
    % Reinitialize winfo, this might be needed two lines below:
    wininfo=TF_STORAGE.data{self}.w{thisw};
  end;

end;

% Calculate factorization if needed and if it has not yet been done.
if ((dofac) && (abs(wininfo.Lwin)==L) && (wininfo.hasfac==0))
  TF_STORAGE.data{self}.w{thisw}.gf=comp_wfac(TF_STORAGE.data{self}.w{thisw}.g_dgt,a_dgt,M_dgt);
  TF_STORAGE.data{self}.w{thisw}.hasfac=1;
end;