subsasgn.m

几个关于多小波的程序

function Pi = subsasgn(P,S,B)

% SUBSASGN -- assignment to subscripted matrix polynomial
% 
% This function is not meant to be called by the user. It is called by
% Matlab when a subscripted matrix polynomial appears on the
% left-hand side of an operation.
%
% The only allowed operations are
%
%        P.min  = Pmin            change starting exponent
%        P.coef = C               change coefficients
%        P.type = 'type'          change type
%        P.m    = m               change dilation factor
%        P.r    = r               change multiplicity
%
%        P{i}   = matrix          Change an individual coefficient matrix
%                                 An assignment with index outside
%                                 existing limits is allowed, and
%                                 increases the size of P.
%
%        P(submatrix) = M         insert matrix polynomial as submatrix
%                                 An assignment with index outside
%                                 existing limits is allowed, and
%                                 increases the size of P.

% Copyright (c) 2004 by Fritz Keinert ([e-mail]),
% Dept. of Mathematics, Iowa State University, Ames, IA 50011.
% This software may be freely used and distributed for non-commercial
% purposes, provided this copyright statement is preserved, and
% appropriate credit for its use is given.
%
% Last update: Feb 20, 2004

switch S.type
    
 case '.' % reset min, coef, type, m, r
  Pi = set(P,S.subs,B);
  
 case '()' % insert matrix polynomial as submatrix
  if (isnumeric(P) & ~isnumeric(B))
      P = sym(P);
  end

% determine starting/ending subscripts of result
  if ~isa(B,'mpoly')
      B = mpoly(B);
  end

  Pimin = min(P.min,B.min);
  Pimax = max(get(P,'max'),get(B,'max'));
  Pi = trim(P,[Pimin,Pimax]);
  B  = trim(B,[Pimin,Pimax]);
  Pi.coef(S.subs{:},:) = B.coef;
  Pi = trim(Pi);
  
 case '{}' % change one coefficient
  if (length(S.subs) > 1)
      error('left-hand side subscript must be a single integer');
  end
  index = S.subs{1};
  if (length(index) ~= 1 | index ~= round(index))
      error('left-hand side subscript must be a single integer');
  end	
  Pmax = get(P,'max');
  Pi = P;
  if (index > Pmax) % add coefficient beyond last one
      Pi.coef = cat(3,Pi.coef,zeros(size(Pi.coef,1),size(Pi.coef,2),index-Pmax-1),B);
  elseif (index < P.min) % add coefficient before first one
      Pi.coef = cat(3,B,zeros(size(Pi.coef,1),size(Pi.coef,2),P.min-index-1),Pi.coef);
      Pi.min = index;
  else % replace existing coefficient
      Pi.coef(:,:,index - Pi.min + 1) = B;
  end
  Pi = trim(Pi);
 otherwise
  error('this should not happen')
end