--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/m-toolbox/classes/@parfrac/fromRational.m	Wed Nov 23 19:22:13 2011 +0100
@@ -0,0 +1,73 @@
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+%
+% FUNCTION:    fromRational
+%
+% DESCRIPTION: Construct a parfrac from a rational TF
+%
+% CALL:        pf = fromRational(a, pl)
+%
+% PARAMETER:   pl - plist
+%
+%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
+function pf = fromRational(pf, pli)
+  
+  VERSION = '$Id: fromRational.m,v 1.12 2011/08/15 12:31:59 hewitson Exp $';
+  
+  
+  % get pzmodel info
+  ii = parfrac.getInfo('parfrac', 'From Rational');
+  
+  % Set the method version string in the minfo object
+  ii.setMversion([VERSION '-->' ii.mversion]);
+  
+  % Combine input plist with default values
+  pl = applyDefaults(ii.plists, pli);
+  
+  % Set fields
+  rat      = find(pl, 'rational');
+  
+  % if the denominator is not a polynomial but a single number, then the
+  % model is not really a rational model. It is practically a polynomial
+  % model and cannot be converted in partial fractions. Output PF model
+  % will be a zero residues and poles. Dterms will contain the numerator
+  % polynomial
+  if numel(rat.den)==1
+    pf.res = 0;
+    pf.poles = 0;
+    pf.dir = (rat.num)./(rat.den);
+    pf.pmul = 0;
+  else % convert a true rational model in partial fractions
+    [res, poles, dterms, pmul] = utils.math.cpf('INOPT', 'RAT', ...
+      'NUM', rat.num, ...
+      'DEN', rat.den, 'MODE', 'SYM');
+    
+    pf.res = res;
+    pf.poles = poles;
+    pf.dir = dterms;
+    pf.pmul = pmul;
+  end
+  
+  % Set properties from rational object
+  if isempty(pl.find('ounits'))
+    pl.pset('ounits', rat.ounits);
+  end
+  
+  if isempty(pl.find('iunits'))
+    pl.pset('iunits', rat.iunits);
+  end
+  
+  if isempty(pl.find('name'))
+    pl.pset('name', sprintf('parfrac(%s)', rat.name));
+  end
+  
+  if isempty(pl.find('description'))
+    pl.pset('description', rat.description);
+  end
+  
+  % Add history
+  pf.addHistory(ii, pl, [], rat.hist);
+  
+  % Set object properties
+  pf.setObjectProperties(pl);
+  
+end