function b=isGrade(A,g)% isGrade(A,g): return 1 if A is of grade g%%See also gable.% GABLE, Copyright (c) 1999, University of Amsterdam% Copying, use and development for non-commercial purposes permitted.%          All rights for commercial use reserved; for more information%          contact Leo Dorst (leo@wins.uva.nl).%%          This software is unsupported.if g==0 | A==0	b = 1;elseif g==1 | g==2 | g==3 | g==-1	b = 0;else	error('isGrade: invalid grade.');end