reduceHrep

 reduce a H-representation to non-redundant support hyperplanes

 Syntax: hrep = reduceVrep(hrep)

 This function wraps a cddlib function that reduces a set of inequalities
   to a non-redundant set.

 Scaling of the input is important, because cddlib applies a fixed zero 
   tolerance. This tolerance is stored in the function zerotolCddlib 
   during initialization of this library (buildCddlib).

 See also: convertPolytope

• callCddLib ==========================================================================
• scaleHrep scale polytope to reasonable size and position

• fixPositionAndGetOriginHoughHealpix fix the position and get the origin to get the symmetric h representation
• fixPositionAndGetOriginHoughHealpixAggregate fix the position and get the origin for a primary particle of an aggregate
• computeCollectiveShapeStruct compute information to quickly operate on lambda-shapes
• addFacetValidityData add data to identify invalid facets
• appendPartitionDataForEmbedding append embedding (unified) partition data
• computeIntersectionHrep compute the intersection of two polytopes in H-representation
• computeMeanWidthHrep compute the mean width of a polytope in H-representation

0001 function hrep = reduceHrep(hrep, zerotol)
0002 % reduce a H-representation to non-redundant support hyperplanes
0003 %
0004 % Syntax: hrep = reduceVrep(hrep)
0005 %
0006 % This function wraps a cddlib function that reduces a set of inequalities
0007 %   to a non-redundant set.
0008 %
0009 % Scaling of the input is important, because cddlib applies a fixed zero
0010 %   tolerance. This tolerance is stored in the function zerotolCddlib
0011 %   during initialization of this library (buildCddlib).
0012 %
0013 % See also: convertPolytope
0014 
0015 % The elk-library: convex geometry applied to crystallization modeling.
0016 %   Copyright (C) 2012 Alexander Reinhold
0017 %
0018 % This program is free software: you can redistribute it and/or modify it
0019 %   under the terms of the GNU General Public License as published by the
0020 %   Free Software Foundation, either version 3 of the License, or (at your
0021 %   option) any later version.
0022 %
0023 % This program is distributed in the hope that it will be useful, but
0024 %   WITHOUT ANY WARRANTY; without even the implied warranty of
0025 %   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
0026 %   General Public License for more details.
0027 %
0028 % You should have received a copy of the GNU General Public License along
0029 %   with this program.  If not, see <http://www.gnu.org/licenses/>.
0030 
0031 if isempty(hrep.A)
0032     return
0033 end
0034 
0035 %! Todo: Zerotol added for empty-polytope handling which must be considered
0036 %    in corresponding calls.
0037 if ~exist('zerotol', 'var') || isempty(zerotol)
0038     zerotol = elkZerotol;
0039 end
0040 
0041 %% handle empty polytopes
0042 % these are unfortunately not handled properly by cddlib
0043 [hrepScaled, scale] = scaleHrep(hrep, zerotol);
0044 if scale == -inf
0045     hrep = [];
0046     return;
0047 end
0048 
0049 hrep = callCddLib('reduce_h', struct('A', hrep.A, 'B', hrep.h));
0050 
0051 hrep = struct('A', hrep.A, 'h', hrep.B);