## Copyright (C) 2024 David Legland
## All rights reserved.
## 
## Redistribution and use in source and binary forms, with or without
## modification, are permitted provided that the following conditions are met:
## 
##     1 Redistributions of source code must retain the above copyright notice,
##       this list of conditions and the following disclaimer.
##     2 Redistributions in binary form must reproduce the above copyright
##       notice, this list of conditions and the following disclaimer in the
##       documentation and/or other materials provided with the distribution.
## 
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ''AS IS''
## AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
## IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
## ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
## ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
## DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
## SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
## CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
## OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
## 
## The views and conclusions contained in the software and documentation are
## those of the authors and should not be interpreted as representing official
## policies, either expressed or implied, of the copyright holders.

function [nodes2, edges2] = grRemoveEdges(nodes, edges, rmEdges)
%GRREMOVEEDGES Remove several edges from a graph.
%
%   [NODES2 EDGES2] = grRemoveEdges(NODES, EDGES, EDGES2REMOVE)
%   Remove some edges in the edges list, and return the modified graph.
%   The NODES array is not modified.

% ------
% Author: David Legland 
% E-mail: david.legland@inrae.fr
% Created: 2003-08-13
% Copyright 2003-2023 INRA - TPV URPOI - BIA IMASTE

rmEdges = sort(rmEdges);

% do not change the node list
nodes2 = nodes;

% number of edges
N   = size(edges, 1);
NR  = length(rmEdges);
N2  = N - NR;

% allocate memory for new  edges list
edges2 = zeros(N2, 2);

% case of no edge to remove
if NR == 0
    nodes2 = nodes;
    edges2 = edges;
    return;
end

% process the first edge
edges2(1:rmEdges(1)-1,:) = edges(1:rmEdges(1)-1,:);

% process the classical edges
for i = 2:NR
    %if rmEdges(i)-i < rmEdges(i-1)-i+2 
    %    continue;
    %end
    edges2(rmEdges(i-1)-i+2:rmEdges(i)-i, :) = edges(rmEdges(i-1)+1:rmEdges(i)-1, :);
end

% process the last edge
edges2(rmEdges(NR)-NR+1:N2, :) = edges(rmEdges(NR)+1:N, :);
