summaryrefslogtreecommitdiff
path: root/modules/elementary_functions/macros/intersect.sci
blob: 1e3d00348e7b03f33ae7b14730ddeec493d1f5ae (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
// Scilab ( http://www.scilab.org/ ) - This file is part of Scilab
// Copyright (C) INRIA - Serge Steer
// Copyright (C) DIGITEO - 2011 - Allan CORNET
//
// This file must be used under the terms of the CeCILL.
// This source file is licensed as described in the file COPYING, which
// you should have received as part of this distribution.  The terms
// are also available at
// http://www.cecill.info/licences/Licence_CeCILL_V2.1-en.txt

function [x_out, ka_out, kb_out] = intersect(a_in, b_in, orient)
    // returns the vector of common values of two vectors

    rhs = argn(2);
    if rhs < 2 then
        error(msprintf(gettext("%s: Wrong number of input argument(s): %d expected.\n"), "intersect", 2));
    end

    if ( (a_in == [])| (b_in == []) ) then
        x_out = [];
        ka_out = [];
        kb_out = [];
        return
    end
    if argn(2)<3 then
        //remove duplicate values in a_in and b_in
        [a, ka] = unique(matrix(a_in, 1, -1));
        [b, kb] = unique(matrix(b_in, 1, -1));
        kab = [ka, -kb];
        //find duplicated values in [a_in,b_in],
        [x,ksort] = gsort([a, b], "g", "i"); //sort the array

        kab = kab(ksort); //apply [a_in,b_in] sorting permutation to kab
        keq = find( x(2:$) == x(1:$-1) ); // find consecutive equal values index

        if keq == [] then
            //the intersection is empty
            x_out = [];
            ka_out = [];
            kb_out = [];
        else
            x_out = x(keq); //the intersection values in increasing order
            if argn(1) > 1 then //build the output index
                // each duplicated value appear twice  and only twice and in
                // consecutive positions keq(i) and keq(i)+1 in the sorted array x
                kab = kab([keq keq+1]);

                //the positive values correspond to a_in index while the negative to b_in index.
                ka_out = kab(kab > 0); //select index of intersection elements in a_in
                kb_out = -kab(kab < 0); //select index of intersection elements in b_in

                //insure that a_in(ka_out)==x_out and b_in(kb_out)==x_out.
                //I was'nt able to find a simple way.
                [s, k] = gsort(a_in(ka_out), "g", "i");
                ka_out = ka_out(k);
                [s, k] = gsort(b_in(kb_out),"g","i");
                kb_out = kb_out(k);
            end
        end
    elseif  orient==1|orient=="r" then
        //remove duplicate rows in a_in and b_in
        [a, ka] = unique(a_in, "r");
        [b, kb] = unique(b_in, "r");
        kab = [ka; -kb];
        //find duplicated rows in [a_in;b_in],

        [x,ksort] = gsort([a; b], "lr", "i"); //sort the rows

        kab = kab(ksort);//apply [a_in,b_in] sorting permutation to kab
        keq = find(and(x(2:$,:) == x(1:$-1,:),"c")) // find index of consecutive equal values

        if keq == [] then
            //the intersection is empty
            x_out = [];
            ka_out = [];
            kb_out = [];
        else
            x_out = x(keq,:); //the intersection values in increasing order

            if argn(1)>1 then //build the output index

                // each duplicated value appear twice  and only twice and in
                // consecutive positions keq(i) and keq(i)+1 in the sorted array x
                kab = kab([keq keq+1]);

                //the positive values correspond to a_in index while the negative to b_in index.
                ka_out = kab(kab>0); //select index of intersection elements in a_in
                kb_out = -kab(kab<0); //select index of intersection elements in b_in

                //insure that a_in(ka_out,:)==x_out and b_in(kb_out,:)==x_out.
                //I was'nt able to find a simple way.
                [s,k]=gsort(a_in(ka_out,:),"lr","i"); ka_out=ka_out(k)
                [s,k]=gsort(b_in(kb_out,:),"lr","i"); kb_out=kb_out(k)


            end
        end
    elseif  orient==2|orient=="c" then
        //remove duplicate columns in a_in and b_in
        [a,ka]=unique(a_in,"c");

        [b,kb]=unique(b_in,"c");
        kab=[ka, -kb];
        //find duplicated rows in [a_in;b_in],
        [x,ksort] = gsort([a b],"lc","i"); //sort the rows

        kab = kab(ksort);//apply [a_in,b_in] sorting permutation to kab
        keq = find(and(x(:,2:$) == x(:,1:$-1),"r")) // find index of consecutive equal values

        if keq == [] then
            //the intersection is empty
            x_out = [];
            ka_out = [];
            kb_out = [];
        else
            x_out =x(:,keq); //the intersection values in increasing order

            if argn(1)>1 then //build the output index

                // each duplicated value appear twice  and only twice and in
                // consecutive positions keq(i) and keq(i)+1 in the sorted array x
                kab=kab([keq keq+1]);

                //the positive values correspond to a_in index while the negative to b_in index.
                ka_out = kab(kab>0); //select index of intersection elements in a_in
                kb_out = -kab(kab<0); //select index of intersection elements in b_in

                //insure that a_in(ka_out,:)==x_out and b_in(kb_out,:)==x_out.
                //I was'nt able to find a simple way.
                [s,k]=gsort(a_in(:,ka_out),"lc","i"); ka_out=ka_out(k)
                [s,k]=gsort(b_in(:,kb_out),"lc","i"); kb_out=kb_out(k)
            end
        end

    else
        error(msprintf(gettext("%s: Wrong value for input argument #%d: %d,''%s'',%d or ''%s'' expected\n"),"intersect",3,1,"r",2,"c"));
    end

endfunction