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boolean computation - Discrete Measure between Binary Vectors



I would like a discrete distance measure between two binary vectors (or strings). Like HammingDistance but I want the vectors to be considered closer if they have more matches that are separated by zeros (or a default value).


For example: given the four vectors and distance measure thedistancemeasure


           vec1={1,0,0,0,0,1,0,1};
vec2={1,0,1,0,0,1,0,0};

vec3={1,0,0,0,1,1,0,0};
vec4={0,1,0,0,1,1,0,0};

such that.


  thedistancemeasure[vec1,vec2]< thedistancemeasure[vec3,vec4]



True



The measure likes small group of matches that are well separated versus a large group of matches that are "connected" or less seperated.


The amount of zeros shouldn't matter, but if it does, I prefers more zeros to give a smaller measure. The more separated the better.


If possible I also want the measure to give even closer distances for higher count of well separated correctly matched ones, for example.


            vec5={1,0,0,1,0,1,0,1};
vec6={1,0,0,1,0,0,0,1};


would give.


 thedistancemeasure[vec1,vec2]>thedistancemeasure[vec5,vec6]


True



The size of the vectors would always be fixed.


It might be possible using the output from ListCorrelate since it should give the position correlations between lists.



Answer



ClearAll[distF1, distF2]

distF1 = With[{p = Intersection @@ (Flatten@ SparseArray[#]["NonzeroPositions"]&/@ #)},
-Length @ p] &;
distF2 = With[{p = Intersection @@ (Flatten@SparseArray[#]["NonzeroPositions"]&/@#)},
-Total[Differences@p]] &;

Example:


vec1 = {1, 0, 0, 0, 0, 1, 0, 1};
vec2 = {1, 0, 1, 0, 0, 1, 0, 0};
vec3 = {1, 0, 0, 0, 1, 1, 0, 0};
vec4 = {0, 1, 0, 0, 1, 1, 0, 0};

vec5 = {1, 0, 0, 1, 0, 1, 0, 1};
vec6 = {1, 0, 0, 1, 0, 0, 0, 1};
vecs = {vec1, vec2, vec3, vec4, vec5, vec6};
pairs = Partition[vecs, 2];
plabels = {"v1v2", "v3v4", "v5v6"};

Sort pairs lexicographically in ascending order using the distance function distF1 and breaking ties with the distance function distF2:


SortBy[pairs, {distF1, distF2}] /. Thread[pairs -> plabels]
{"v5v6", "v1v2", "v3v4"}

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