[Octave-bug-tracker] [bug #40105] Logical diagonal matrices are not supported

[David Spies]

Follow-up Comment #3, bug #40105 (project octave):

Logical matrix multiplication comes up quite a lot.  Of course, I could just
convert to a matrix of doubles, but that would be a workaround.

As an example, suppose I have a logical matrix A where each row represents a
set (and all sets are unique).  Now suppose I want to remove any set which is
a subset of another row (such as when finding all maximal cliques in an
undirected graph).

cardinality = sum(A,2);
coincidence = A * A'; %Logical matrix multiplication
subsets = any(coincidence == cardinality, 2); % Using automatic broadcasting
with ==
A = A(~subsets,:);

As an example of where logical diagonal matrix multiplication comes in handy,
suppose I want to mux the rows from matrices A and B according to a logical
column vector s

res = (diag(~s) * A) | (diag(s) * B);


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