Method on @infsup: X = mulrev (B, C, X)
Method on @infsup: X = mulrev (B, C)
Method on @infsup: [U, V] = mulrev (B, C)
Method on @infsup: [U, V] = mulrev (B, C, X)

Compute the reverse multiplication function or the two-output division.

That is, an enclosure of all x ∈ X where x .* b ∈ C for any b ∈ B.

This function is similar to interval division C ./ B. However, it treats the case 0/0 as “any real number” instead of “undefined”.

Interval division, considered as a set, can have zero, one or two disjoint connected components as a result. If called with two output parameters, this function returns the components separately. U contains the negative or unique component, whereas V contains the positive component in cases with two components.

Accuracy: The result is a tight enclosure.

c = infsup (1);
b = infsup (-inf, inf);
[u, v] = mulrev (b, c)
  ⇒
    u = [-inf, 0]
    v = [0, inf]

See also: @infsup/times.

Package: interval