view findZeros.m @ 1198:2924b3a9b921 feature/d2_compatible

Add OpSet for fully compatible D2Variable, created from regular D2Variable by replacing d1 by first row of D1. Formal reduction by one order of accuracy at the boundary point.
author Martin Almquist <malmquist@stanford.edu>
date Fri, 16 Aug 2019 14:30:28 -0700
parents 8368beb0d1b3
children
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% findZeros looks for solutions to the equation f(x)==0 within
% the limits lim with a granularity of h.
% Returns a sorted list of unique solutions.
function z = findZeros(f, lim, h)
    n = ceil((lim(2)-lim(1))/h);
    z0 = linspace(lim(1), lim(2), n);

    z = zeros(1,n);

    for i = 1:n
        zt(i) = fzero(f, z0(i));
    end

    zt = sort(zt);

    z = [];
    for i = 1:n
        if zt(i)  < lim(1) || zt(i) > lim(2)
            continue
        end

        if ~isempty(z) && abs(z(end) - zt(i)) < 1e-6
            continue
        end

        z = [z zt(i)];
    end

    % z = unique(z);
end