refresh_index.m

function [ newindmin newindmax newindzer ] = refresh_index( x,indmin,indmax,indzer )
% Find the new indmin, indmax and inzer

%clear result
newindmin=[];
newindmax=[];
newindzer=[];

%find new indzer
for n=1:length(indzer)
    if x(indzer(n))~=0
        if indzer(n)==1
            newindzer(n)=indzer(n)-x(indzer(n))/(x(indzer(n)+1)-x(indzer(n)));
        elseif indzer(n)==length(x)
            newindzer(n)=indzer(n)-1-x(indzer(n)-1)/(x(indzer(n))-x(indzer(n)-1));
        else
            if x(indzer(n))*x(indzer(n)+1)<0
                newindzer(n)=indzer(n)-x(indzer(n))/(x(indzer(n)+1)-x(indzer(n)));
            elseif x(indzer(n))*x(indzer(n)-1)<0
                newindzer(n)=indzer(n)-1-x(indzer(n)-1)/(x(indzer(n))-x(indzer(n)-1));
            end
        end
    else
        newindzer(n)=indzer(n);
    end
end

%find new indmin
for n=1:length(indmin)
    B=[];
    y=[];
    if indmin(n)<4
        for scale=4-indmin(n):6
            B=[B;(indmin(n)-3+scale)^2 indmin(n)-3+scale 1];
            y=[y;x(indmin(n)-3+scale)];
        end
        a=((B'*B)\B')*y;
        newindmin(n)=-a(2)/(2*a(1));
    elseif indmin(n)>length(x)-3
        for scale=0:6-(indmin(n)-length(x)+3)
            B=[B;(indmin(n)-3+scale)^2 indmin(n)-3+scale 1];
            y=[y;x(indmin(n)-3+scale)];
        end
        a=((B'*B)\B')*y;
        newindmin(n)=-a(2)/(2*a(1));
    else
        for scale=0:6
            B=[B;(indmin(n)-3+scale)^2 indmin(n)-3+scale 1];
            y=[y;x(indmin(n)-3+scale)];
        end
        a=((B'*B)\B')*y;
        newindmin(n)=-a(2)/(2*a(1));
    end
end

%find new max
for n=1:length(indmax)
    B=[];
    y=[];
    if indmax(n)<4
        for scale=4-indmax(n):6
            B=[B;(indmax(n)-3+scale)^2 indmax(n)-3+scale 1];
            y=[y;x(indmax(n)-3+scale)];
        end
        a=((B'*B)\B')*y;
        newindmax(n)=-a(2)/(2*a(1));
    elseif indmax(n)>length(x)-3
        for scale=0:6-(indmax(n)-length(x)+3)
            B=[B;(indmax(n)-3+scale)^2 indmax(n)-3+scale 1];
            y=[y;x(indmax(n)-3+scale)];
        end
        a=((B'*B)\B')*y;
        newindmax(n)=-a(2)/(2*a(1));
    else
        for scale=0:6
            B=[B;(indmax(n)-3+scale)^2 indmax(n)-3+scale 1];
            y=[y;x(indmax(n)-3+scale)];
        end
        a=((B'*B)\B')*y;
        newindmax(n)=-a(2)/(2*a(1));
    end
end
end