oldeq.m

function [max_M,BMD] = calc_BMD(left_sup, right_sup, loading, cur_pos, list_x)
    % get SFD from given parameters; max shear is irrelevant here
    [irrelevant, SFD]=calcSFD(left_sup, right_sup, loading, cur_pos, list_x);
    % integrates SFD using trapezoid approx.
    BMD=cumtrapz(SFD);
    % create absolute value of BMD to find max moment
    abs_BMD = abs(BMD);
    max_M = max(abs_BMD);
end

function [max_V,SFD] = calc_SFD(left_sup, right_sup, loading, pos_list, list_x)
    % set entire SFD to left_sup force
    SFD = ones(1,length(list_x)).*left_sup;
    % keeping track of current values
    max_V = left_sup;
    cur_V = left_sup;
    load_num = 1;
    % iterate through the positions of loading
    for cur_pos = pos_list
        % changes current shear from corresponding value in load list
        cur_V = cur_V-loading(load_num);
        % updates so next load is applied
        load_num = load_num + 1;
        % changes all SFD values after current position to new shear
        SFD(cur_pos+1:length(SFD)) = cur_V; 
        % +1 to account for the zero; x=1200 has position of 1201 in vector
        % checks for new max shear
        if abs(cur_V) > abs(max_V)
            max_V = cur_V;
        end
    end
    % finishes SFD with the right support
    SFD(length(SFD)) = SFD(length(SFD))+right_sup;
end