adapt1.m

自适应数值积分算法

function [SRmat,quad,err] = adapt1(f,a,b,tol)
SRmat = zeros(30,5);
iterating = 0;
done = 1;
SRvec = zeros(1,5);
SRvec = srule1(f,a,b,tol);
SRmat(1,1:5) = SRvec;
m = 1;
state = iterating;
while (state == iterating )
    n = m;
    for j = n : -1 : 1
        p = j;
        SR0vec = SRmat(p,:);
        err = SR0vec(4);
        tol = SR0vec(5);
        if (tol <= err)
            state = done;
            SR1vec = SR0vec;
            SR2vec = SR0vec;
            a = SR0vec(1);
            b = SR0vec(2);
            c = (a + b)/2;
            err = SR0vec(4);
            tol=SR0vec(5);
            tol2 = tol/2;
            SR1vec = srule1(f,a,c,tol2);
            SR2vec = srule1(f,c,b,tol2);
            err = abs(SR0vec(3) - SR1vec(3) - SR2vec(3))/10;
            if (tol > err)
                SRmat(p,:) = SR0vec;
                SRmat(p,3) = SR1vec(3) + SR2vec(3);
                SRmat(p,4) = err;
            else
                SRmat( p + 1 : m + 1,: ) = SRmat( p : m, : );
                m = m + 1;
                SRmat(p,:) = SR1vec;
                SRmat(p + 1,:) = SR2vec;
                state = iterating;
            end
        end
    end
end
quad = sum(SRmat(:,3))
err = sum(abs(SRmat(:,4)))
SRmat = SRmat(1:m,1:5);