Bug in ultraSEMSol.feval for quads

[nickhale]

Although the computed coefficients of the solution in the following match to machine precision, the evaluated solutions are very different (presumably with error in the evaluation of the quad version):

p = 60;
rhs = -1;

N = chebop2(@(u) lap(u)); N.bc = 0;
sol = N\rhs;

% Solve using rectangles
R = ultraSEMDomain.rectangle; 
S = ultraSEM(R, {1,0,0}, rhs, p);
sol1 = S\0;
figure
[xx, yy] = getGrid(sol1);
err = abs(feval(sol, xx, yy) - feval(sol1, xx, yy));
surf(xx, yy, log10(err));

% Solve using quads
R2 = ultraSEMDomain.quad([-1 -1; 1 -1 ; 1 1 ; -1 1]);
S = ultraSEM(R2, {1,0,0}, rhs, p);
sol2 = S\0;
figure
[xx, yy] = getGrid(sol1);
err = abs(feval(sol, xx, yy) - feval(sol2, xx, yy));
surf(xx, yy, log10(err));
alignfigs

err_coeffs = norm(sol2.u{1} - sol1.u{1}, inf)

[danfortunato]

Fixed in 00bf7652d114e6820281fda397913b79d0c4dc2c.