matlab - Octave error when trying to integrate: "integrand F must return a single, real-valued vector of the same size as the input" -

i've confirmed issue in attempting compute glonball_2, don't see why it's producing error. function funct_2 should returning real numbers. "same size input" part, don't think i'm interpreting error message correctly. funct_2 takes 2 arguments , returns 1 value, funct_1, caused no error, that's not it. explain this? code:

function glonball = glonball(alpha) epsilon = 1; rmin = 0; rmax = 1; thmin = 0; thmax = 2*pi; funct_1 = @(r,th) (2).*(abs(alpha).^2-1).^(2)./abs(1-conj(alpha).*r.*exp(i.*th)).^4; glonball_1 = dblquad(funct_1, rmin, rmax, thmin, thmax); funct_2 = @(r,th) (abs(alpha.-r.*exp(i.*th))/abs(1-conj(alpha).*r.*exp(i.*th))).^2; glonball_2 = dblquad(funct_2, rmin, rmax, thmin, thmax); glonball = .5*glonball_1 + (1/((4).*epsilon^2))*glonball_2; end 

here's error receive when attempting run input argument between 0 , 1 (the area of interest):

error: quadcc: integrand f must return single, real-valued vector of same size input error: called from: error:   c:\software\octave-3.6.4\share\octave\3.6.4\m\general\dblquad.m @ line  72, column 10 error:    @ line -1, column -1 error: quadcc: integrand f must return single, real-valued vector error:   c:\software\octave-3.6.4\share\octave\3.6.4\m\general\dblquad.m @ line  65, column 5 error:   c:\software\octave-3.6.4\glonball.m @ line 10, column 13 

the .- unnecessary mention in comment above, doesn't cause errors in octave. give syntax error in matlab. similarly, / instead of ./ what's giving primary error.

after changing both of function ran fine in both octave 4.0.0 , matlab 2015a.

glonball(1) ans =     1.5708