function?z?=?zernfun（prthetanflag）
%???zernfun（prthetanflag）?returns?the?Pth?Zernike?functions?evaluated
%???at?positions?（RTHETA）?on?the?unit?circle.??P?is?a?vector?of?positive
%???integers?between?0?and?35?R?is?a?vector?of?numbers?between?0?and?1
%???and?THETA?is?a?vector?of?angles.??R?and?THETA?must?have?the?same
%???length.??The?output?Z?is?a?matrix?with?one?column?for?every?P-value
%???and?one?row?for?every?（RTHETA）?pair.
%
%???Z?=?ZERNFUN2（PRTHETA‘norm‘）?returns?the?normalized?Zernike
%???functions?defined?such?that?the?integral?of?（r?*?[Zp（rtheta）]^2）
%???over?the?unit?circle?（from?r=0?to?r=1?and?theta=0?to?theta=2*pi）
%???is?unity.??For?the?non-normalized?polynomials?max（Zp（r=1theta））=1
%???for?all?p.

%?Check?and?prepare?the?inputs:
%?-----------------------------
if?min（size（p））~=1
????error（‘zernfun2:Pvector‘‘Input?P?must?be?vector.‘）
end

if?any（p）>35
????error（‘zernfun2:P36‘?...
??????????[‘ZERNFUN2?only?computes?the?first?36?Zern