FRFT程序运行时说Not enough input arguments. 是怎么回事？？？

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如题：FRFT程序运行时说Not enough input arguments. 是怎么回事？？？
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function Faf = frft(f, a)
% The fast Fractional Fourier Transform
+ h9 L  I; J, Z( p% input: f = samples of the signal
% a = fractional power
% output: Faf = fast Fractional Fourier transform

error(nargchk(2, 2, nargin));

f = f(;
N = length(f);
5 y& H6 b1 d. P# i8 Yshft = rem((0:N-1)+fix(N/2),N)+1;
* ^6 `! J; I% }" rsN = sqrt(N);
a = mod(a,4);

% do special cases
. R5 f3 \) W* Q" B, v6 e  o% Pif (a==0), Faf = f; return; end;
0 Q3 R) Q' }4 r, o% C; b% [3 R' Tif (a==2), Faf = flipud(f); return; end;
) [- r' G- z6 H/ I9 t8 ?; Jif (a==1), Faf(shft,1) = fft(f(shft))/sN; return; end
if (a==3), Faf(shft,1) = ifft(f(shft))*sN; return; end

% reduce to interval 0.5 < a < 1.5
. R$ ~. V4 h  A. T+ k! uif (a>2.0), a = a-2; f = flipud(f); end
if (a>1.5), a = a-1; f(shft,1) = fft(f(shft))/sN; end
if (a<0.5), a = a+1; f(shft,1) = ifft(f(shft))*sN; end

% the general case for 0.5 < a < 1.5
alpha = a*pi/2;
tana2 = tan(alpha/2);
# S4 J" J5 X9 m+ Isina = sin(alpha);
; b0 |2 Z3 ^$ Uf = [zeros(N-1,1) ; interp(f) ; zeros(N-1,1)];

% chirp premultiplication
, c+ [' k7 z* U3 Rchrp = exp(-i*pi/N*tana2/4*(-2*N+2:2*N-2)'.^2);
, ^6 ?5 z; g3 \1 k, y3 m. B4 ]6 L& Yf = chrp.*f;

% chirp convolution
c = pi/N/sina/4;
Faf = fconv(exp(i*c*(-(4*N-4):4*N-4)'.^2),f);
" o& x/ ]( g: r$ u2 Z' HFaf = Faf(4*N-3:8*N-7)*sqrt(c/pi);

% chirp post multiplication
& F8 b7 |: _( ]0 \, R: N- zFaf = chrp.*Faf;

% normalizing constant
Faf = exp(-i*(1-a)*pi/4)*Faf(N:2:end-N+1);

%%%%%%%%%%%%%%%%%%%%%%%%%
function xint=interp(x)
' D7 h5 z$ W' B1 v% sinc interpolation

N = length(x);
; x/ X/ }: l2 \9 Gy = zeros(2*N-1,1);
y(1:2:2*N-1) = x;
, Z3 c. f2 i0 @1 E7 ?( Axint = fconv(y(1:2*N-1), sinc([-(2*N-3)2*N-3)]'/2));
1 V9 t. y/ A( y$ {5 c  P0 d- U$ exint = xint(2*N-2:end-2*N+3);

%%%%%%%%%%%%%%%%%%%%%%%%%
. y- ~9 Q6 \- y! l1 I1 ufunction z = fconv(x,y)
% convolution by fft

N = length([x(;y(])-1;
P = 2^nextpow2(N);
  _! _# j" p& g( {  ^+ @  F0 F( Ez = ifft( fft(x,P) .* fft(y,P));
' ~, c7 f% Q$ m4 Nz = z(1:N);

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xixihahaheihei

好复杂