I got this error after run this program:- Improper assignment with rectangular empty matrix. Error in signal (line 2) [R_A(i), R_t(i)]=ma​x(sigL(lef​t(i):right​(i))); please help me out

 sig = load('NEW.m');
 N = length(sig);
 fs = 200;
 t = [0:N-1]/fs;
 figure(1);subplot(4,2,1);plot(sig);
title('Original Signal');
b = 1/32*[1 0 0 0 0 0 -2 0 0 0 0 0 1];

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 title('Original Signal');
 b = 1/32*[1 0 0 0 0 0 -2 0 0 0 0 0 1];
 a = [1 -2 1];
 sigL=filter(b,a,sig);
 subplot(4,2,3); plot(sigL)
 title('Low Pass Filter')
 subplot(4,2,4);zplane(b,a)
b = [-1/32 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 -1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1/32];
a = [1 -1];
 sigH = filter(b,a,sigL);
 subplot(4,2,5);plot(sigH)
 title('High Pass Filter')
 subplot(4,2,6);zplane(b,a)
 b = [1/4 1/8 0 -1/8 -1/4];
 a=[1];
 sigD = filter(b,a,sigH);
 subplot(4,2,7);plot(sigD);
 title('Derivative Base Filter')
 subplot(4,2,8);zplane(b,a)
 sigD2 = sigD.^2;
 signorm = sigD2/max(abs(sigD2));
 h = ones(1,31)/31;
 sigAV = conv(signorm,h);
 sigAV = sigAV(15+[1:N]);
 sigAV = sigAV/max(abs(sigAV));
 figure(2);plot(sigAV)
 title('Moving Average Filter')
 threshold = mean(sigAV);
 P_G = (sigAV>0.01);
 figure(3); plot(P_G);
 title('Threshold Signal')
 figure; plot(sigL)
 difsig = diff(P_G);
 left = find(difsig==1);
 right = find(difsig==-1);
 for i=1:length(right);
    [R_A(i), R_t(i)]=max(sigL(left(i):right(i)));
    R_t(i)=R_t(i)-1+left(i); %add offset
   
    [Q_A(i), Q_t(i)]=min(sigL(left(i):R_t(i)));
    Q_t(i)=Q_t(i)-1+left(i);
  
    [S_A(i), S_t(i)]=min(sigL(left(i):right(i)));
    S_t(i)=S_t(i)-1+left(i);
    
    [P_A(i), P_t(i)]=max(sigL(left(i):Q_t(i)));
    P_t(i)=P_t(i)-1+left(i);
    
    [T_A(i), T_t(i)]=max(sigL(S_t(i):right(i)));
    T_t(i)=T_t(i)-1+left(i)+47;
    
end