CODE error correction

HI all,

would somebody please help me find out what should i do to plot and correct this script?

clear
clc;
B=1000; L=2000;Df=200; Sgama=.8;
nsamples=3000;
rmem = zeros(3,nsamples);
qult = zeros(1,nsamples);
for K=1:nsamples
  while true
  C = normrnd(620,147.64);
  if C<=450 || C >= 800 || ismember(C,rmem(1,1:K-1)); continue; end
   gama = normrnd(1.96,0.02);
  if gama <= 1.92 || gama >= 1.98 || ismember(gama,rmem(2,1:K-1)); continue; end
   fi = normrnd(3.76,1.1034);
  if fi <= 2.7 || fi >= 16.3 || ismember(fi,rmem(3,1:K-1)); continue; end
  rmem(:,K) = [C; gama; fi];
   break
  end
   q=107.25+(100*fi);
   dq=1+(.4*tan(fi*pi/180)*(1-sin(fi*pi/180)^2));
   Sq=1+(.5*sin(fi*pi/180));
   Nq = tan((pi/4)+(pi*fi/360)) * tan((pi/4)+(pi*fi/360)) * exp(pi*tan(fi*pi/180));
   Nc = (Nq-1)*cot(fi*pi/180);
   Sc=1+(.5* Nq / Nc);
    Ngama = 2*(Nq+1)*tan(fi*pi/180);
    qult(K)=(1.08*C*Nc*Sc)+(q*Nq*Sq*dq)+(429*Ngama);
  end
surf( C(1,1:nsamples), fi(1,1:nsamples), qult );
,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,

ERROR :

??? Index exceeds matrix dimensions.

Error in ==> graphQ at 27 surf( C(1,1:nsamples), fi(1,1:nsamples), qult );

[dimuthu chathuranga]

eroor occur communication somebody help me

Answer 1

[UJJWAL]

Hi ,

I don't see any reason as to why thic code should not give an error. C is not a vector. It is a single number(or let us say C is a vector of dimension 1 by 1. In the surf function you are trying to access C(1,1:nsamples) which obviously goes beyond the length of C . So an error must occour.

As far as correction is concerned, it is difficult unless you tell the nature of this code and what it is that you want to do. I defined a vector C1 and stored the individual values of C in it. I did the same for fi . However in that case surf would not work as it will require a 2D matrix in the form of qult to work. I believe that you want to plot qult for corresponding values of C and fi. However for that u need to use Plot3. I used it but I got something weird. So unless the nature of the code is not made clear it is extremely difficult to comment on the nature of the solution.

Happy to Help

[Walter Roberson]

Good point about surf() being the wrong call.

[Walter Roberson]

UUJWAL is correct: with that flow of code, you will need to store each accepted C and fi value. Just before your q= assignment would seem to be an appropriate location.

Answer 2

[Vikash Anand]

clc;
clear all;
close all;
n=7;k=4;
num_bit=10000;
genpoly=cyclpoly(n,k,'max');
SNRdB=0:10;
SNR=10.^(SNRdB/10);
for i=1:length(SNR)
 msg = randi(num_bit,k,[0,1]);
 code=encode(msg,n,k,'cyclic/binary',genpoly);
 [row, column]=size(code);
 codevec=reshape(code.',1,row*column);
 noise=awgn(codevec,SNRdB(i));
 y=codevec+noise;
 error=0;
 for j=1:length(y)
 if (y(j)>1&&codevec(j)==0)||(y(j)<0&&codevec(j)==1) 
 error=error+1;
 end
 end
 error=error/num_bit; 
m(i)=error;
end
y(y>0)=1;
 y(y<0)=0;
 decode_y=decode(y,n,k,'cyclic/binary',genpoly);
 decmsg=reshape(decode_y,num_bit,k);
 semilogy(SNRdB,m,'r','linewidth',2),grid on;
title(' Bit Error Rate verses SNR for Cyclic Code');
xlabel(' SNR(dB)');
ylabel('BER');