I keep getting A(I) = B, the number of elements in B and I must be the same. matlab error

2013 11 29
4 个回答
更新时间：2013 11 29
2 次查看（30 天）

0 个投票

last=0;
upflag=0;
p=zeros(length(detsq),1);
for i=1:length(detsq)
if(detsq(i)>1000)
if(upflag ==0)
if(last>0)
t= i-last;
p=1000/t*60
end
last=i;
end
upflag=100;
else
if(upflag>0)
upflag=upflag-1;
end
end
pulse(i)=p;
end
figure(3),plot(pulse)
In an assignment A(I) = B, the number of elements in B and I must be the same
This is the error keep popping. Any experts who can help me identify where I went wrong?

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回答（4 个）

Image Analyst
Image Analyst 2013-11-29

0 个投票

Is it your intention that p should be a vector, like you said here: p=zeros(length(detsq),1);
or is it your intention that p should be a scalar like you say here: p=1000/t*60
If you do this: pulse(i)=p; then p must be a scalar. Though I'm just guessing at the line of code producing the error because, for some strange reason, you left out that crucial part of the error message that identifies the line of code that caused the error.

2 个评论
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John
John 2013-11-29
%Step 8
det =filter (b2, 1, firs6);
figure(17),plot (det)
detsq=det .^2;
figure(18),plot(detsq)
last=0;
upflag=0;
p=zeros(length(detsq),1);
for i=1:length(detsq)
if(detsq(i)>0.1) %threshold
if(upflag ==0)
if(last>0)
t= i-last;
p=1000/t*60 %pulse rate
end
last=i;
end
upflag=100;
else
if(upflag>0)
upflag=upflag-1;
end
end
pulse(i)=p;
end
figure(19),plot(pulse)
I run again and line 25 which is pulse(i)=p the cause of the error. I show my full code for the whole program.
Image Analyst
Image Analyst 2013-11-29
Undefined function or variable 'b2'.
Error in test (line 3)
det =filter (b2, 1, firs6);

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John
John 2013-11-29

0 个投票

%step 3
function output = myFIR1(input,hn)
global in
in = [in input];
output =0;
r =(length(hn))*(length(in)>=length(hn))+(length(in))*(length(in)<length(hn));
for C = 0:r-1
output = output+(in(length (in)-C)*hn(C+1));
end
end
John
John 2013-11-29
编辑：John 2013-11-29

0 个投票

load 'ecg_8.dat'
y=ecg_8(:,2);
%Step 2
A=ecg_8(:,2)-mean(ecg_8(:,2));
fs=1000; %Sampling Frequency
t=0:1/fs:(length(ecg_8)-1)/fs;
B=((4.096+4.096)/4096)/1000; %converts data to millivolts
plot(t*1000,A*B*1000)
y2=fft(A);
L=length(y2);
freq=(0:fs/(L-1):fs);
plot(freq,abs(y2));
axis([0 500 0 3000000])
%step 4
n=(-100:100); %Set number of taps
w1=2*pi*0.03; %Cut-off frequency 1
w2=2*pi*0.08; %Cut-off frequency 2
h4=(1./(n*pi)).*(sin(w1*n)-sin(w2*n)); %Impulse Response
h4(101)=1+(w1-w2)/pi; %Sets middle value
h4=h4 .*blackman(201)'; %Mutilpied by Blackman function
figure(1);subplot(2,1,1),plot(20*log10(abs(fft(h4)))); %Plot in decibel against frequency
axis([-50 1050 -30 10]);
subplot(2,1,2),plot(h4);
for row=1:length(A)
firs4(row)=myFIR1(A(row),h4);
end
clearvars in row
figure(2),plot(firs4),title('Step 4 Impulse Response');
%step 5
n1=(-200:200);
ws=2*pi*0.008;
h5=-(sin(ws.*n1)./(n1*pi));
h5(201)=1-(ws/pi);
h5=h5 .*blackman(401)';
figure(3),subplot(2,1,1),plot(20*log10(abs(fft(h5))));
axis([-50 1050 -0.1 1.1]);
subplot(2,1,2),plot(h5);
for row=1:length(firs4)
firs5(row)=myFIR1(firs4(row),h5);
end
clearvars in row
figure(4),plot(firs5),title('Step 5')
xlabel('time (ms)'),ylabel('voltage(mv)')
%step 6
h6(1:501)=1;
h6(1:2)=0;
h6(500:501)=0;
h6(36:66)=0;
h6(501-65+1:501-35+1)=0;
plot(h6)
h=real(ifft(h6));
plot(h)
h2(1:251)=h(251:501);
h2(251:501)=h(1:251);
plot(h2);
h3=h2.*blackman(501)';
figure(5),plot(h3),title('Impulse Response');
xlabel('Frequency (Hz)'),ylabel('Ampltitude');
for row=1:length(firs5)
firs6(row)=myFIR1(firs5(row),h3);
end
clearvars in row
figure(6),plot(firs6),title('Step 6')
xlabel('Time(ms)'),ylabel('Voltage(mv)')
%Step 7
H=(A)*(B)*(1000);
hb1=H(4000:4600);
figure(7),plot(hb1)
b=flipud(hb1);
figure(8),plot(b) %Original Graph
xlabel('Frequency (Hz)'),ylabel('Amplitude'),title('Original Hb')
det=filter(b,1,H); %Original det vs Orignal Hb
figure(9),plot(det)
det=filter(b,1,firs5); %Original vs Step 5
figure(10),plot(det)
det=filter(b,1,firs6); %Original vs Step6
figure(11),plot(det)
w=firs6;
plot(w)
hb2=w(2200:2800);
figure(12),plot(hb2)
b2=fliplr(hb2);
figure(13),plot(b2) %Perfect Graph
det=filter(b2,1,H);
figure(14),plot(det) %Perfect vs original
det=filter(b2,1,firs5);
figure(15),plot(det) %Perfect vs step 5
det=filter(b2,1,firs6);
figure(16),plot(det) %Perfect vs step 6

5 个评论
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Image Analyst
Image Analyst 2013-11-29
Error using load
Unable to read file 'ecg_8.dat': no such file or directory.
Error in test2 (line 1)
load 'ecg_8.dat'
John
John 2013-11-29
编辑：John 2013-11-29
Sir, what is the exact problem that causes the program not able to run the last step? Can you let me know which one needs to change? Thank you!
Image Analyst
Image Analyst 2013-11-29
You can't have negative or fractional indexes, OR stuff a bunch of elements into a single element. Step through your code until it throws an error, then examine all the variables and see what violates what I said in the first sentence of this comment.

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John
John
2013-11-29

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Image Analyst
Image Analyst
2013-11-29

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