Define a variable without assigning a value

Hi,

I want to create a variable m without assigning it a value, and do a calculation with it, is it possible?

Thnak you in advance,

R

[Stephen23]

You could just write a function:

https://www.mathworks.com/help/matlab/matlab_prog/create-functions-in-files.html

Answer 1

[Matt J]

Perhaps you are trying to do symbolic computations,

https://www.mathworks.com/help/symbolic/performing-symbolic-computations.html

If so, you need the Symbolic Math Toolbox.

[Jo Do]

Thank you so much. Just created an account to thank you.

[Matt J]

You are quite welcome. Please Accept-click the answer if it was useful to you.

Answer 2

[Tadios]

clc
clear
% close
snr = 20:5:60;
datanum = 10000;
M = 4;
K = [4, 10];
invber = zeros(2,length(snr));
reginvber = zeros(2,length(snr));
for ind1 = 1:1:length(snr)
    disp(['Signal to noise ratio: ' num2str(snr(ind1)) ' dB'])
    invtransmission
    ber = invtransmission(snr, K, datanum);
    invber4 = invtransmission(snr(ind1),K(1),datanum);
    reginvber4 = reginvtransmission(snr(ind1),K(1),datanum);
    invber10 = invtransmission(snr(ind1),K(2),datanum);
    reginvber10 = reginvtransmission(snr(ind1),K(2),datanum);
    invber(:,ind1) = [invber4; reginvber4];
    reginvber(:,ind1) = [invber10; reginvber10];
end

Signal to noise ratio: 20 dB

Unrecognized function or variable 'invtransmission'.

invber;
reginvber;
figure
semilogy(snr,invber(1,:),'r--x','linewidth',1.5)
hold on
semilogy(snr,invber(2,:),'r-d','linewidth',1.5)
semilogy(snr,reginvber(1,:),'b-+','linewidth',1.5)
semilogy(snr,reginvber(2,:),'b-*','linewidth',1.5)
xlabel('rho (dB)');ylabel('BER')
legend('4x4 Channal Inversion','4x4 Regularized Channal Inversion',...
    '10x10 Channal Inversion','10x10 Regularized Channal Inversion')

how to fix the problem " invtransmission4 = invtransmission(snr(ind1),K(1),datanum)"

[Walter Roberson]

The line you indicated as having a problem, does not appear in the code posted.

Functions invtransmission and reginvtransmission are not defined.

[Matt J]

@Tadios You've posted as an answer that doesn't appear to address the OP's question, or to be related to it in any way. I will delete it soon, but invite you to repost as a separate question.