A little help?
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Hi there,
I am having a little problem with one of the questions for an assignment I have. I have less than basic knowlage of MALAB so this assignment is to break me in so to say.
The question states that I need to create a matrix with with the input values clamped in the range +- 1.
Any help would be much appreciated! :D
采纳的回答
Image Analyst
2011-12-11
Aadam: Based on your latest comment to your original question I would just make my code into a function. In file test.m:
function test()
% Generate sample data.
M = 10*rand(8) - 5; % Sample matrix.
% Clip the data to the range -1 to +1
oneabs = Clip(M)
% Clip to range (-1 to +1) if outside that range.
% Leave values alone if within that range.
function oneabs = Clip(M)
oneabs = M; % Initialize.
oneabs (M < -1) = -1;
oneabs (M > 1) = 1;
更多回答（5 个）
Fangjun Jiang
2011-12-11
Matrix=[-0.1,0.2;-0.5,0.9]
Based on your latest update in comments, here is a solution
InMatrix=4*rand(5)-2;
OutMatrix=min(InMatrix,1);
OutMatrix=max(OutMatrix,-1)
1 个评论
Jan
2011-12-11
@Fangjun: "create a matrix with with the input values clamped in the range +- 1". Yes! I like the deeper message of this answer. +1
@Aadam: I do not think, that this answer solves your problem.
Mohsen Davarynejad
2011-12-11
Matrix = 2*rand(10,10) - 1
5 个评论
Aadam
2011-12-11
Mohsen Davarynejad
2011-12-11
B = A - 1;
C=2*B./max(B(:))-1;
Aadam
2011-12-11
Mohsen Davarynejad
2011-12-11
Follow this:
B = A - min(A(:));
C=B./max(B(:));
D=2*C;
E=D-1;
Image Analyst
2011-12-11
You're scaling his data, which he didn't ask for.
Image Analyst
2011-12-11
M = 10*rand(8) - 5; % Sample matrix.
% Now clip to range (-1 to +1)
M(M<-1) = -1;
M(M>1) = 1;
4 个评论
Aadam
2011-12-11
Image Analyst
2011-12-11
Yeah, so? That's what this code does - leaves values between -1 and 1 alone and clips values outside that range. If you need to read the file, then say so - you can use things like csvread, dlmread, etc. At first you said you need to create a matrix, but I guess you could create it by reading a file. To display, merely put the name of the array on its own line, like this:
M
Aadam
2011-12-11
Image Analyst
2011-12-11
No you didn't try it. You didn't try my code because I never mentioned oneabs. In fact I just copied and pasted my code into MATLAB, now that I'm on a computer that has it, and it ran fine and did exactly what I said and what you asked. You'd need to post your code for us to figure out what you did wrong.
Jan
2011-12-11
Another approach:
M = 10*rand(8) - 5; % Sample matrix. (Thanks IA!)
M = max(min(M, 1), -1);
Mohsen Davarynejad
2011-12-11
The Matrix of interest of poster is:
A = [1,2,3;4,5,6;7,8,9];
and the soloution is the following:
B = A - min(A(:));
C=2*B./max(B(:))-1;
4 个评论
Image Analyst
2011-12-11
Why do you say that? I don't agree with that at all. You're scaling the data to make it fit in the range. Data values in the range will get changed if you do that. He didn't say anything about wanting to scale his data - he just wants to clamp/clip his data that went outside of the range.
Jan
2011-12-11
@Mohsen: Do you have personal contact to the OP? How do you know that the poster asks for [1,2,3; 4,5,6; 7,8,9]?
Mohsen Davarynejad
2011-12-11
@ Jan: Please take a look at Aadam's comment on my first post above, were he introduces his Matrix and asks for extra information on my code.
@ Image Analyst: Looking at the A matrix Aadam has in mind, the way you go is not correct!! The matrix elemets are between 1 and 9.
Image Analyst
2011-12-11
Mohsen, that matrix was in response to your question and as I mentioned it's not what any of us suggested because he somehow came up with some new matrix oneabs. So who knows why he cam up with that. Now if his matrix were really that (in the range 1-9) the simplest solution would simply be M = ones(1, length(M)); Of course he'd have no values less than 1 so there's be no reason to clip there like he originally required. But he said he DID need to clamp to -1 in his question and subject line. Neither Jan nor I sees anything at all where he says "scale my data" like you gave but we do see where he says "clamp my data." Though I do agree that your code does scale, which is fine if that's what he wants (despite saying something to the contrary). Aadam, please clarify: do you want scaling or clamping?
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