Queries on Quantization input

Does anyone understand the input of this code ? does the vect represent a matrix and how do i determine the input for bits?

function [levelNumbers,scaling] = quantization(vect,bits)

%...'levelNumbers' contains the index of the quantization value
%...'scaling' contains 2 values, the lowest quant. value and delta     

[M,N] = size(vect);
if (M>1)
     vect = vect';
end

range = max(vect)-min(vect);
delta = roundVal(range/2^(bits));

levels = 2^bits;
base   = roundVal(min(vect));

%quantValues  = [base : delta : roundVal(max(vect)-delta)]' + delta/2;
quantValues  = [base : delta : roundVal(max(vect)-delta)]';

inputArray = repmat(vect       , length(quantValues), 1           );
quantArray = repmat(quantValues, 1                  , length(vect));

quantDiff = abs(inputArray-quantArray);
[Y,I] = min(quantDiff);

quantResults=quantArray(I);
for i=1:length(quantResults)
     levelNumbers(i) = find(quantResults(i)==quantValues);
end
scaling = [base, delta];

if length(quantResults)==0
   levelNumbers=ones(1,length(vect));
end

function newVal = roundVal(num)
   num = num*1e4;
   num = round(num);
   newVal = num*1e-4;

Answer 1

[Walter Roberson]

The vect must be a vector, but it can be row order or column order.

The number of bits would be as appropriate for your purposes. 1 bit if you want 2 quantization levels, 2 bits if you want 4 levels, 3 bits if you want 8 levels, and so on.

[Derick Wong]

I am not sure because now my vector is stick together[x1 y1 z1; x2 y2 z2;x3 y3 z3]. And so now it is a matrix. Can I just input my matrix just like that ? how do you actually know how many number of lvl you need, is it base on my matrix ?

[Walter Roberson]

You can reshape() your matrix into a vector before passing it in.

The number of levels you need is not directly related to the matrix; it is based upon your purpose in quantizing. Which you have not happened to mention

[Derick Wong]

My purpose is to do compression. I had to do a compression by going through DCT(discrete cosine transformation) follow by quantization. I have a matrix of

[x1 x2 x3 x4 ... xm
 y1 y2 y3 y4 ... ym
 z1 z2 z3 z4 ... zm]

In fact there are n rows as well. Initially I used round() as a form of quantization , but now I need to do a inverse quantization which needed me to use this quantization code and another inverse quantization code.