Mercurial > hg > camir-aes2014
annotate toolboxes/FullBNT-1.0.7/KPMtools/ind2subvKPM.m @ 0:e9a9cd732c1e tip
first hg version after svn
| author | wolffd |
|---|---|
| date | Tue, 10 Feb 2015 15:05:51 +0000 |
| parents | |
| children |
| rev | line source |
|---|---|
| wolffd@0 | 1 function sub = ind2subvKPM(siz, ndx) |
| wolffd@0 | 2 % IND2SUBV Like the built-in ind2sub, but returns the answer as a row vector. |
| wolffd@0 | 3 % sub = ind2subv(siz, ndx) |
| wolffd@0 | 4 % |
| wolffd@0 | 5 % siz and ndx can be row or column vectors. |
| wolffd@0 | 6 % sub will be of size length(ndx) * length(siz). |
| wolffd@0 | 7 % |
| wolffd@0 | 8 % Example |
| wolffd@0 | 9 % ind2subv([2 2 2], 1:8) returns |
| wolffd@0 | 10 % [1 1 1 |
| wolffd@0 | 11 % 2 1 1 |
| wolffd@0 | 12 % ... |
| wolffd@0 | 13 % 2 2 2] |
| wolffd@0 | 14 % That is, the leftmost digit toggle fastest. |
| wolffd@0 | 15 % |
| wolffd@0 | 16 % See also SUBV2IND |
| wolffd@0 | 17 |
| wolffd@0 | 18 n = length(siz); |
| wolffd@0 | 19 |
| wolffd@0 | 20 |
| wolffd@0 | 21 if n==0 |
| wolffd@0 | 22 sub = ndx; |
| wolffd@0 | 23 return; |
| wolffd@0 | 24 end |
| wolffd@0 | 25 |
| wolffd@0 | 26 if all(siz==2) |
| wolffd@0 | 27 sub = dec2bitv(ndx-1, n); |
| wolffd@0 | 28 sub = sub(:,n:-1:1)+1; |
| wolffd@0 | 29 return; |
| wolffd@0 | 30 end |
| wolffd@0 | 31 |
| wolffd@0 | 32 cp = [1 cumprod(siz(:)')]; |
| wolffd@0 | 33 ndx = ndx(:) - 1; |
| wolffd@0 | 34 sub = zeros(length(ndx), n); |
| wolffd@0 | 35 for i = n:-1:1 % i'th digit |
| wolffd@0 | 36 sub(:,i) = floor(ndx/cp(i))+1; |
| wolffd@0 | 37 ndx = rem(ndx,cp(i)); |
| wolffd@0 | 38 end |
| wolffd@0 | 39 |
| wolffd@0 | 40 |
| wolffd@0 | 41 |
| wolffd@0 | 42 %%%%%%%%%% |
| wolffd@0 | 43 |
| wolffd@0 | 44 function bits = dec2bitv(d,n) |
| wolffd@0 | 45 % DEC2BITV Convert a decimal integer to a bit vector. |
| wolffd@0 | 46 % bits = dec2bitv(d,n) is just like the built-in dec2bin, except the answer is a vector, not a string. |
| wolffd@0 | 47 % n is an optional minimum length on the bit vector. |
| wolffd@0 | 48 % If d is a vector, each row of the output array will be a bit vector. |
| wolffd@0 | 49 |
| wolffd@0 | 50 |
| wolffd@0 | 51 if (nargin<2) |
| wolffd@0 | 52 n=1; % Need at least one digit even for 0. |
| wolffd@0 | 53 end |
| wolffd@0 | 54 d = d(:); |
| wolffd@0 | 55 |
| wolffd@0 | 56 [f,e]=log2(max(d)); % How many digits do we need to represent the numbers? |
| wolffd@0 | 57 bits=rem(floor(d*pow2(1-max(n,e):0)),2); |