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Diffstat (limited to 'viterbi_generator/tests/utils/make_previous.m')
| -rw-r--r-- | viterbi_generator/tests/utils/make_previous.m | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/viterbi_generator/tests/utils/make_previous.m b/viterbi_generator/tests/utils/make_previous.m new file mode 100644 index 0000000..678fa43 --- /dev/null +++ b/viterbi_generator/tests/utils/make_previous.m @@ -0,0 +1,54 @@ +function [ PREVIOUS ] = make_previous(SYMBOLS) +% +% MAKE_PREVIOUS: +% This function returns a lookuptable containing a mapping +% between the present state and the legal previous states. +% Each row correspond to a state, and the two legal states +% related to state n is located in PREVIOUS(n,1) and in +% previous(n,2). States are represented by their related +% numbers. +% +% SYNTAX: [ PREVIOUS ] = make_previous(SYMBOLS) +% +% INPUT: SYMBOLS: The table of symbols corresponding the the state- +% numbers. +% +% OUTPUT: PREVIOUS: +% The transition table describing the legal previous +% states asdescribed above. +% +% SUB_FUNC: None +% +% WARNINGS: None +% +% TEST(S): Verified against expected result. +% +% AUTOR: Jan H. Mikkelsen / Arne Norre Ekstrøm +% EMAIL: hmi@kom.auc.dk / aneks@kom.auc.dk +% +% $Id: make_previous.m,v 1.3 1997/09/22 08:14:27 aneks Exp $ + +% FIRST WE NEED TO FIND THE NUMBER OF LOOPS WE SHOULD RUN. +% THIS EQUALS THE NUMBER OF SYMBOLS. ALSO MAXSUM IS NEEDED FOR +% LATER OPERATIONS. +% +[ states , maxsum ]=size(SYMBOLS); + +maxsum=maxsum-1; +search_matrix=SYMBOLS(:,1:maxsum); + +% LOOP OVER THE SYMBOLS. +% +for this_state=1:states, + search_vector=SYMBOLS(this_state,2:maxsum+1); + k=0; + for search=1:states, + if (sum(search_matrix(search,:)==search_vector)==maxsum) + k=k+1; + PREVIOUS(this_state,k)=search; + if k > 2, + error('Error: identified too many previous states'); + end + end + end +end
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