School of Computer Science
Computer Science COMP 199 (Winter term)
Excursions in Computing Science
%MATLABpak11: flipflopNandAll, flipflopSettle, flipflopNandFEall,
% flipflopWrite, flipflopRead, booleanFA, booleanFAeval, booleanRevPolEval,
% push, pop
% function [w,x,y,z] = flipflopNandAll(w,x,y,z)
% THM 060828
function [w,x,y,z] = flipflopNandAll(w,x,y,z)
y1 = y;
z1 = z;
y = nand(w,z1);
z = nand(x,y1);
% function [w,x,y,z] = flipflopSettle(w,x,y,z)
% THM 060828
function [w,x,y,z] = flipflopSettle(w,x,y,z)
[w,x,y,z] = flipflopNandAll(w,x,y,z);
[w,x,y,z] = flipflopNandAll(w,x,y,z);
% function [data,enable,y,z] = flipflopNandFEall(data,enable,y,z)
% THM 060828
% nand flipflop prefaced by nand front end
function [data,enable,y,z] = flipflopNandFEall(data,enable,y,z)
w = nand(data,enable);
x = nand(not(data),enable);
[w,x,y,z] = flipflopSettle(w,x,y,z);
% function y = flipflopwrite(data,y)
% THM 060828
function y = flipflopWrite(data,y)
[data,enable,y,z] = flipflopNandFEall(data,1,y,not(y));
% function y = flipflopRead(data,y)
% THM 060828
function y = flipflopRead(data,y)
[data,enable,y,z] = flipflopNandFEall(data,0,y,not(y));
% function ok = booleanFA(expression)
% THM 060828
% triples[1+statebefore,1+plus|letter|other] = stateafter
% plus = 2; letter = 1; other = 0;
function ok = booleanFA(expression)
%triples = [0,0,3;
% 0,1,1;
% 0,2,3;
% 1,0,3;
% 1,1,1;
% 1,2,2;
% 2,0,3;
% 2,1,1;
% 2,2,3;
% 3,0,3;
% 3,1,3;
% 3,2,3
% ];
triples = [3,1,3; %plus 3 2 3 3
3,1,2; %letter 1 1 1 3
3,1,3; %other 3 3 3 3
3,3,3 % state 0 1 2 3
];
state = 0;
for pos = 1:length(expression)
if expression(pos)=='+', input = 2;
elseif isletter(expression(pos)), input = 1;
else input = 0; end
state = triples(1+state,1+input);
end
ok = state==1;
% function value = booleanFAeval(expression,identifiers,values)
% THM 060828
% triples[1+statebefore,1+plus|letter|other] = stateafter
% actions[1+statebefore,1+plus|letter|other] = eval|and|or|nop
% plus = 2; letter = 1; other = 0;
% eval = 'e'; and = 'a'; or = 'o'; nop = 'n';
function value = booleanFAeval(expression,identifiers,values)
triples = [3,1,3; %plus 3 2 3 3
3,1,2; %letter 1 1 1 3
3,1,3; %other 3 3 3 3
3,3,3 % state 0 1 2 3
];
actions = ['nen'; %plus n n n n
'nan'; %letter e a o n
'non'; %other n n n n
'nnn'; % state 0 1 2 3
];
state = 0;
for pos = 1:length(expression)
current = expression(pos);
if current=='+', input = 2;
elseif isletter(current)
input = 1;
currval = lookup(current,identifiers,values);
else input = 0; end
action = actions(1+state,1+input);
if action=='e', value = currval;
elseif action=='a', value = and(value,currval);
elseif action=='o', value = or(value,currval);
end
state = triples(1+state,1+input);
end
if state~=1, value = -1; end
% function value = booleanRevPolEval(expression,identifiers,values)
% THM 060828
% letter: evaluate and push onto stack; operator: pop stack twice, push result
% e.g. of identifiers = 'abcd'
% e.g. of values = [1,1,1,0]
% e.g. of use
% booleanRevPolEval('ab.cd.+',identifiers,values)
% e.g. of use with shuntingYard:
% booleanRevPolEval(shuntingYard('((a.b)+(c.d))'),identifiers,values)
function value = booleanRevPolEval(expression,identifiers,values)
stack = [-1,-1,-1,-1,-1,-1,-1,-1,-1,-1]; top = 1;
for pos = 1:length(expression)
current = expression(pos);
if current=='+'
[x,stack,top] = pop(stack,top); %pop, push for integer stack
if x<0 | 1<x
value = -1;
return
end
[y,stack,top] = pop(stack,top);
if y<0 | 1<y
value = -1;
return
end
[stack,top] = push(or(x,y),stack,top);
elseif current=='.'
[x,stack,top] = pop(stack,top);
if x<0 | 1<x
value = -1;
return
end
[y,stack,top] = pop(stack,top);
if y<0 | 1<y
value = -1;
return
end
[stack,top] = push(and(x,y),stack,top);
elseif isletter(current)
currval = lookup(current,identifiers,values);
[stack,top] = push(currval,stack,top);
else
value = -1;
return
end
end
[value,stack,top] = pop(stack,top);
% function [stack,top] = push(value,stack,top)
% THM 060828
function [stack,top] = push(value,stack,top)
if top >= length(stack)
return
else
stack(top) = value;
top = top + 1;
end
% function [value,stack,top] = pop(stack,top)
% THM 060828
function [value,stack,top] = pop(stack,top)
if top < 2
value = -1
return
else
top = top - 1;
value = stack(top);
stack(top) = -1;
end
% function concretePoetry
% THM 060911
% invokes
% state = getNextState(automaton,state);
% word = getNextWord(adj);
% sentence = appendWord(sentence,truncate(word));
%function concretePoetry
adj = ['bright ';'common ';'found ';'friendly';'good ';'hostile ';'little ';'our ';'retold ';'same ';'sought ';'spoken ';'your '];
adv=['gently ';'just ';'not ';'probably';'there ';'too '];
art = ['a'];
conj = ['& ';'so'];
noun = ['armour ';'bridging ';'chickadee ';'colosseum ';'distance ';'effort ';'fire ';'forgiveness';'game ';'hope ';'light ';'moon ';'news ';'patience ';'pluto ';'point ';'realties ';'satellites ';'shirts ';'song ';'speck ';'thoughts ';'view ';'views ';'wisdom '];
prep = ['back';'for ';'onto';'of ';'to ';'with'];
pron = ['this';'you '];
verb = ['are ';'be ';'crashing ';'is ';'press ';'reflecting';'spins '];
encodeState = ['start';'adj ';'adv ';'art ';'noun ';'prep ';'pron ';'verb ';'stop ']; % not used, but explains the integer entries in automaton:
automaton = [1,2,0,1/2; 1,5,1/2,5/6; 1,4,10/12,11/12; 1,7,11/12,1; 2,5,0,4/7; 2,2,4/7,6/7; 2,9,6/7,1; 3,8,0,1/3; 3,4,1/3,2/3; 3,3,4/6,5/6; 3,9,5/6,1; 4,2,0,1/2; 4,5,1/2,1; 5,5,0,8/25; 5,6,8/25,14/25; 5,9,14/25,19/25; 5,8,19/25,23/25; 5,2,23/25,24/25; 5,3,24/25,1; 6,5,0,5/11; 6,2,5/11,7/11; 6,8,7/11,9/11; 6,3,9/11,10/11; 6,7,10/11,1; 7,8,0,3/4; 7,3,3/4,1; 8,3,0,1/2; 8,4,1/2,5/6; 8,8,5/6,11/12; 8,9,11/12,1 ];
sentence = '';
state = 1;
while state~=9
state = getNextState(automaton,state);
switch state
case 2
word = getNextWord(adj);
case 3
word = getNextWord(adv);
case 4
word = getNextWord(art);
case 5
word = getNextWord(noun);
case 6
word = getNextWord(prep);
case 7
word = getNextWord(pron);
case 8
word = getNextWord(verb);
case 9
break
end
sentence = appendWord(sentence,truncate(word));
end
sentence
% function state = getNextState(automaton,oldState,which)
% THM 060911
% transfer from one part of speech to another (adj,adv,art,noun,prep,pron,verb)
% invoked by concretePoetry
function state = getNextState(automaton,oldState)
which = rand;
sizes = size(automaton);
for j = 1:sizes(1)
if (automaton(j,1)==oldState) and (automaton(j,3)≤which) and (which<automaton(j,4))
state = automaton(j,2); return
end
end
% function word = getNextWord(partOfSpeech)
% THM 060911
% pick any word, with equal probability, from a part of speech array
% invoked by concretePoetry
function word = getNextWord(partOfSpeech)
sizes = size(partOfSpeech);
next = ceil(rand * sizes(1));
word = partOfSpeech(next,:);
% function sentence = appendWord(sentence,word)
% THM 060911
% invoked by concretePoetry
function sentence = appendWord(sentence,word)
lenS = length(sentence);
sentence(lenS+1) = ' '; % separate with a space
lenW = length(word);
for j = 1:lenW
sentence(lenS+j+1) = word(j);
end