"Array exceed the predefined size"

I'm running a simple program, and sometimes(yeah) i would be stuck in the following error:

"Matlab array exceeds the preset maximum array size"

What's more, it said that i wanted to create an array with size of 1x18446744073709551615 (17179869184.0GB)

OMG....

I'm just concating two arrays...

"player = [player,deck(1)]; deck = deck(2:end); "

From the environment section, i saw that the array was all fine, but when i click the botton to step, the program abort.

the player and deck are just two small arrays.

HELP.

[Walter Roberson]

18446744073709551615

That just happens to be 2^64 - 1

What is the data type of player? And of deck?

[darova]

PLease show the whole code

[Liming Fang]

Here is the main part of the code which i think is problematic

It's just an simulation of blackjack

clc;clear;
N_EPISODES = 4e5;

N_PLAYER_VALUE = 21-12+1;
N_DEALER_VALUE = 13;
N_ACE = 2;
N_ACTION = 2;

tic
for i=1:N_EPISODES
    deck = shufflecards();
    stateseen = [];
    
    player = deck(1:2); deck = deck(3:end);
    dealer = deck(1:2); deck = deck(3:end);
    dealer_showed = dealer(1);
    phv = handValue(player);
    dhv = handValue(dealer);
    
    while(phv<12)
        player = [player,deck(1)];  deck = deck(2:end);
        phv = handValue(player);
    end
    
    si = 1;
    action = unidrnd(2)-1;

    state = stateFromHand(player,dealer_showed);
    P(sub2ind([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE],state(1,1)-11,state(1,2),state(1,3)+1)) = action;
    stateseen(si,:) = state;
    
    while((phv<=21)&&(action))
        player = [player,deck(1)];  deck = deck(2:end); phv = handValue(player);
        state = stateFromHand(player,dealer_showed);
        stateseen(end+1,:) = state;
        
        if(phv<=21)
            si = si+1;
            action = P(sub2ind([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE],state(1)-11,state(2),state(3)+1));
        end
    end
    
    % dealer's turn
    while(dhv<17)
        dealer = [dealer,deck(1)];  deck = deck(2:end);
        dhv = handValue(dealer);
    end
end
toc

And the error occurs in line22

"player = [player,deck(1)]; deck = deck(2:end);"

Oh, the shufflecards equals "randperm(52)"

function [hv,usableAce] = handValue(hand)
% it calculates the all of the cards number in my hand
% handValue([10 11]) ->20
% compute 1:13 indexing for each card: 
values = mod( hand - 1, 13 ) + 1; 
% map face cards (11,12,13)'s to 10's: 
values = min( values, 10 );
sv     = sum(values); 
% Promote soft ace
if (any(values==1)) && (sv<=11)
   sv = sv + 10;
   usableAce = 1; 
else
   usableAce = 0; 
end

hv = sv; 




function [st] = stateFromHand(hand,cardShowing)
%
% Returns the state (a three vector of numbers for a given hand of cards)
% 
% [players current sum, dealar showing card, usable ace] 
% 
% Cards are enoumerated 1:52, such that
% 
%  1:13 => A, 2, 3, ..., 10, J, Q, K      (of C)
% 14:26                                   (of D)
%                                         (of H)
%                                         (of S)

[hv,usableAce] = handValue(hand);

cardShowing = mod( cardShowing - 1, 13 ) + 1; 

st = [ hv, cardShowing, usableAce ]; 

return; 

Answer 1

[Walter Roberson]

I am not seeing that error.

I had to guess what your shufflecards function does.

I encounter

Index exceeds the number of array elements (14).

Error in jackall (line 39)
            action = P(sub2ind([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE],state(1)-11,state(2),state(3)+1));

Which makes sense. You do not initialize P, and you store into

P(sub2ind([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE],state(1,1)-11,state(1,2),state(1,3)+1)) = action;

which builds it out to a certain size. Then you

state = stateFromHand(player,dealer_showed);

which changes state, and you try to do

            action = P(sub2ind([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE],state(1)-11,state(2),state(3)+1));

but since the first element of the state increased due to the additional card being taken into account, the right hand side is trying to index into P at a location beyond what you initialized.

[Liming Fang]

Hi, i have upload my source code for these functions.

[Walter Roberson]

I did guess that shufflecards was randperm(52)

>> type shufflecards.m

function shuffled = shufflecards()
    shuffled = randperm(52);
end

I used your exact code other than guessing (correctly) for shufflecards, and I encountered the error message I indicated above.

[Liming Fang]

emm,sorry, indeed, i initialized "P". I just forgot to upload it.

Q = zeros(prod([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE]),N_ACTION);
P = ones(prod([N_PLAYER_VALUE,N_DEALER_VALUE,N_ACE]),1);

These two sentences are at the top of the .m file