Fast method of Initialization of logicals into cells

Hi....i'd like to make a large cell array (that contains empty logicals) and i want to see if theres anyway to do it faster than the way im currently doing it....

my way is described below...

temp_allzeros = false(size(config.MIDlist,1),1);
allzeros = cell(size(config.MIDlist,1),1);

for i = 1:length(temp_allzeros)
    allzeros(i) = temp_allzeros(i);
end

Answer 1

[Walter Roberson]

You cannot set a cell array entry to a logical value.

>> bar = cell(3,1)
bar = 
     []
     []
     []
>> bar(1) = false
??? Conversion to cell from logical is not possible.

In your code, there is no point using temp_allzeros as an array since every member is the same. Your code could be replaced with

allzeros = cell(size(config.MIDlist,1),1);
for i = 1:length(temp_allzeros)
  allzeros{i} = false;
end

But faster would be

allzeros(1:size(config.MIDlist,1)) = {false};  %corrected per Sean

Note, though, that in your original code and in my code, the cell entries are set to actual logicals, not the empty logical. So you need to jigger the code more:

allzeros(1:size(config.MIDlist,1)) = {false(0,0)};

As you asked about "faster", you might want to do timing tests to compare

[allzeros{1:size(config.MIDlist,1)}] = deal(false(0,0));

[Sean de Wolski]

clear alz

alz(1:5) = {false}

[Walter Roberson]

Corrected in my code, thanks. Note thought that that gives an actual 1x1 logical value, not an empty logical.