How Can I replace function 'strcat'

How can I replace 'strcat' function in the code below Manually so that it will work same as the function and the output of the code will be the same.

thanks

      prob_dist = [32 17 9 9 18 42 10 5 1 2 3 21 23 13 13 26 56 16 15 14 7 4 3];
      sorted_prob = prob_dist;
          rear = 1;
          y=length(prob_dist);
      while (length(sorted_prob) > 1)
        % Sort probs
          %[sorted_prob,indeces] = sort(sorted_prob,'ascend');
          initialFrequencyList = sorted_prob
       %   clear initialFrequencyIndex
      initialFrequencyIndex = 1:length(sorted_prob)
      N = length(initialFrequencyList);
      for nodes = 1:N
          for nodes2 = (nodes + 1):N
              if initialFrequencyList(nodes) > initialFrequencyList(nodes2)
                  temporaryFrequency = initialFrequencyList(nodes);
                  initialFrequencyList(nodes) = initialFrequencyList(nodes2);
                  initialFrequencyList(nodes2) = temporaryFrequency;
                  temporaryIndex = initialFrequencyIndex(nodes);
                  initialFrequencyIndex(nodes) = initialFrequencyIndex(nodes2);
                  initialFrequencyIndex(nodes2) = temporaryIndex;
              end
          end
      end
      sorted_prob = initialFrequencyList
      indeces = initialFrequencyIndex
         % Sort string based on indeces
        sorted_str = sorted_str(indeces);
        % Create new symbol
        new_node = strcat(sorted_str(2),sorted_str(1)); %strcat
        new_prob = sum(sorted_prob(1:2));
        % Dequeue used symbols from "old" queue
        sorted_str =  sorted_str(3:length(sorted_str));
        sorted_prob = sorted_prob(3:length(sorted_prob));
        % Add new symbol back to "old" queue
        sorted_str = [sorted_str, new_node];
        sorted_prob = [sorted_prob, new_prob];
        % Add new symbol to "new" queue
        newq_str(rear) = new_node; %no square bracket
        newq_prob(rear) = new_prob;
        rear = rear + 1;
      end
      indeces
      %%Form Huffman Tree Data
      % Get all elements for the tree (symbols and probabilities) by concatenating
      % the original set of symbols with the new combined symbols and probabilities
      tree = [newq_str,init_str];
      tree_prob = [newq_prob, init_prob];
      % Sort all tree elements
      [sorted_tree_prob,indeces] = sort(tree_prob,'descend');
       sorted_tree = tree(indeces);
      %%Calculate Tree Parameters
      % Calculate parent relationships for all tree elements.
      % This will allow the treeplot command to realize the correct tree structure.
      parent(1) = 0;
      num_children = 2;
      for i = 2:length(sorted_tree)
        % Extract my symbol
        me = sorted_tree{i};
        % Find my parent's symbol (search until shortest match is found)
        count = 1;
        parent_maybe = sorted_tree{i-count};
        diff = strfind(parent_maybe,me); %strfind
                     while (isempty(diff))
                       count = count + 1;
                       parent_maybe = sorted_tree{i-count};
                       diff = strfind(parent_maybe,me);%strfind
                     end
        parent(i) = i - count;
      end

[Jiro Doke]

Can you explain why you need to do this?

[Tadele Gerem]

Dear Jiro,

I want to change the matlab code to VHDL using accelDSP but 'strcat' is not synthesizable in accelDSP.

[Walter Roberson]

So what happened when you converted the code to use [] like I showed in the other discussion?

Answer 1

[Walter Roberson]

You would do it the same way as we discussed before.

[Tadele Gerem]

Dear Walter,

yes I have tried as we discussed before and two of your suggestions work perfectly.

strcat(w,code{i}) ---> [w, code{i}];

and display([my_str(i), ' --> ', num2str(prob_dist(i))]);

works perfectly but the rest are not working .

and Now I am left with one 'strcat' and two 'strfind' functions

I have changed the sort function with equivalent coding of Matlab

.And pls help me for that.

thanks

[Walter Roberson]

You did not indicate the data type of sorted_str . If it is a cell array, then

new_node = strcat(sorted_str(2),sorted_str(1))

would become

new_node = [sorted_str{2},sorted_str{1}];

[Tadele Gerem]

Dear Walter ,

the sample output for sorted_str is

sorted_str =

Columns 1 through 22

'z' '.' 'q' 'p' 'b' 'y' 'g' 'h' 'u' 'm' 'l' 't' 'd' 'i' 'c' 'a' 'f' 'n' 'o' 'r' 's' 'e'

Column 23

' '

and I replace

new_node = strcat(sorted_str(2),sorted_str(1))

with

new_node = [sorted_str{2},sorted_str{1}];

and the error is

??? Subscripted assignment dimension mismatch.

Error in ==> huffmanFunction at 118

newq_str(rear) = new_node; %no square bracket

[Walter Roberson]

That's a cell array, alright. Okay, I should have said,

new_node = {[sorted_str{2},sorted_str{1}]};

[Tadele Gerem]

It works perfectly,

And what about the 'strfind' function in the code below pls

count = 1;

parent_maybe = sorted_tree{i-count};

diff = strfind(parent_maybe,me);

while (isempty(diff))

count = count + 1;

parent_maybe = sorted_tree{i-count};

diff = strfind(parent_maybe,me);

end

parent(i) = i - count;

end

thank you so much

[Walter Roberson]

That code doesn't look likely to be correct to me, but that's a matter for another day.

For your purposes:

function pos = strfind(string, pattern)

pos = [];

N = length(pattern) - 1;

for K = 1 : length(string) - N

if all(string(K:K+N) == pattern)

pos = K;

return

end

end

end

[Tadele Gerem]

Dear Walter,

I replaced the code you write as the one below but it doesn't work.

What is my problem?

diff=[];

N = length(me) - 1;

for K = 1 : length(parent_maybe) - N;

if all(parent_maybe(K:K+N) == me)

pos =K;

return

end

end

end

thanks a lot

[Walter Roberson]

The return call is suitable for a function but not for expanding the code in-line. In-line you would use break instead of return, and you would remove the final "end", and you would assign K to diff instead of to pos.

[Tadele Gerem]

Dear Walter,

The syntax works fine,

pos = [];

N = length(me) - 1;

for diff = 1 : length(parent_maybe) - N

if all(string(diff:diff+N) == me)

pos = diff;

break

end

end

But the output is a little unexpected,

> In huffmanFunction at 161

Warning: string is obsolete and will be discontinued.

Use char instead.

ans =

Columns 1 through 12

'' '0' '00' '000' '0000' '00000' '000000' '0000000' '00000000' '000000000' '0000000000' '00000000000'

Columns 13 through 19

'000000000000' '0000000000000' '00000000000000' '000000000000000' '0000000000000000' '00000000000000000' '000000000000000000'

thanks

[Walter Roberson]

It would have been easier if you had simply put my suggest strfind as a function in your file. Anyhow, replace string with parent_maybe (which you had done before and reverted?)

[Tadele Gerem]

Dear Walter ,

Is it possible to replace 'num2str' function with other matlab codes as I found it to be non synthesizable?

Btw,I am very much thankful to your help as it is very valuable to me.

[Walter Roberson]

It is probably possible to replace num2str, but I would need to know the datatypes; if you are printing out anything other than integers then I need to know the format you want to use.

[Tadele Gerem]

Dear Walter,

num2str function is found below in this code of my matlab function. And the sample output is shown below the code.

for i = 1:length(sorted_tree)

% Initialize code

code{i} = '';

% Loop until root is found

index = i;

p = parent(index);

while(p ~= 0)

% Turn weight into code symbol

w = num2str(weight(index))

% Concatenate code symbol

code{i} = [w,code{i}]; %%strcat

% Continue towards root

index = parent(index);

p = parent(index);

end

end

codeBook = [sorted_tree', code']

w =

0

w =

1

w =

0

w =

0

w =

1

w =

0

[Walter Roberson]

Then the first thing to try is replacing num2str(X) by sprintf('%d',X)

[Tadele Gerem]

Dear Walter,

The function 'sprintf' is also not synthesizable

[Walter Roberson]

See this for code:

http://www.mathworks.com/matlabcentral/answers/1804-ascii-string-with-sci-transmit#answer_2706