How can i count how many function was executed in this code? - matlab

Question

I have been studying Matlab for hobby.
This is my second question in stack-overflow.
These days I have interest in Sudoku by Matlab.
I got code from internet and I am studying this code for 3 weeks.
I want to add function which indicate how many times 'sub-function(candidates)' executed. -> how many times function works for solution.
I used to use cnt = 0 and cnt=cnt+1 for count(under if statement and while statement)
but i realize this code's structure is loop(??)
*i tried it but cnt were reset when i try, i think i know the reason of reset
but i can't write it code
Thank you for your help
function X = s2(X)
% SUDOKU Solve Sudoku using recursive backtracking.
% sudoku(X), expects a 9-by-9 array X.
% Fill in all ?singletons?.
% C is a cell array of candidate vectors for each cell.
% s is the first cell, if any, with one candidate.
% e is the first cell, if any, with no candidates.
[C,s,e] = candidates(X);
while ~isempty(s) && isempty(e)
X(s) = C{s};
[C,s,e] = candidates(X);
end
% Return for impossible puzzles.
if ~isempty(e)
return
end
% Recursive backtracking.
if any(X(:) == 0)
Y = X;
z = find(X(:) == 0,1); % The first unfilled cell.
for r = [C{z}] % Iterate over candidates.
X = Y;
X(z) = r; % Insert a tentative value.
X = s2(X); % Recursive call.
if all(X(:) > 0) % Found a solution.
return
end
end
end
% ???????????????
function [C,s,e] = candidates(X)
C = cell(9,9);
tri = #(k) 3*ceil(k/3-1) + (1:3);
for j = 1:9
for i = 1:9
if X(i,j)==0
z = 1:9;
z(nonzeros(X(i,:))) = 0;
z(nonzeros(X(:,j))) = 0;
z(nonzeros(X(tri(i),tri(j)))) = 0;
C{i,j} = nonzeros(z)';
end
end
end
L = cellfun(#length,C); % Number of candidates.
s = find(X==0 & L==1,1);
e = find(X==0 & L==0,1);
end % candidates
end % s2
i used variable X
X=[4 0 0 0 2 0 0 0 0;
0 1 0 3 0 0 5 0 0;
0 0 9 0 0 8 0 6 0;
7 0 0 6 0 0 1 0 0;
0 2 0 0 0 0 0 0 9;
0 0 3 0 0 4 0 0 0;
6 0 0 7 0 0 0 2 0;
0 8 0 0 1 0 0 0 4;
0 0 0 0 0 9 3 0 0];

Answer 1

You could also use a persistent variable, which should retain its value across multiple calls of the function.
For example:
function [ result ] = myfactorial( num )
% using persistent variable based on
% https://www.mathworks.com/help/matlab/ref/persistent.html
persistent numcalls;
if isempty(numcalls)
numcalls = 0;
end
numcalls = numcalls+1;
disp(strcat('numcalls is now: ', int2str(numcalls)));
% factorial function based on
% https://www.quora.com/How-can-I-create-a-factorial-function-in-MATLAB
if num > 1
result = myfactorial(num-1)*num;
else
result = 1;
end
end
Now call the function.
clear all;
result = myfactorial(5);
The output is:
numcalls is now:1
numcalls is now:2
numcalls is now:3
numcalls is now:4
numcalls is now:5