finding minimum value of certain row of matrix with condition

i have matrix [6,6], how to find minimum value at certain row eg what is the minimum value that >0, at row 1?

r=[0.00   18.68  39.62  20.81   5.39  39.92
18.68    0.00  33.84  38.91  24.04  53.41
39.62   33.84   0.00  48.38  42.20  45.12
20.81   38.91  48.38   0.00  15.62  25.08
 5.39   24.04  42.20  15.62   0.00  36.40
39.92   53.41  45.12  25.08  36.40   0.00];

Then the result is 5.39 in [1 5], it will loop to continued to find the min value at other row, the next row searching on the min value is based on the previous result of the column. eg 2nd result is 15.62 [5 4]

[Mohammad Abouali]

what would be the third result? you jumped from row 1 to row 5. The result in row one was 5.39 and the first element in row 5 is 5.39. But now the result is 15.62 but there is no row with 15.62 as the first value. so what would be the third result? or do you stop here.

[nadhirah]

no, it should be loop till complete all the 6 points. i think i should put the others condition such as only visited once and end with point 1 and each point only visited once.

Answer 1

[Image Analyst]

If I understood you correctly, try this:

clc;
workspace;
fontSize = 25;
close all;
r=[0.00   18.68  39.62  20.81   5.39  39.92
18.68    0.00  33.84  38.91  24.04  53.41
39.62   33.84   0.00  48.38  42.20  45.12
20.81   38.91  48.38   0.00  15.62  25.08
 5.39   24.04  42.20  15.62   0.00  36.40
39.92   53.41  45.12  25.08  36.40   0.00];

[rows, columns] = size(r)
thisMin = -1*ones(rows, 1);
priorRowMin = 0;
for row = 1 : rows
  % Get this row all by itself.
  thisRow = r(row, :);
  % Remove values less than or equal to the prior row's min
  % because we only want to consider values above the prior row's min.
  thisRow(thisRow <= priorRowMin) = [];
  if ~isempty(thisRow)
    % If there are any values left...
    % Find the min of what's left.
    thisMin(row) = min(thisRow);
    % Update the prior row min:
    priorRowMin = thisMin(row);
  end
end
thisMin

In the command window:

thisMin =
                      5.39
                     18.68
                     33.84
                     38.91
                      42.2
                     45.12

[nadhirah]

may i know how can i display the current coordinate of the min point, such as 5.39 coordinate is [1 5].

[Image Analyst]

Before the loop do

locations = -1*ones(rows, 2);

Inside the if, do

[thisMin(row), columnOfMin] = min(thisRow);
locations(row, 1) = row;  % Save row
locations(row, 2) = columnOfMin; % Save column.

Answer 2

[Sean de Wolski]

Replace the zeros with Infs and take the min:

r2 = r;
r2(r2==0) = inf;
min(r2,[],2)