How to find the descending index in each row of a matrix?

Hi there, I have data for about 2000 lakes through 11 days so I have a 2000x11 matrix. which I want to know for each lake (row) when the numbers become descending. Lets say my matrix is A ( it shows the first four rows of my matrix) and A is:

[26  26  25  25  25  25  25  25  25  6  3;
558  558  558  558  533  521  494  367  367  64  8;
214  212  210  210  182  156  106  73  73  41  9;
448  448  445  445  375  219  132  130  130  73  32]

Finally I want an index vector (2000x1) that shows me the index of the descending point for each row. Means I want my result for the example matrix A to be like matrix below:

3
5
2
3

Any idea is really appreciated.

[David Fletcher]

Could use diff to find the difference between adjacent elements and note where the result goes negative.

[jonas]

Not the most elegant solution but it gets the job done:

[nrow ncol]=size(A)

B=diff(A');

[row col]=find(B<0)

for i=1:nrow

ind(i)=row(min(find(col==i)))+1

end

[Marmar]

This solution works as well. Thank you.

Answer 1

[James Tursa]

E.g., assuming there is always a decrease:

[~,x] = max(diff(A,1,2)<0,[],2);
result = x + 1;

If there is not a decrease, what would you want the code to produce?

[Marmar]

I want 1 for those row, but there is always a decrease.

[Marmar]

That works well. Thank you so much.