i have a matrix and check for a column to see if the values are rapidly decreasing in steps of five. how to check for it? for example the matrix is x and the second column.
MATLAB: Check for decrease and increase
decrease
Related Solutions
char(feval(symengine, 'op', eqn1, 1))The defined relationship operators are _equal, _unequal, _approx, _less, and _leequal . A>B is rewritten as _less(B,A) and A>=B is rewritten as _leequal(B,A)
Hi,
basically there are two ways described there:
1- triangle thresholding
2- local maxima of curvature
i prefer the first one as i think it directly answer your question (the second one is for more spesific tasks)
% here is a small code to help you start
% Lets say your data are defined in (x,y) values
% then do the following
time = x;% here you should enter your data name
data = y;% here you should enter your data name% Basically it draws a line from the peak to the tail and then draws
% perpendicular lines from that hypotenuse line to the curve.
% The longest (smollest) perpendicular line from the hypotenuse to the curve
% indicates the "corner" of the curve. Maybe that will work for you. (this discribtion was taken from the reference before)
% Two endpoints on the curve "data"
x = [time(1) time(end)];y = [data(1) data(end)];% The slope of the line connecting the two endpoints
m = ( y(2) - y(1) )/( x(2) - x(1) );pm= - 1 / m;figure();hold allhP = plot(time,data,'b',x,y,'g',x(1),y(1), 'ro');grid onyl = ( (m * time) + (m^2 * data) - (m * x(1)) + y(1) )/(1+m^2);xl = T1 - m*(yl - data);d2 = (xl - time).^2 + (yl - data).^2;perpDist = d2;[val_max, idx_max] = max(perpDist);[val_min, idx_min] = min(perpDist(2:end-1));[val_maxL, idx_maxL] = max(perpDist(1:idx_min));plot(time,data,'b',time(idx_max),data(idx_max),'ro',time(idx_min),data(idx_min),'ro',time(idx_maxL),data(idx_maxL),'ro');grid on;hold all; plot(time,perpDist); hold offI hope this answer your question (how accurate the point will depend on your massy data)
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