getting min and max for different y-values of a graph

x = -10:0.1:10;

f1 = trapmf(x,[-2 0 0 2]);

I need to find min(x),max(x) for 201 different f1 values

since my f1 ranges from 0 to 1 in this built in function

@ f1 = 0, I need a min(x), max(x)

@ f1 = 0.05, min(x), max(x)

..

all the way upto

@f1 = 1, min(x), max(x).

Answer 1

[Walter Roberson]

testlocs = 0:0.05:1;
t = bsxfun(@ge, f1(:), testlocs);

for K = 1 : size(t, 1)
  minidx = find(t(K,:), 1, 'first');
  maxidx = find(t(K,:), 1, 'last');
  minx(K) = testlocs(minidx);
  maxx(K) = testlocs(maxidx);
end

[soloby]

i'm sorry I dont follow your coding, what is minx? it gives me a 1x201 matrix with all 0's.

[Walter Roberson]

testlocs = 0:0.05:1;
t = bsxfun(@le, testlocs(:), f1(:)');

for K = 1 : size(t, 1)
  minidx = find(t(K,:), 1, 'first');
  maxidx = find(t(K,:), 1, 'last');
  minx(K) = testlocs(minidx);
  maxx(K) = testlocs(maxidx);
end