How can I detect number that does not follow an increasing order?

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Sandy
Sandy 2014-6-24
编辑： Joseph Cheng 2014-6-24
I have a vector like this:
  • 1 2 3 4 100 5 6 7
or it could also be like this:
  • 153 158 161 163 172 123 179 181
if I look at the vector, I know I should delete 100 in 1st one and 123 in 2nd one. After that, either vector is in an increasing order.
I tried to use code diff(vector) to solve the problem in Matlab.
For 1st vector, the difference: 1 1 1 96 -95 1 1. The negative appears at 5th and I should delete No.5 in original sample.
For 2nd vector, the difference: 5 3 2 9 -49 56 2. The negative appears at 5th but I should delete No.6 in original sample.
The code diff cannot handle both cases at the same time. I am wondering if there is a more effective way.
Thank you very much!
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Joseph Cheng
Joseph Cheng 2014-6-24
编辑：Joseph Cheng 2014-6-24
perhaps some peak detection. performing the convolution of the pattern will lineup max of the convolution with the point that you want to take out. (works with b as well) [a;0 conv(a,[-.5 1 -.5],'valid') 0]
1.0000 2.0000 3.0000 4.0000 100.0000 5.0000 6.0000 7.0000
0 0 0 47.5000 95.5000 48.0000 0 0
and for b
153.0000 158.0000 161.0000 163.0000 172.0000 123.0000 179.0000 181.0000
0 1.0000 0.5000 3.5000 29.0000 52.5000 27.0000 0
might not work for all cases, more sophisticated methods for finding local maximum and local minimum may be what you are looking for.

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Azzi Abdelmalek
Azzi Abdelmalek 2014-6-24
s=[153 158 161 163 172 123 179 181 4 5 190]
while any(diff(s)<0)
ii=[1==0 diff(s)<0]
s(ii)=[];
end
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