Effacer les filtres
Effacer les filtres

Help me find the index value for first minimum value in a matrix.

9 vues (au cours des 30 derniers jours)
Divya Ganesan
Divya Ganesan le 29 Mar 2021
I have a matrix
A=[ 34 67 78 88 4 15 23 67 78 56 3 2 24 67]
First minimum value in this matrix is 4. (this is first drop). Index of 4 is 5.
After 4 many minimum value is there (i.e) 2.
I don't want to consider the other minimum value 2.
I want index of first minimum value (i.e first drop) as a output...
output =( first minimum value 4 and its index is 5)
someone please suggest me a code to solve this..

Réponse acceptée

Walter Roberson
Walter Roberson le 29 Mar 2021
A=[ 34 67 78 88 4 15 23 67 78 56 3 2 24 67]
A = 1×14
34 67 78 88 4 15 23 67 78 56 3 2 24 67
find(diff(A) < 0, 1)
ans = 4

Plus de réponses (2)

Bruno Luong
Bruno Luong le 29 Mar 2021
[~,idx] = min(A)
  5 commentaires
Walter Roberson
Walter Roberson le 29 Mar 2021
OP stands for "Original Poster"
Bruno Luong
Bruno Luong le 29 Mar 2021
Not sure your definition of "first drop", but try this
d=diff(A);
find(d(1:end-1)<=0 & d(2:end)>=0,1,'first')+1

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Riley
Riley le 29 Mar 2021
Modifié(e) : Riley le 29 Mar 2021
A=[ 34 67 78 88 4 15 23 67 78 56 3 2 24 67];
flag=0;
for i=1:length(A)-1
if flag==0&&A(i+1)<A(i)
flag=1;
continue;
end
if flag==1&&A(i)<A(i+1)
first_min=A(i);
idx=i;
break;
else
flag=0;
end
end
first_min
idx
Hi, OP means original poster which is you here. The code above can find the first minimum value and its indice, only if 4 is the first drop. As you can see, if the number ahead of 4 is smaller than 88, this code fails. This is not the perfect solution. Hope you can find a better one.

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