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Minimum value with row index

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Mohammad Yunus Ali
Mohammad Yunus Ali el 29 de Mzo. de 2011
I wrote the following code to get a minimum positive value and the row index as well but the output is giving wrong row index. Anyone can help me?
The answer should be...minba=0.005 ri=9
clc; clear all;
ba=[52 15 52 44 44 0 -25 -4 .05]; [minba ri]=min(ba((ba>0)))

Respuesta aceptada

Sean de Wolski
Sean de Wolski el 29 de Mzo. de 2011
idx = min(find(ba==minba))
  2 comentarios
Walter Roberson
Walter Roberson el 29 de Mzo. de 2011
idx = find(ba==minba,1);
Matt Fig
Matt Fig el 29 de Mzo. de 2011
I understand the question to be "How do I find the minba and ri," not, "Given, minba, how to find the ri?"

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Más respuestas (2)

Matt Fig
Matt Fig el 29 de Mzo. de 2011
If minba is not known before hand (the general case, and what it sounds like you want to have), then:
ba = [52 15 52 44 44 0 -25 -4 .05]; % Your data...
ba(ba<=0) = inf; % Take non-positive values out of the picture.
[minba,ri] = min(ba) % Find the min and index.
minba =
0.05
ri =
9
A faster alternative to the above, if the number of non-positives is a large fraction of the whole:
minba = min(ba((ba>0)));
ri = find(ba==minba,1);
  3 comentarios
Matt Fig
Matt Fig el 29 de Mzo. de 2011
How would you use FIND if minba wasn't known before hand? I think anything that could do this using FIND would be slower than what I showed...
Matt Fig
Matt Fig el 29 de Mzo. de 2011
But I was wrong. This is faster indeed, when the number of non-positives is a large fraction of the whole:
minba = min(ba((ba>0)));
ri = find(ba==minba,1);

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Walter Roberson
Walter Roberson el 29 de Mzo. de 2011
idx = find(ba > 0,1);
minba = ba(idx);
  5 comentarios
Sean de Wolski
Sean de Wolski el 29 de Mzo. de 2011
Congrats Walter on your 1000th answer!
Matt Fig
Matt Fig el 29 de Mzo. de 2011
@Walter
Qouting the OP (without quotes of course)
I wrote the following code to ...
The answer _should_ _be_...minba=0.005 ri=9
So I assume Mohammad wanted to be shown the _correct_ way to get both minba and ri.

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