Need Help for creating constraint with If conditions
1 view (last 30 days)
Show older comments
I have 'Z(im)', 't(m)', and f(i) vectors as following (left side is parameter indices=Zim):
im Zim t(m) f(i)
11 0 12 6
12 0 11 6
13 1 10 6
21 0 12 3
22 1 11 3
23 0 10 3
31 0 12 5
32 1 11 5
33 0 10 5
and an equality constraint as following:
Z(im)*Y(im)+S(im)=t(m)-Z(im)*f(i) for all i and m, *IF Zim=1*
I need to find Rhs of equalities for values where Zim=1.
For instance, we know Z13, Z22, and Z32 are all equal to 1. Thus I want to create a 3x1 (mx1) column vector for those right hand side values as following:
b=[4; 8; 6]
I believe, I need to use for loop and if command. But, I can't figure out a way to construct a loop for this question.
Thanks for help.
0 Comments
Accepted Answer
dpb
on 9 Jul 2016
No loops needed...given your above array as m,
>> ix=m(:,2)==1;
>> b=m(ix,3)-m(ix,4)
b =
4
8
6
>>
8 Comments
dpb
on 10 Jul 2016
Edited: dpb
on 11 Jul 2016
"For Spos and Ypos, you could say: Spos = i*m; Ypos = 2*i*m; because i=3 and m=3"
No. The general expression for the row location from 1 thru 9 for the 3x3 array locations is (m-1)+3(i-1)+1.
>> a=reshape(1:9,3,3) % a 3x3 array in memory order
a =
1 4 7
2 5 8
3 6 9
>> [i j]=ind2sub(size(a),1:9); % the subscripts from linear order
>> [i.' j.']
ans =
1 1
2 1
3 1
1 2
2 2
3 2
1 3
2 3
3 3
>> for i=1:3, % from explicit expression
for m=1:3,
disp([m i (m-1)+3*(i-1)+1]),
end,end
1 1 1
2 1 2
3 1 3
1 2 4
2 2 5
3 2 6
1 3 7
2 3 8
3 3 9
>>
The locations you're wanting in the 18-column array are simply two 9-column array locations placed one to the right of the other. Since each has the same i,m values, they're simply offset by 10 positions from each other; no reason to compute but the left one and then shift it to the right to compute the other.
More Answers (0)
See Also
Categories
Find more on Matrix Indexing in Help Center and File Exchange
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!