Accessing empty array element through a loop
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I have following program
r = 0;
syms x y z
Base = x*y*z;
for j = 1:8
r = r+1;
X(r) = j;
x = X(r);
AN = eval(Base);
Base1(r) = AN;
end
First_Int = (Base1(1,1)+ 4*Base1(1,2)+ 2*Base1(1,3) + 4*Base1(1,4)+ 2*Base1(1,5)+ 4*Base1(1,6)+ 2*Base1(1,7)+ 4*Base1(1,8)+Base1(1,9))/(3);
It is clear that array size is increasing dynamically and consume much time. There will be two other loops for y and z to complete the calculation with values.
Can I have an alternative way of doing this to save time and memory?
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回答(1 个)
Geoff Hayes
2016-2-21
Harsha - I'm not clear on how your question title accessing empty array element relates to your code. Where are you trying to access an empty element?
If you are concerned with the array size increasing dynamically on each iteration of the loop, then pre-allocate or size the array before entering the loop as
n = 8;
X = zeros(n,1);
Base1 = zeros(n,1);
for k=1:n
X(k) = k;
Base1(k) = k*y*z;
end
It may be that you need to show your outer loops where y and z are initialized. Note how in the above, I have removed the need for the indexing variable r as k can do the same. I use k as MATLAB uses i and j to represent the imaginary number.
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Geoff Hayes
2016-2-23
编辑:Geoff Hayes
2016-2-23
Harsha - what is Base1 supposed to be? An array of symbols or scalar values? I don't understand why your are using symbols for xi, xj, yi, yj, zi and zj.
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