Reverse 2D-lookup table: issues iterating through loops

18 views (last 30 days)
Hi,
I am trying to implement a reverse 2d-lookup table as described in this thread:
The accepted answer provides this code for finding an input B1 at a specified A1 and C1 input:
A=[17.9 18.0 18.1 18.2]';
B=[0.4 0.5 0.6 0.7];
C=[67 89 95 108
74 92 110 123
80 97 115 127
84 106 119 135];
A1=18.046;
%Z=interp2(A,B,C,A1,B);
Z=interp2(A,B,C',A1,B);
C1=105;
B1=interp1(Z,B,C1);
I am trying to do a similar thing with inputs p,d, trying to get output s which I have stored in the variable so
[P,S] = meshgrid(54020:100:101320,0:10:3000);
d = -100.*(((((1373.393./4.002602).*8.3144598).*300)./((P+S).*0.4569)).*((log(P./(P+S)))-(P./(P+S))+1));
so = zeros(301, 474);
p = 54020:100:101320;
p = p';
s = 0:10:3000;
for i = 1: size(p)
%Z=interp2(A,B,C,A1,B);
Z=interp2(p,s,d,p(i),s);
for j = 1:size(s) -1
so(i,j)=interp1(Z,s,d(i,j));
end
end
I initialized the so variable as a matrix of zeros in the start to avoid a warning saying the size of so will be increasing throughout the iteration of the loops.
However, when running this code, so remains unpopulated and remains as a matrix of zeros
I am not sure why this is the case. Any help is much appreciated.

Accepted Answer

Jyotsna Talluri
Jyotsna Talluri on 7 Jul 2020
In your code provided, size of array s is [1 301].
for j = 1:size(s)-1 % first element of the size array is considered
In above line j is empty row vector due to which loop excecution does not take place and hence the array 'so' remains as it is initialized.
Try replacing your code with below lines.
for i = 1:length(p)
%Z=interp2(A,B,C,A1,B);
Z=interp2(p,s,d,p(i),s);
for j = 1:length(s)
so(i,j)=interp1(Z,s,d(j,i));
end
end

More Answers (0)

Categories

Find more on Loops and Conditional Statements in Help Center and File Exchange

Tags

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!