unclear number of if or maybe other commands?!

Hello

I am confused in writing a code which i am going to explain. imagine there is a row matrix whose dimension is not clear (as in each iteration there may be more arrays in this row vector), e.g. ccc=[10 20 30 40 50 ...]. On the other hand, there is a matrix (called Length(i)) that measures the length of some segments along a curve with respect to an origin. There is a length critteria called:J.

if Length(i)<J then assign ccc1 to that segment

if Length(i)>J or Length(i)<2*J then assign ccc2 to the second segment

if Length(i)>2*J or Length(i)<3*J then assign ccc3 to the third segment

.

.

.

It is worthy to point that Length(i)<J represents segment 1, J<Length(i)<2*J represents segment 2, etc..

it is not clear how many segments and c matrix arrays we would have.. Any recommendation/idea is highly appreciated.

A draft of my code is attached below:

%   for i=1:n  % n is the number of segments
%      Length(i)=sqrt(abs((H(i,1)-PP(1,1))^2+((H(i,3)-PP(1,2))^2)));
%      
%             if Length(i)<J  %for 2 segments,,,what if there are more than 2 segments
%                 
%             C(g,i)= CCC(g,1);  
%             
%             elseif Length(i)>J && Length(i)<2*J

%                 C(g,i)=CCC(g,2);
%             
%             end
%               
%   end
% end

Best Regards

[Walter Roberson]

while Length(i)>J or Length(i)<2*J then assign c2 to the second segment

You could use

    segment_index = c( max(1, ceil(Length / J)) )

This might, however, differ for the case where the Length entry is an exact multiple of J... which is a case your while does not handle.

[Pooneh Shah Malekpoor]

Hello Walter,, thanks for this, however, sorry as I have editted my question as you can see .In fact, I have replaced while with if. How can i define an if condition for the above code such that it continues running for all of the segments(whose number is not clear)?

and what do you mean by max(1, ceil(Length / J)) here?

[Walter Roberson]

In the original form of your question, we could not guarantee that the Length entries were non-negative, so we could not guarantee that ceil(Length / J) would be > 0 . In such a situation then under the definition "if Length(i)<J then assign ccc1" we need to assign the first segment. Rather than testing for negative and using 1 in that case, we can use max(1,value) which will be 1 if value <= 1 and will be the value otherwise.

In the revised form we can see that the Length is a euclidean distance. Euclidean distances can potentially be 0, so we run into the same problem that Length/J might be 0, and ceil(0) is 0. Rather than testing for that case, we can use the max() as before.

[Pooneh Shah Malekpoor]

Thank you so much, it is working now...I used the idea you gave me on ceil..

i=1:n

Length(i)=sqrt(abs((H(i,1)-PP(1,1)).^2+((H(i,3)-PP(1,2)).^2)));

z(i)=ceil(Lengthl(i)/J);

C(g,i) = CCC( g, z(i));

Answer 1

[Steven Lord]

So you want to discretize your data?

x = rand(10, 1);
binedges = 0:0.25:1;
values = [1.1, 2.22, 3.333, 4.4444];
d = discretize(x, binedges, values);
results = table(x, d, 'VariableNames', ["x", "corresponding values"])

results = 10×2 table
        x        corresponding values
    _________    ____________________

      0.37963             2.22       
      0.44234             2.22       
      0.29959             2.22       
      0.88397           4.4444       
     0.061985              1.1       
      0.78041           4.4444       
    0.0083851              1.1       
       0.6224            3.333       
      0.66319            3.333       
      0.45249             2.22       

[Pooneh Shah Malekpoor]

Thanks Steven!