Interval overlap not working

Question

Edoardo Modestini 2023-5-3

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1957454-interval-overlap-not-working

评论： Edoardo Modestini 2023-5-27

Hi,

I'm trying to create a Matlab file to carry out pinch analysis. As part of it, I'm checking whether certain streams are present in a temperature interval.

function check_present(obj)
            %Loops through each interval
            for i = 1:length(obj.intervals)
                %Creating "present" and "present names"
                present = [];
                present_names = [];
                for k = 1:length(obj.streams)
                    %Checking if the ranges of the shifted temperatures
                    %overlap with the range of the stream temps, I think.
                    %Clearly, this bit is not working since it outputs the
                    %wrong thing.
                    if overlaps(fixed.Interval(obj.streams(k).Sin, obj.streams(k).Sout), fixed.Interval(obj.intervals(i).Tlow, obj.intervals(i).Thigh, '()'))
                        present = [present; obj.streams(k)];
                        present_names = [present_names; obj.streams(k).name];
                    end
                end
                obj.intervals(i).present = present;
                obj.intervals(i).present_names = present_names;
                

This, however, is not doing what it's meant to, and is outputting the wrong streams in each interval. The matlab files are attached in case not enough information is given here!

Thanks in advance for any help.

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Answer 1

Divyanshu 2023-5-19

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https://ww2.mathworks.cn/matlabcentral/answers/1957454-interval-overlap-not-working#answer_1239624

在 MATLAB Online 中打开

Hi Edoardo,

The reason why your function ‘check_present’ is displaying wrong values is because ‘fixed.Interval()’ function only generates interval when 1st argument passed to this function is lower in range then the 2nd one.

For e.g. -> fixed.Interval(2,8) would produce interval with Left-End ‘2’ & Right-End ‘8’.

But in the case fixed.Interval(7,1) it would produce an empty interval.

And according to the data being used in your scripts there are certain instances where streams like 'Sin' = 390 & 'Sout' = 110 are generated. Hence in such cases function gives wrong output.

Here is a possible workaround to deal with such cases:

function check_present(obj)
    %Loops through each interval
    for i = 1:length(obj.intervals)
        %Creating "present" and "present names"
        present = [];
        present_names = [];
        for k = 1:length(obj.streams)
            leftStr = min(obj.streams(k).Sin,obj.streams(k).Sout);
            rightStr = max(obj.streams(k).Sin,obj.streams(k).Sout);
            streamCur = fixed.Interval(leftStr,rightStr);
            intervalCur = fixed.Interval(obj.intervals(i).Tlow, obj.intervals(i).Thigh,'()');
            if overlaps(streamCur,intervalCur)
                present = [present; obj.streams(k)];
                present_names = [present_names; obj.streams(k).name];
            end
        end
        obj.intervals(i).present = present;
        obj.intervals(i).present_names = present_names;
    end
end