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POFind maximum in an interval of a vector
 

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  1. POFind maximum in an interval of a vector
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    <p>I want to find the value and the position of the maximum in an interval 1 and the maximum in interval 2 in a vector (as depicted on the example figure). The borders of the interval 1 and 2 are given.</p> <p><img src="https://i.stack.imgur.com/PIdKD.png" alt="example"></p> <p>NEW VERSION - CODE MORE REUSEABLE</p> <p>Uses only one interval as Dennis Jaheruddin suggested and is written as a function.</p> <pre><code>function test %% Test data x=0:0.1:10-0.1; x_total=0:0.1:20-0.1; y=-(x-5.8).^2+25; y_total=[y,y+10]; figure(1); plot(x_total,y_total); grid on; interval=[12,18]; [maxValue,maxValuePositon] = findMaxInInterval(x_total,y_total,interval) [maxValue,maxValuePositon] = findMaxInInterval2(x_total,y_total,interval) end %% Algorithm function [maxValue,maxValuePositon] = findMaxInInterval(x,y,interval) index = x&gt;=interval(1) &amp; x &lt;= interval(2); offset = find(index == 1,1,'first') -1; [maxValue,indexMax] = max(y(index)); maxValuePositon = x(indexMax+offset); end %% Algorithm - Alternative function [maxValue,maxValuePositon] = findMaxInInterval2(x,y,interval) index = x&gt;=interval(1) &amp; x &lt;= interval(2); y_temp = y(index); x_temp = x(index); [maxValue,indexMax] = max(y_temp); maxValuePositon = x_temp(indexMax); end </code></pre> <p>THIS IS THE OLD VERSION</p> <p>I have a solution but my code seems pretty complicated to me. Has someone solution more straight forward (or simply the right MATLAB-function?). This is my solution so far:</p> <pre><code>%Generate test function x=0:0.1:10-0.1; x_total=0:0.1:20-0.1; y=-(x-5).^2+25; y_total=[y,y+10]; figure(1); plot(x_total,y_total); grid on; interval1=[2,8]; interval2=[12,18]; %Algorithm index1 = x_total&gt;=interval1(1) &amp; x_total &lt;= interval1(2); index2 = x_total&gt;=interval2(1) &amp; x_total &lt;= interval2(2); offset1 = find(index1 == 1,1,'first') -1; offset2 = find(index2 == 1,1,'first') -1; disp('Maximum 1 and 2:'); [max1,indexMax1] = max(y_total(index1)) [max2,indexMax2] = max(y_total(index2)) disp('Position of Maximum 1 and 2:'); x_total(indexMax1+offset1) x_total(indexMax2+offset2) </code></pre>
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    1. USSemjon Mössinger
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    1. COThat function looks good to me. I doubt you can make it any simpler.
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    2. COLooks ok, but if you want to do this for more than 2 intervals you definitely want to prevent code duplication per interval.
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      1. USDennis Jaheruddin
 

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