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Looping until threshold is met

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I need to create a loop to calculate average temperature using simpsons 1/3rd rule and matlab intergral2 function and determine the minimum number of points (for both x and y values) required for simpsons 1/3rd to acheive an absolute error less the threshold error

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Accepted Answer

Mathieu NOE
Mathieu NOE on 20 Jan 2021
hello
yes - error is not initialized , and BTW, you are shadowing a native matlab function error , which is not good pratice (could led to conflicts or wrong output)
also , your while loop will never stop because the error is constant !
the output of your function is always 24
you can put a breakpoint where you compute I = h/3*(y(1) +even_sum + odd_sum + y(end));
even though each individual term on the RHS is evolving , the result remains exactly the same.
I checked the code of your 1/3 simpson rule and it's correct IMHO
in other words , you have demonstrated that doing this integral computation with always refined x vector does not change the integral value

More Answers (1)

KALYAN ACHARJYA
KALYAN ACHARJYA on 20 Jan 2021
You have to initialize "error" before the loop. The initial value must be less than a threshold value as defined. Also make sure that the error value is continuously increasing as the iteration progress, so that it definitely break loop condition.

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Nilakshi Manawadu
Nilakshi Manawadu on 20 Jan 2021
Thanks Kalyan! I've initalized the error as you've suggested. How would you go about making sure that the error value is continuously increasing as the iteration progress?
KALYAN ACHARJYA
KALYAN ACHARJYA on 20 Jan 2021
Just make sure it will, otherwise, while loop runs continuously. You may check the code with sample 2/3 iteration manually.
error=abs(av_temp_simp13(iter)-av_temp_matlab);

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