Simpson's rule in numerical methods












1












$begingroup$


In the following code I have implemented composite Simpson's rule. However I should be getting approximately $291$ but for some reason I am getting something different. I implemented a few other methods to test it and the proper answer was $291$ So how do I fix my code?



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+h*h)
return s*h/3
print(SimpsonMethod(lambda x: x**2,5,10,100))


giving the output



237.39917687499988









share|cite|improve this question











$endgroup$












  • $begingroup$
    There are related sites in this group of sites for coding Q's.
    $endgroup$
    – DanielWainfleet
    Dec 4 '18 at 2:23
















1












$begingroup$


In the following code I have implemented composite Simpson's rule. However I should be getting approximately $291$ but for some reason I am getting something different. I implemented a few other methods to test it and the proper answer was $291$ So how do I fix my code?



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+h*h)
return s*h/3
print(SimpsonMethod(lambda x: x**2,5,10,100))


giving the output



237.39917687499988









share|cite|improve this question











$endgroup$












  • $begingroup$
    There are related sites in this group of sites for coding Q's.
    $endgroup$
    – DanielWainfleet
    Dec 4 '18 at 2:23














1












1








1





$begingroup$


In the following code I have implemented composite Simpson's rule. However I should be getting approximately $291$ but for some reason I am getting something different. I implemented a few other methods to test it and the proper answer was $291$ So how do I fix my code?



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+h*h)
return s*h/3
print(SimpsonMethod(lambda x: x**2,5,10,100))


giving the output



237.39917687499988









share|cite|improve this question











$endgroup$




In the following code I have implemented composite Simpson's rule. However I should be getting approximately $291$ but for some reason I am getting something different. I implemented a few other methods to test it and the proper answer was $291$ So how do I fix my code?



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+h*h)
return s*h/3
print(SimpsonMethod(lambda x: x**2,5,10,100))


giving the output



237.39917687499988






numerical-methods






share|cite|improve this question















share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Dec 4 '18 at 0:47









Bernard

119k740113




119k740113










asked Dec 4 '18 at 0:46









fr14fr14

38318




38318












  • $begingroup$
    There are related sites in this group of sites for coding Q's.
    $endgroup$
    – DanielWainfleet
    Dec 4 '18 at 2:23


















  • $begingroup$
    There are related sites in this group of sites for coding Q's.
    $endgroup$
    – DanielWainfleet
    Dec 4 '18 at 2:23
















$begingroup$
There are related sites in this group of sites for coding Q's.
$endgroup$
– DanielWainfleet
Dec 4 '18 at 2:23




$begingroup$
There are related sites in this group of sites for coding Q's.
$endgroup$
– DanielWainfleet
Dec 4 '18 at 2:23










1 Answer
1






active

oldest

votes


















1












$begingroup$

Typo in the part of the function that calculates the even nodes, should be s+=2*f(a+i*h), this is after fixing:



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+i*h)
return s*h/3.
print(SimpsonMethod(lambda x: x**2,5,10,100))


and the result



291.66666666666674





share|cite|improve this answer









$endgroup$













  • $begingroup$
    thanks for the submission! I see where I went wrng
    $endgroup$
    – fr14
    Dec 4 '18 at 1:06






  • 1




    $begingroup$
    @fr14 Happy to help
    $endgroup$
    – caverac
    Dec 4 '18 at 1:06










  • $begingroup$
    I have posted another question using gauss quadrature
    $endgroup$
    – fr14
    Dec 4 '18 at 1:47











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1 Answer
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active

oldest

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1 Answer
1






active

oldest

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active

oldest

votes






active

oldest

votes









1












$begingroup$

Typo in the part of the function that calculates the even nodes, should be s+=2*f(a+i*h), this is after fixing:



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+i*h)
return s*h/3.
print(SimpsonMethod(lambda x: x**2,5,10,100))


and the result



291.66666666666674





share|cite|improve this answer









$endgroup$













  • $begingroup$
    thanks for the submission! I see where I went wrng
    $endgroup$
    – fr14
    Dec 4 '18 at 1:06






  • 1




    $begingroup$
    @fr14 Happy to help
    $endgroup$
    – caverac
    Dec 4 '18 at 1:06










  • $begingroup$
    I have posted another question using gauss quadrature
    $endgroup$
    – fr14
    Dec 4 '18 at 1:47
















1












$begingroup$

Typo in the part of the function that calculates the even nodes, should be s+=2*f(a+i*h), this is after fixing:



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+i*h)
return s*h/3.
print(SimpsonMethod(lambda x: x**2,5,10,100))


and the result



291.66666666666674





share|cite|improve this answer









$endgroup$













  • $begingroup$
    thanks for the submission! I see where I went wrng
    $endgroup$
    – fr14
    Dec 4 '18 at 1:06






  • 1




    $begingroup$
    @fr14 Happy to help
    $endgroup$
    – caverac
    Dec 4 '18 at 1:06










  • $begingroup$
    I have posted another question using gauss quadrature
    $endgroup$
    – fr14
    Dec 4 '18 at 1:47














1












1








1





$begingroup$

Typo in the part of the function that calculates the even nodes, should be s+=2*f(a+i*h), this is after fixing:



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+i*h)
return s*h/3.
print(SimpsonMethod(lambda x: x**2,5,10,100))


and the result



291.66666666666674





share|cite|improve this answer









$endgroup$



Typo in the part of the function that calculates the even nodes, should be s+=2*f(a+i*h), this is after fixing:



from math import pi,cos,sin
def SimpsonMethod(f,a,b,n):
h = (b-a)/n
s = f(a)+f(b)
for i in range(1,n,2):
s+=4*f(a+i*h)
for i in range(2,n-1,2):
s+=2*f(a+i*h)
return s*h/3.
print(SimpsonMethod(lambda x: x**2,5,10,100))


and the result



291.66666666666674






share|cite|improve this answer












share|cite|improve this answer



share|cite|improve this answer










answered Dec 4 '18 at 1:00









caveraccaverac

14.4k31130




14.4k31130












  • $begingroup$
    thanks for the submission! I see where I went wrng
    $endgroup$
    – fr14
    Dec 4 '18 at 1:06






  • 1




    $begingroup$
    @fr14 Happy to help
    $endgroup$
    – caverac
    Dec 4 '18 at 1:06










  • $begingroup$
    I have posted another question using gauss quadrature
    $endgroup$
    – fr14
    Dec 4 '18 at 1:47


















  • $begingroup$
    thanks for the submission! I see where I went wrng
    $endgroup$
    – fr14
    Dec 4 '18 at 1:06






  • 1




    $begingroup$
    @fr14 Happy to help
    $endgroup$
    – caverac
    Dec 4 '18 at 1:06










  • $begingroup$
    I have posted another question using gauss quadrature
    $endgroup$
    – fr14
    Dec 4 '18 at 1:47
















$begingroup$
thanks for the submission! I see where I went wrng
$endgroup$
– fr14
Dec 4 '18 at 1:06




$begingroup$
thanks for the submission! I see where I went wrng
$endgroup$
– fr14
Dec 4 '18 at 1:06




1




1




$begingroup$
@fr14 Happy to help
$endgroup$
– caverac
Dec 4 '18 at 1:06




$begingroup$
@fr14 Happy to help
$endgroup$
– caverac
Dec 4 '18 at 1:06












$begingroup$
I have posted another question using gauss quadrature
$endgroup$
– fr14
Dec 4 '18 at 1:47




$begingroup$
I have posted another question using gauss quadrature
$endgroup$
– fr14
Dec 4 '18 at 1:47


















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