Simpson's rule in numerical methods











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1
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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
























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















up vote
1
down vote

favorite












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
























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













up vote
1
down vote

favorite









up vote
1
down vote

favorite











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















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 at 0:47









Bernard

117k637109




117k637109










asked Dec 4 at 0:46









fr14

38318




38318












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


















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
















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




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










1 Answer
1






active

oldest

votes

















up vote
1
down vote



accepted










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





















  • thanks for the submission! I see where I went wrng
    – fr14
    Dec 4 at 1:06






  • 1




    @fr14 Happy to help
    – caverac
    Dec 4 at 1:06










  • I have posted another question using gauss quadrature
    – fr14
    Dec 4 at 1:47











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1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes








up vote
1
down vote



accepted










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





















  • thanks for the submission! I see where I went wrng
    – fr14
    Dec 4 at 1:06






  • 1




    @fr14 Happy to help
    – caverac
    Dec 4 at 1:06










  • I have posted another question using gauss quadrature
    – fr14
    Dec 4 at 1:47















up vote
1
down vote



accepted










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





















  • thanks for the submission! I see where I went wrng
    – fr14
    Dec 4 at 1:06






  • 1




    @fr14 Happy to help
    – caverac
    Dec 4 at 1:06










  • I have posted another question using gauss quadrature
    – fr14
    Dec 4 at 1:47













up vote
1
down vote



accepted







up vote
1
down vote



accepted






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












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 at 1:00









caverac

12.6k21027




12.6k21027












  • thanks for the submission! I see where I went wrng
    – fr14
    Dec 4 at 1:06






  • 1




    @fr14 Happy to help
    – caverac
    Dec 4 at 1:06










  • I have posted another question using gauss quadrature
    – fr14
    Dec 4 at 1:47


















  • thanks for the submission! I see where I went wrng
    – fr14
    Dec 4 at 1:06






  • 1




    @fr14 Happy to help
    – caverac
    Dec 4 at 1:06










  • I have posted another question using gauss quadrature
    – fr14
    Dec 4 at 1:47
















thanks for the submission! I see where I went wrng
– fr14
Dec 4 at 1:06




thanks for the submission! I see where I went wrng
– fr14
Dec 4 at 1:06




1




1




@fr14 Happy to help
– caverac
Dec 4 at 1:06




@fr14 Happy to help
– caverac
Dec 4 at 1:06












I have posted another question using gauss quadrature
– fr14
Dec 4 at 1:47




I have posted another question using gauss quadrature
– fr14
Dec 4 at 1:47


















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