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











Your Answer





StackExchange.ifUsing("editor", function () {
return StackExchange.using("mathjaxEditing", function () {
StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
});
});
}, "mathjax-editing");

StackExchange.ready(function() {
var channelOptions = {
tags: "".split(" "),
id: "69"
};
initTagRenderer("".split(" "), "".split(" "), channelOptions);

StackExchange.using("externalEditor", function() {
// Have to fire editor after snippets, if snippets enabled
if (StackExchange.settings.snippets.snippetsEnabled) {
StackExchange.using("snippets", function() {
createEditor();
});
}
else {
createEditor();
}
});

function createEditor() {
StackExchange.prepareEditor({
heartbeatType: 'answer',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
noCode: true, onDemand: true,
discardSelector: ".discard-answer"
,immediatelyShowMarkdownHelp:true
});


}
});














draft saved

draft discarded


















StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3024948%2fsimpsons-rule-in-numerical-methods%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























1 Answer
1






active

oldest

votes








1 Answer
1






active

oldest

votes









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


















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3024948%2fsimpsons-rule-in-numerical-methods%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Ellipse (mathématiques)

Quarter-circle Tiles

Mont Emei