I have a recursion limit error in my quick sort program although I set recursion limit to 1500











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I am trying to write an in-place program that would use the quicksort algorithm to sort a list. But it keeps giving an error:




maximum recursion depth exceeded while calling python object.




Although I tried setting recursion limit.



def partition(L,low,high,comparison):
i=low-1
pivot=random_pivot(L)
for j in range(low,high):
if comparison(L[j],pivot):
i+=1
L[i],L[j]=L[j],L[i]
L[i+1],L[high]=L[high],L[i+1]
return i+1
def inplace_Quicksort(L,low,high,comparison):
low=0
high=len(L)-1
if comparison(low,high):
pivot_index=partition(L,low,high,comparison)
inplace_Quicksort(L,low,pivot_index-1,comparison)
inplace_Quicksort(L,pivot_index+1,high,comparison)
print(L)


Can you please have a look at it and explain to me what is wrong? Thank you so much.










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  • Try to debug your code yourself to see why the code recurses infinitely many times.
    – user202729
    Nov 10 at 16:16






  • 2




    Please be so good to not destroy the constructive edits made by others.
    – trincot
    Nov 10 at 16:16










  • What is random_pivot, and why do the arguments involve no range information?
    – user2357112
    Nov 10 at 16:17















up vote
-1
down vote

favorite












I am trying to write an in-place program that would use the quicksort algorithm to sort a list. But it keeps giving an error:




maximum recursion depth exceeded while calling python object.




Although I tried setting recursion limit.



def partition(L,low,high,comparison):
i=low-1
pivot=random_pivot(L)
for j in range(low,high):
if comparison(L[j],pivot):
i+=1
L[i],L[j]=L[j],L[i]
L[i+1],L[high]=L[high],L[i+1]
return i+1
def inplace_Quicksort(L,low,high,comparison):
low=0
high=len(L)-1
if comparison(low,high):
pivot_index=partition(L,low,high,comparison)
inplace_Quicksort(L,low,pivot_index-1,comparison)
inplace_Quicksort(L,pivot_index+1,high,comparison)
print(L)


Can you please have a look at it and explain to me what is wrong? Thank you so much.










share|improve this question









New contributor




Asmaa Hadir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.




















  • Try to debug your code yourself to see why the code recurses infinitely many times.
    – user202729
    Nov 10 at 16:16






  • 2




    Please be so good to not destroy the constructive edits made by others.
    – trincot
    Nov 10 at 16:16










  • What is random_pivot, and why do the arguments involve no range information?
    – user2357112
    Nov 10 at 16:17













up vote
-1
down vote

favorite









up vote
-1
down vote

favorite











I am trying to write an in-place program that would use the quicksort algorithm to sort a list. But it keeps giving an error:




maximum recursion depth exceeded while calling python object.




Although I tried setting recursion limit.



def partition(L,low,high,comparison):
i=low-1
pivot=random_pivot(L)
for j in range(low,high):
if comparison(L[j],pivot):
i+=1
L[i],L[j]=L[j],L[i]
L[i+1],L[high]=L[high],L[i+1]
return i+1
def inplace_Quicksort(L,low,high,comparison):
low=0
high=len(L)-1
if comparison(low,high):
pivot_index=partition(L,low,high,comparison)
inplace_Quicksort(L,low,pivot_index-1,comparison)
inplace_Quicksort(L,pivot_index+1,high,comparison)
print(L)


Can you please have a look at it and explain to me what is wrong? Thank you so much.










share|improve this question









New contributor




Asmaa Hadir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











I am trying to write an in-place program that would use the quicksort algorithm to sort a list. But it keeps giving an error:




maximum recursion depth exceeded while calling python object.




Although I tried setting recursion limit.



def partition(L,low,high,comparison):
i=low-1
pivot=random_pivot(L)
for j in range(low,high):
if comparison(L[j],pivot):
i+=1
L[i],L[j]=L[j],L[i]
L[i+1],L[high]=L[high],L[i+1]
return i+1
def inplace_Quicksort(L,low,high,comparison):
low=0
high=len(L)-1
if comparison(low,high):
pivot_index=partition(L,low,high,comparison)
inplace_Quicksort(L,low,pivot_index-1,comparison)
inplace_Quicksort(L,pivot_index+1,high,comparison)
print(L)


Can you please have a look at it and explain to me what is wrong? Thank you so much.







python sorting quicksort






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edited Nov 10 at 19:44









Strawberryshrub

705214




705214






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asked Nov 10 at 16:11









Asmaa Hadir

11




11




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New contributor





Asmaa Hadir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






Asmaa Hadir is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












  • Try to debug your code yourself to see why the code recurses infinitely many times.
    – user202729
    Nov 10 at 16:16






  • 2




    Please be so good to not destroy the constructive edits made by others.
    – trincot
    Nov 10 at 16:16










  • What is random_pivot, and why do the arguments involve no range information?
    – user2357112
    Nov 10 at 16:17


















  • Try to debug your code yourself to see why the code recurses infinitely many times.
    – user202729
    Nov 10 at 16:16






  • 2




    Please be so good to not destroy the constructive edits made by others.
    – trincot
    Nov 10 at 16:16










  • What is random_pivot, and why do the arguments involve no range information?
    – user2357112
    Nov 10 at 16:17
















Try to debug your code yourself to see why the code recurses infinitely many times.
– user202729
Nov 10 at 16:16




Try to debug your code yourself to see why the code recurses infinitely many times.
– user202729
Nov 10 at 16:16




2




2




Please be so good to not destroy the constructive edits made by others.
– trincot
Nov 10 at 16:16




Please be so good to not destroy the constructive edits made by others.
– trincot
Nov 10 at 16:16












What is random_pivot, and why do the arguments involve no range information?
– user2357112
Nov 10 at 16:17




What is random_pivot, and why do the arguments involve no range information?
– user2357112
Nov 10 at 16:17












1 Answer
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1
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You are resetting the range to the complete list each time you call inplace_Quicksort in the first two lines of its code, thereby making the arguments low and high useless.



This leads to an endless recursion. No increase of maximum recursion depth will help you.



Instead give your arguments a default value. Look how it is done in this answer.






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    active

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    up vote
    1
    down vote













    You are resetting the range to the complete list each time you call inplace_Quicksort in the first two lines of its code, thereby making the arguments low and high useless.



    This leads to an endless recursion. No increase of maximum recursion depth will help you.



    Instead give your arguments a default value. Look how it is done in this answer.






    share|improve this answer

























      up vote
      1
      down vote













      You are resetting the range to the complete list each time you call inplace_Quicksort in the first two lines of its code, thereby making the arguments low and high useless.



      This leads to an endless recursion. No increase of maximum recursion depth will help you.



      Instead give your arguments a default value. Look how it is done in this answer.






      share|improve this answer























        up vote
        1
        down vote










        up vote
        1
        down vote









        You are resetting the range to the complete list each time you call inplace_Quicksort in the first two lines of its code, thereby making the arguments low and high useless.



        This leads to an endless recursion. No increase of maximum recursion depth will help you.



        Instead give your arguments a default value. Look how it is done in this answer.






        share|improve this answer












        You are resetting the range to the complete list each time you call inplace_Quicksort in the first two lines of its code, thereby making the arguments low and high useless.



        This leads to an endless recursion. No increase of maximum recursion depth will help you.



        Instead give your arguments a default value. Look how it is done in this answer.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered Nov 10 at 16:18









        trincot

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