Re: [Tutor] what is 'doubleword alignment'?
On Sun, Jul 17, 2011 at 9:15 PM, Walter Prins wpr...@gmail.com wrote: On 17 July 2011 15:26, Lisi lisi.re...@gmail.com wrote: Sorry to be slow. Blame virtually no sleep last night ;-( But even were the power of two bit correct (and I see subsequently that it is not), how is 18 a power of two? The 18 bytes is a bit of an irrelevance. The point is that if the start of the buffer falls on a dword (double word) alligned memory location then in theory the access should be faster. The term is a little bit ambiguous because strictly speaking different processors have different word sizes. Even so, usually when people speak of double-word alignment, it's often the case that the term word in such a context has its original meaning, e.g. 16 bits. A dword is then 32bits or 4 bytes. A doubleword aligned memory address is, using these assumptions, therefore an address that is divisible by 4. Obviously if the word size is 32bits, then a double word would be 64bits and a doubleword aligned address would need to be divisible by 8. As an aside, this type of optimization is often taken care of by compilers under the hood, and in any case it's generally not something that you'll really be considering as a Python programmer. (If however you were working on one of the Python runtimes or implementations, then you might well be sometimes considering this type of thing, depending on exactly how performance critical what you are working might be and what the runtime was being implemented in.) It's not just about performance. Some hardware simply cannot access data that is not correctly aligned. C programs that indiscriminately cast among pointers to types of different sizes are a pain to port off lenient architectures like x86. If you're writing C code that deals with pointers, you *always* need to keep alignment in mind. -- regards, kushal ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] Good Book
Dear All Pythonist, I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. I need your recommendation, thanks before . . . -- It is no more than the conspiracy of 0 and 1 [decrypthor] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Book
There's a free ebook aimed at beginners here:http://inventwithpython.com/ Regards Peter Lavelle On 18/07/11 09:26, Ryan wrote: Dear All Pythonist, I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. I need your recommendation, thanks before . . . -- It is no more than the conspiracy of 0 and 1 [decrypthor] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor -- LinkedIn Profile: http://linkedin.com/in/pmjlavelle Twitter: http://twitter.com/pmjlavelle ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Book
Ok, thank you All . . . On Mon, Jul 18, 2011 at 3:36 PM, Peter Lavelle li...@solderintheveins.co.uk wrote: ** There's a free ebook aimed at beginners here:http://inventwithpython.com/ Regards Peter Lavelle On 18/07/11 09:26, Ryan wrote: Dear All Pythonist, I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. I need your recommendation, thanks before . . . -- It is no more than the conspiracy of 0 and 1 [decrypthor] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options:http://mail.python.org/mailman/listinfo/tutor -- LinkedIn Profile: http://linkedin.com/in/pmjlavelle Twitter: http://twitter.com/pmjlavelle -- It is no more than the conspiracy of 0 and 1 [decrypthor] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Book
Ryan wrote: I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. There are lots of books, both paper and electronic. It depends on eactly what yopu want. Can you already program in another language? If so, the standard Python tutorial may be sufficient? If not, one of the non-programmers tutorials (like mine :-) will be better. Personally I wouldn't recommed buyoing a paper book until after you have learned the basics. Then you can decide if you want a general reference (Python in a Nutshell for example) or a specialist text like Python Network Programming, say. The Python.org site has many tutorials, in all manner of styles, it just depends what kind of tutorial you like. Ａｌａｎ Ｇ ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Book
i think, this http://openbookproject.net/thinkCSpy/index.html# is good book for you. (this http://greenteapress.com/thinkpython/thinkCSpy.pdf is pdf version ) and also a few sources: http://www.freenetpages.co.uk/hp/alan.gauld/ http://diveintopython.org/toc/index.html http://www.mindview.net/Books/TIPyhttp://www.mindview.net/Books/TIPythonthonhttp://www.mindview.net/Books/TIPython http://directory.google.com/Top/Computers/Programming/Languages/Python/FAQs,_Help,_and_Tutorials/ 2011/7/18 Ryan decrypt...@gmail.com Dear All Pythonist, I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. I need your recommendation, thanks before . . . -- It is no more than the conspiracy of 0 and 1 [decrypthor] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Book
On Monday 18 July 2011 09:26:51 Ryan wrote: Dear All Pythonist, I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. I need your recommendation, thanks before . . . I am using Learn Python The Hard Way by Zed A Shaw; http://learnpythonthehardway.org/ It is basic - assumes no knowledge of programming at all and is easy to follow. But as a beginning beginner myself, I find that I do most of my actual learning from the marvellous people on this list, with help also from my local Linux User Group. The book provides the exercises and structure. But, as has been said, your choice will depend on your own style. Lisi ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] Good Book
Actually you have a lot of books that have been quoted in www.python.org. One of them is ThinkPython book at www.thinkpython.org. Its really good. You'll also find exercises at the end of units. On Mon, Jul 18, 2011 at 1:56 PM, Ryan decrypt...@gmail.com wrote: Dear All Pythonist, I'm strarting learn python programming and I have been found many resources on it but I have a problem. I don't know, what is the best complete book for new learner like me. I need your recommendation, thanks before . . . -- It is no more than the conspiracy of 0 and 1 [decrypthor] ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
[Tutor] getting error while solving a series that estimates the value of pi
Hi, The problem is to estimate the value of pi using the following series. *1 / pi = (( 2 * sqrt(2) )/ 9801 ) * SIGMA of k[ (4k)! (1103 + 26390*k) / (k!^ 4 ) * 396^(4k) ]* *where k is [0, infinity)* * Problem is located at : ThinkPython Book, www.thinkpython.org *Pg 89, Exercise 7.5, Think Python Book. * * * the series should be considered till the last term of the sigma must be 1e-15 I have written the below code : *# program estimates the value of pi* *# Ramanujan's series... * *import math* * * *def fact(n) : # def of factorial function.* *if n 0 :* * return n * fact(n-1)* *if n == 0 :* * return 1* * * *k = 0* *tot = 0* *temp1 = 0* *while k = 0 and temp1 == 0 :* * * * a = ( 2 * math.sqrt(2) ) / 9801 # first term before sigma * * nu = fact (4*k) * (1103 + (26390*k) ) # numerator of series* * de = pow( fact(k), 4 ) * pow ( 396, 4*k ) # denominator of series* * * * if de / nu 1e-15 : * *temp = nu / de* *tot = tot + temp* *temp1 = 0 * *k = k + 1 * * elif de / nu == 1e-15 :* * series = a * tot * * k = k + 1* * temp1 = 0* * elif de / nu 1e-15 :* * print series* * temp1 = 1* I am getting the following error : which is completely surprising! *Traceback (most recent call last):* * File pi.py, line 30, in module* *print series* *NameError: name 'series' is not defined* * * Thus I have removed name 'series' and replaced with *a*tot, * now I am getting this error *Traceback (most recent call last):* * File pi.py, line 30, in module* *print 1 / (a * tot)* *ZeroDivisionError: float divisio*n Thus I changed the first highlighted lines to *nu = float (fact (4*k) * (1103 + (26390*k) ) )* * de = float (pow( fact(k), 4 ) * pow ( 396, 4*k )) * now I am getting * Traceback (most recent call last):* * File pi.py, line 18, in module* *de = float (pow( fact(k), 4 ) * pow ( 396, 4*k ) )* *OverflowError: long int too large to convert to float* *help me out of this problem, how could I fix this* ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] getting error while solving a series that estimates the value of pi
On Mon, Jul 18, 2011 at 6:10 PM, surya k sur...@live.com wrote: Hi, The problem is to estimate the value of pi using the following series. *1 / pi = (( 2 * sqrt(2) )/ 9801 ) * SIGMA of k[ (4k)! (1103 + 26390*k) / (k!^ 4 ) * 396^(4k) ]* *where k is [0, infinity)* * Problem is located at : ThinkPython Book, www.thinkpython.org *Pg 89, Exercise 7.5, Think Python Book. * * * the series should be considered till the last term of the sigma must be 1e-15 I have written the below code : *# program estimates the value of pi* *# Ramanujan's series... * *import math* * * *def fact(n) : # def of factorial function.* *if n 0 :* * return n * fact(n-1)* *if n == 0 :* * return 1* * * *k = 0* *tot = 0* *temp1 = 0* *while k = 0 and temp1 == 0 :* * * * a = ( 2 * math.sqrt(2) ) / 9801 # first term before sigma * * nu = fact (4*k) * (1103 + (26390*k) ) # numerator of series* * de = pow( fact(k), 4 ) * pow ( 396, 4*k ) # denominator of series* * * * if de / nu 1e-15 : * *temp = nu / de* *tot = tot + temp* *temp1 = 0 * *k = k + 1 * * elif de / nu == 1e-15 :* * series = a * tot * * k = k + 1* * temp1 = 0* * elif de / nu 1e-15 :* * print series* * temp1 = 1* I am getting the following error : which is completely surprising! *Traceback (most recent call last):* * File pi.py, line 30, in module* *print series* *NameError: name 'series' is not defined* * * Thus I have removed name 'series' and replaced with *a*tot, * now I am getting this error *Traceback (most recent call last):* * File pi.py, line 30, in module* *print 1 / (a * tot)* *ZeroDivisionError: float divisio*n Thus I changed the first highlighted lines to *nu = float (fact (4*k) * (1103 + (26390*k) ) )* * de = float (pow( fact(k), 4 ) * pow ( 396, 4*k )) * now I am getting * Traceback (most recent call last):* * File pi.py, line 18, in module* *de = float (pow( fact(k), 4 ) * pow ( 396, 4*k ) )* *OverflowError: long int too large to convert to float* *help me out of this problem, how could I fix this* You have the definitions of numerator and denominator switched. -- André Engels, andreeng...@gmail.com ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] getting error while solving a series that estimates the value of pi
surya k wrote: *k = 0* *tot = 0* *temp1 = 0* *while k = 0 and temp1 == 0 :* * a = ( 2 * math.sqrt(2) ) / 9801 # first term before sigma * * nu = fact (4*k) * (1103 + (26390*k) ) # numerator of series* * de = pow( fact(k), 4 ) * pow ( 396, 4*k ) # denominator of series* * * * if de / nu 1e-15 : * *temp = nu / de* *tot = tot + temp* *temp1 = 0 * *k = k + 1 * * elif de / nu == 1e-15 :* * series = a * tot * Note that this is the only place you ever define series * k = k + 1* * temp1 = 0* * elif de / nu 1e-15 :* * print series* So if you ever get here without de/nu having previously been *exactly* 1e-15 (which is pretty likely IMHO) you will get a name error. * temp1 = 1* I am getting the following error : which is completely surprising! *Traceback (most recent call last):* * File pi.py, line 30, in module* *print series* *NameError: name 'series' is not defined* Doesn't surprise me at all... Thus I have removed name 'series' and replaced with *a*tot, * now I am getting this error This is known as poke 'n hope debugging. Better to work out why you got the previous error message and fix it there. print statements are your friend HTH, Alan G, ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] getting error while solving a series that estimates the value of pi
On Mon, Jul 18, 2011 at 12:10 PM, surya k sur...@live.com wrote: Hi, The problem is to estimate the value of pi using the following series. *1 / pi = (( 2 * sqrt(2) )/ 9801 ) * SIGMA of k[ (4k)! (1103 + 26390*k) / (k!^ 4 ) * 396^(4k) ]* *where k is [0, infinity)* * Problem is located at : ThinkPython Book, www.thinkpython.org *Pg 89, Exercise 7.5, Think Python Book. * * * the series should be considered till the last term of the sigma must be 1e-15 I have written the below code : *# program estimates the value of pi* *# Ramanujan's series... * *import math* * * *def fact(n) : # def of factorial function.* *if n 0 :* * return n * fact(n-1)* *if n == 0 :* * return 1* * * *k = 0* *tot = 0* *temp1 = 0* *while k = 0 and temp1 == 0 :* * * * a = ( 2 * math.sqrt(2) ) / 9801 # first term before sigma * * nu = fact (4*k) * (1103 + (26390*k) ) # numerator of series* * de = pow( fact(k), 4 ) * pow ( 396, 4*k ) # denominator of series* * * * if de / nu 1e-15 : * *temp = nu / de* *tot = tot + temp* *temp1 = 0 * *k = k + 1 * * elif de / nu == 1e-15 :* * series = a * tot * * k = k + 1* * temp1 = 0* * elif de / nu 1e-15 :* * print series* * temp1 = 1* I am getting the following error : which is completely surprising! *Traceback (most recent call last):* * File pi.py, line 30, in module* *print series* *NameError: name 'series' is not defined* * * Thus I have removed name 'series' and replaced with *a*tot, * now I am getting this error *Traceback (most recent call last):* * File pi.py, line 30, in module* *print 1 / (a * tot)* *ZeroDivisionError: float divisio*n Thus I changed the first highlighted lines to *nu = float (fact (4*k) * (1103 + (26390*k) ) )* * de = float (pow( fact(k), 4 ) * pow ( 396, 4*k )) * now I am getting * Traceback (most recent call last):* * File pi.py, line 18, in module* *de = float (pow( fact(k), 4 ) * pow ( 396, 4*k ) )* *OverflowError: long int too large to convert to float* *help me out of this problem, how could I fix this* ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor I am getting the following error : which is completely surprising! You only define series when nu/de == XXX. Just don't print series outside of where it is defined, or print it outside of the while loop if you can be assured it is defined when the while loop ends. Even so, you would still end up with the overflow error, because you have de / nu and I'm assuming you want nu / de. As an aside, you might want to consider creating a variable above all the if statements called nude = nu / de and replace all of the nu / de 's to nude. This way you only divide once and not (potentially) three times per loop. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
Re: [Tutor] getting error while solving a series that estimates the value of pi
Let me write the code again.. Thanks for your help. On Mon, Jul 18, 2011 at 10:38 PM, James Reynolds eire1...@gmail.com wrote: On Mon, Jul 18, 2011 at 12:10 PM, surya k sur...@live.com wrote: Hi, The problem is to estimate the value of pi using the following series. *1 / pi = (( 2 * sqrt(2) )/ 9801 ) * SIGMA of k[ (4k)! (1103 + 26390*k) / (k!^ 4 ) * 396^(4k) ]* *where k is [0, infinity)* * Problem is located at : ThinkPython Book, www.thinkpython.org *Pg 89, Exercise 7.5, Think Python Book. * * * the series should be considered till the last term of the sigma must be 1e-15 I have written the below code : *# program estimates the value of pi* *# Ramanujan's series... * *import math* * * *def fact(n) : # def of factorial function.* *if n 0 :* * return n * fact(n-1)* *if n == 0 :* * return 1* * * *k = 0* *tot = 0* *temp1 = 0* *while k = 0 and temp1 == 0 :* * * * a = ( 2 * math.sqrt(2) ) / 9801 # first term before sigma * * nu = fact (4*k) * (1103 + (26390*k) ) # numerator of series* * de = pow( fact(k), 4 ) * pow ( 396, 4*k ) # denominator of series * * * * if de / nu 1e-15 : * *temp = nu / de* *tot = tot + temp* *temp1 = 0 * *k = k + 1 * * elif de / nu == 1e-15 :* * series = a * tot * * k = k + 1* * temp1 = 0* * elif de / nu 1e-15 :* * print series* * temp1 = 1* I am getting the following error : which is completely surprising! *Traceback (most recent call last):* * File pi.py, line 30, in module* *print series* *NameError: name 'series' is not defined* * * Thus I have removed name 'series' and replaced with *a*tot, * now I am getting this error *Traceback (most recent call last):* * File pi.py, line 30, in module* *print 1 / (a * tot)* *ZeroDivisionError: float divisio*n Thus I changed the first highlighted lines to *nu = float (fact (4*k) * (1103 + (26390*k) ) )* * de = float (pow( fact(k), 4 ) * pow ( 396, 4*k )) * now I am getting * Traceback (most recent call last):* * File pi.py, line 18, in module* *de = float (pow( fact(k), 4 ) * pow ( 396, 4*k ) )* *OverflowError: long int too large to convert to float* *help me out of this problem, how could I fix this* ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor I am getting the following error : which is completely surprising! You only define series when nu/de == XXX. Just don't print series outside of where it is defined, or print it outside of the while loop if you can be assured it is defined when the while loop ends. Even so, you would still end up with the overflow error, because you have de / nu and I'm assuming you want nu / de. As an aside, you might want to consider creating a variable above all the if statements called nude = nu / de and replace all of the nu / de 's to nude. This way you only divide once and not (potentially) three times per loop. ___ Tutor maillist - Tutor@python.org To unsubscribe or change subscription options: http://mail.python.org/mailman/listinfo/tutor
