<div> <span id="obmessage">Jason,<br><br>Have you tried running the program with output NOT to stdout, but to file?<br>I don't think the "conversion" from GMP-internal format to decimal takes *that* much time, but the actual formatted output on-screen (think "printf") might slow things down (especially for the number of characters you're outputting)...<br><br>CU, JDO<br></span> <blockquote style="border-left: 2px solid rgb(16, 16, 255); margin-left: 5px; padding-left: 5px;">From: "賴秀琴" <chyn0610@yahoo.com.tw><br> To: gmp-discuss@swox.com<br> Subject: Low efficiency of the mpf_out_str function !<br> Date: Wed, 7 Nov 2007 21:39:13 +0800 (CST)<br> <br> </chyn0610@yahoo.com.tw><div>I am a newbie to the GMP</div> <div>and trying to run some example codes !</div> <div> </div> <div>I find the result of gmp-chudnovsky.c running strange on my computer. It shows the efficiency of the mpf_out_str function seems to be very low. When I try to calculate 800000 digits of pi , the core calculation take 13.6 sec , but the digits print-out task take more than 56 sec ( use a stop watch)</div> <div> </div> <div>why ??</div> <div> </div> <div>Jason Lin</div> <div> </div> <div>the following are the details</div> <div>-------------------</div> <div> </div> <div>djgpp 2.03<br>with gmp 4.1.2 (precompiled package)<br>on a Windows XP command console running with Pentium-4 1.6 GHz / 1G RAM</div> <div> </div> <div>d:\dp>gcc -Wall -O2 -s -o chud.exe gmp-chudnovsky.c -lm -lgmp</div> <div> </div> <div>case1:</div> <div>d:\dp>chud 500000 1           <-  to get 500000 digits</div> <div>#terms=35256, depth=17<br>sieve   time =  0.000<br>...................................................<br>bs      time =  5.110<br>   gcd  time =  0.330<br>div     time =  1.099<br>sqrt    time =  0.604<br>mul     time =  0.385<br>total   time =  7.198<br>   P size=727581 digits (1.455162)<br>   Q size=727575 digits (1.455150)<br>pi(0,35256)=</div> <div>Totally 29 sec to get the final result<br>(22 sec for the mpf_out_str function )</div> <div> </div> <div> </div> <div>case2:<br>d:\dp>chud 800000 1    <- to get 800000 digits<br>#terms=56410, depth=17<br>sieve   time =  0.000<br>...................................................<br>bs      time = 10.000<br>   gcd  time =  0.495<br>div     time =  1.923<br>sqrt    time =  0.989<br>mul     time =  0.714<br>total   time = 13.626<br>   P size=1164133 digits (1.455166)<br>   Q size=1164127 digits (1.455159)<br>pi(0,56410)=</div> <div>Totally 69 sec to get the final result<br>(56 sec for the mpf_out_str function )</div> <div> </div> <div>---------------------------------------------</div> <div>print out code in gmp-chudnovsky.c</div> <div> </div> <div>if (out&1)  {<br>    printf("pi(0,%ld)=\n", terms);<br>    mpf_out_str(stdout, 10, d+2, qi);      <---- it is the hot spot<br>    printf("\n");</div><p> ___________________________________________________________________<br> 體驗全新Yahoo!奇摩電子信箱2.0 - <a href="http://tw.rd.yahoo.com/referurl/mail/mail20/tag_1022/*http://tw.mg0.mail.yahoo.com/dc/landing"><strong>馬上體驗</strong></a>！ <br> _______________________________________________<br> gmp-discuss mailing list<br> gmp-discuss@swox.com<br> https://gmplib.org/mailman/listinfo/gmp-discuss<br> </p></blockquote> </div> <BR> -- <div> Want an e-mail address like mine? </b><br> Get a <b>free e-mail </b>account today at <a href="http://www.mail.com/Product.aspx" target="_blank">www.mail.com</a>!</div>