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From: SourceForge.net <noreply@so...>  20090117 22:46:24

Bugs item #626760, was opened at 20021022 10:19 Message generated for change (Comment added) made by crategus You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=626760&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core Group: None >Status: Pending >Resolution: Wont Fix Priority: 5 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: zeroequiv extremely slow (minor) Initial Comment: expr: LOG(x^2+SQRT(2)*x+1) LOG(x^2SQRT(2)*x+1) +2*ATAN((2*x+SQRT(2))/SQRT(2)) +2*ATAN((2*xSQRT(2))/SQRT(2)) +SQRT(2)*LOG(x+1) SQRT(2)*LOG(x1) 2*SQRT(2)*ATAN(1/x)$ zeroequiv(expr,x) takes over a minute, though it is not at all subtle how nonzero it is: rectform(expr),numer, ..., x=0.1 => 3.314.44i ..., x=0.9 => 6.394.44i ..., x=1.1 => 7.38 ..., x=1.5 => 6.38 ..., x=20 => 6.28 Zeroequiv is really supposed to be quick and dirty....  >Comment By: Dieter Kaiser (crategus) Date: 20090117 22:35 Message: This bug report is related to SF[593530] "Zeroequiv issues". zeroequiv is not used for in core functions. Problems are known and documented. This is the result for the example: (%i9) expr:LOG(x^2+SQRT(2)*x+1)LOG(x^2SQRT(2)*x+1)+2*ATAN((2*x+SQRT(2))/SQRT(2)) +2*ATAN((2*xSQRT(2))/SQRT(2))+SQRT(2)*LOG(x+1) SQRT(2)*LOG(x1)2*SQRT(2)*ATAN(1/x) (%i10) zeroequiv(expr,x); (%o10) dontknow On a Windows system with GCL 2.6.8 and a CPU with 1.8 GHZ we get (%i11) for i:1 thru 100000 do zeroequiv(expr,x); Evaluation took 15.8900 seconds (15.8900 elapsed) (%o11) done One call to zeroequiv needs about 16/100,000 seconds. Setting resolution to "wont fix" and status to pending. Dieter Kaiser  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=626760&group_id=4933 
From: SourceForge.net <noreply@so...>  20090117 22:46:50

Bugs item #626760, was opened at 20021022 04:19 Message generated for change (Comment added) made by macrakis You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=626760&group_id=4933 Please note that this message will contain a full copy of the comment thread, including the initial issue submission, for this request, not just the latest update. Category: Lisp Core Group: None >Status: Closed >Resolution: Fixed Priority: 5 Private: No Submitted By: Stavros Macrakis (macrakis) Assigned to: Nobody/Anonymous (nobody) Summary: zeroequiv extremely slow (minor) Initial Comment: expr: LOG(x^2+SQRT(2)*x+1) LOG(x^2SQRT(2)*x+1) +2*ATAN((2*x+SQRT(2))/SQRT(2)) +2*ATAN((2*xSQRT(2))/SQRT(2)) +SQRT(2)*LOG(x+1) SQRT(2)*LOG(x1) 2*SQRT(2)*ATAN(1/x)$ zeroequiv(expr,x) takes over a minute, though it is not at all subtle how nonzero it is: rectform(expr),numer, ..., x=0.1 => 3.314.44i ..., x=0.9 => 6.394.44i ..., x=1.1 => 7.38 ..., x=1.5 => 6.38 ..., x=20 => 6.28 Zeroequiv is really supposed to be quick and dirty....  >Comment By: Stavros Macrakis (macrakis) Date: 20090117 16:49 Message: In Maxima 5.15, the original expression (but in lower case) takes 0.02 sec and correctly gives false. zeroequiv(LOG(1),x) correctly gives dontknow and returns instantaneously since Maxima function names are now lowercase (unlike in 2002 when the bug report was submitted). Closing as fixed.  Comment By: Dieter Kaiser (crategus) Date: 20090117 16:35 Message: This bug report is related to SF[593530] "Zeroequiv issues". zeroequiv is not used for in core functions. Problems are known and documented. This is the result for the example: (%i9) expr:LOG(x^2+SQRT(2)*x+1)LOG(x^2SQRT(2)*x+1)+2*ATAN((2*x+SQRT(2))/SQRT(2)) +2*ATAN((2*xSQRT(2))/SQRT(2))+SQRT(2)*LOG(x+1) SQRT(2)*LOG(x1)2*SQRT(2)*ATAN(1/x) (%i10) zeroequiv(expr,x); (%o10) dontknow On a Windows system with GCL 2.6.8 and a CPU with 1.8 GHZ we get (%i11) for i:1 thru 100000 do zeroequiv(expr,x); Evaluation took 15.8900 seconds (15.8900 elapsed) (%o11) done One call to zeroequiv needs about 16/100,000 seconds. Setting resolution to "wont fix" and status to pending. Dieter Kaiser  You can respond by visiting: https://sourceforge.net/tracker/?func=detail&atid=104933&aid=626760&group_id=4933 