That looks like a bug to me: we should not see that error message! Incidentally, if you insert I=QQbar(I) at the top then you should not need most of the subsequent explicit QQbar() calls:
sage: I=QQbar(I) sage: v1 = sqrt(QQbar(3)) sage: v2 = 999/1000*I sage: v3 = (1 + v1)/2 + v2*(-3 - v1)/2 sage: v4 = (3 - v1)/2 + v2*(1 - v1)/2 sage: v5 = v3*(1/2) + v4*(500/999*I) sage: v6 = v3*(1/2) + v4*(-500/999*I) sage: v7 = -(v5/v6).conjugate() - (v5.abs())/v5/v6.conjugate()*I sage: v8 = -(v5/v6).conjugate() + (v5.abs())/v5/v6.conjugate()*I sage: v9 = v8.abs() sage: v10 = v7.abs() sage: v11 = (v7 - v8 + (v9*v9)*v7 - (v10*v10)*v8)/ (v8.conjugate()*v7 - v7.conjugate()*v8) sage: v12 = (v11*I - (-I)*v11.conjugate())/2/I sage: v13 = v12.abs() sage: v14 = (1 - (1 - 1/(v13*v13)).sqrt())*v12 sage: time v14.real() CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s Wall time: 0.00 s -0.5773508481209188? This also caused the error message to go away. Note that in your code I was a symbolic object, so you were mixing symbolic and algebraic objects in an unnecessary (and probably inefficient) way. John 2010/1/5 Håkan Granath <[email protected]>: > Hi, > > It seems computations in QQbar is sometimes much slower in Sage > 4.3 than in the previous version. Here is an example (I am sorry > if it is too convoluted): > > v1 = sqrt(QQbar(3)) > v2 = QQbar(999/1000*I) > v3 = (1 + v1)/2 + v2*(-3 - v1)/2 > v4 = (3 - v1)/2 + v2*(1 - v1)/2 > v5 = v3*(1/2) + v4*QQbar(500/999*I) > v6 = v3*(1/2) + v4*QQbar(-500/999*I) > v7 = -(v5/v6).conjugate() - QQbar(abs(v5))/v5/v6.conjugate()*QQbar(I) > v8 = -(v5/v6).conjugate() + QQbar(abs(v5))/v5/v6.conjugate()*QQbar(I) > v9 = abs(v8) > v10 = abs(v7) > v11 = (v7 - v8 + QQbar(v9*v9)*v7 - QQbar(v10*v10)*v8)/\ > (v8.conjugate()*v7 - v7.conjugate()*v8) > v12 = (v11*QQbar(I) - QQbar(-I)*v11.conjugate())/2/QQbar(I) > v13 = abs(v12) > v14 = QQbar(1 - sqrt(1 - 1/(v13*v13)))*v12 > time real(v14) > > In Sage 4.3 I get the output: > > Exception TypeError: TypeError('Unable to convert number to real > interval.',) in 'sage.symbolic.pynac.py_is_real' ignored > CPU times: user 67.94 s, sys: 0.30 s, total: 68.23 s > Wall time: 68.68 s > -0.5773508481209188? > > In Sage 4.2.1 on the same computer I get the output: > > CPU times: user 0.00 s, sys: 0.00 s, total: 0.00 s > Wall time: 0.00 s > -0.5773508481209188? > > Should this be considered a bug? > > /Håkan > > -- > To post to this group, send an email to [email protected] > To unsubscribe from this group, send an email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
