On Dec 10, 12:39 pm, "ma...@mendelu.cz" <ma...@mendelu.cz> wrote: > On 10 pro, 11:02, Harald Schilly <harald.schi...@gmail.com> wrote: > > > > (%i3) ratsimp(a), algebraic=true; > > > Ok, is it wise to do this by default if called from sage? > > Not sure (could it break something in integration for example?) but > without this we have bug described > athttp://groups.google.cz/group/sage-devel/browse_thread/thread/1220492...
I don't think there is a bug there. It's just that one form is harder to compute numerically because of rounding errors. (%i2) A1:ratsimp(A), algebraic=true$ (%i3) A2:ratsimp(A)$ (%i4) float(A1); (%o4) 139.406088405362 (%i5) float(A2); (%o5) 32.0 But they are the same: (%i6) ratsimp(A1-A2); (%o6) 0 If you compute A2 in higher precision, you will get a better result: (%i7) fpprec:256; (%o7) 256 (%i8) bfloat(A2); (%o8) 1.3940608840536196048491518637[198 digits] 6294485890103091502824365657b2 Removing radicals from the denominator is not always "simplification": (%i9) 1/(2^(1/2)+2^(1/3)+2^(1/4)); (%o9) 1/(sqrt(2)+2^(1/3)+2^(1/4)) (%i10) ratsimp(%), algebraic=true; (%o10) -(11*2^(13/4)+sqrt(2)*(2^(1/3)*(37*2^(11/4)-59*2^(5/4)-19*sqrt (2)+96)+2^(2/3)*(23*2^(11/4)+89*2^(5/4)-47*sqrt(2)+27)+11*2^(11/4)-5*2^ (9/4)+115*sqrt(2)-444)+2^(1/3)*(-19*2^(9/4)-25*2^(3/4)+3*sqrt (2)+148)+57*2^(3/2)-299*2^(3/4)+2^(2/3)*(-101*2^(3/4)-159*sqrt(2)+91*2^ (1/4)-280)-142)/(2046) HTH, Andrej -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
