Hi, while working a little with sage I encountered some problems sage has concerning numerical precision at very small numbers. I hope I can make my point with a little example.
sage: a=1e-175 sage: log(a) -402.952391273958 sage: log(2-a-2) -infinity As you can see sage has no problem evaluating log(a), but if you make some computations with a, it will be disregarded. My next approach using the numerical approximation method .n() shows also some inconsequence. sage: a.n(3000) 9.9999999999999999591421057981561172760359517840594637610381681203271426218 398700962941525716354631708608402128816567281624536848836577367469795392411 220011109485295768465799357318010252751732178407974254554038401714686355665 848001217909837164713986265000964892566636634526795754478479686133945236527 071065064513189551784144051652154369610524111495583091804490661938365977391 453819697791781023172096034811422121224133013894785904085438232868909835815 4296875000000000000000000000(...)000000000000000000000000000000000000000000000e-176 sage: (2-a-2).n(3000) 0.00000000000000000000000000000000000000(...)000000000000000000000000000000000 To put it in the right context, I am working on a program, where I first compute some constants (very small ones) which will be used afterwards. Another problem is, that I get a SymbolicArithmetic type value after some computation steps, which seem to be to complicated to work along with for sage. So I have to approximate it with .n() to use it after that point. And I think it is not the best way to approximate intermediate values, isn't it? Thank you Michael --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
