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reciprocal

Started by BloodLust666 Oct 18, 2005 at 10:29 PM 2 replies 450+ views

Original Post

Oct 18, 2005 at 10:29 PM

is there a reciprocal function for C++? yea i could just make one but if there's a standard one then i'll use it. i mainly found the problem when i tried (1/x) where x became 0 rarely, but still possible..

K_I_L_E_R

Oct 18, 2005 at 11:14 PM

create your own function that handles the "div by zero" issue.
Otherwise just do:

x = (x == 0) ? x : (1/x);

EDIT: I would just like to say that I'm implying there is no such function in the std library.

[Edited by - K_I_L_E_R on October 19, 2005 12:14:46 AM]

ury

Oct 19, 2005 at 3:02 AM

In order to avoid underflows and denormals, I'd really recommend using something like:

y = (abs(x) < EPSLILON) ? 0.0 : (1.0/x);

EPSILON depends on the floating point precission.

JohnBolton

132

JohnBolton

Oct 20, 2005 at 2:48 AM

Quote:
Original post by ury
In order to avoid underflows and denormals, I'd really recommend using something like:

y = (abs(x) < EPSLILON) ? 0.0 : (1.0/x);

EPSILON depends on the floating point precission.

fabs (or fabsf), not abs

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