scipy.special.exprel#
- scipy.special.exprel(x, out=None) = <ufunc 'exprel'>#
- Relative error exponential, - (exp(x) - 1)/x.- When x is near zero, - exp(x)is near 1, so the numerical calculation of- exp(x) - 1can suffer from catastrophic loss of precision.- exprel(x)is implemented to avoid the loss of precision that occurs when x is near zero.- Parameters:
- xndarray
- Input array. x must contain real numbers. 
- outndarray, optional
- Optional output array for the function values 
 
- Returns:
- scalar or ndarray
- (exp(x) - 1)/x, computed element-wise.
 
 - See also - Notes - Added in version 0.17.0. - Examples - >>> import numpy as np >>> from scipy.special import exprel - >>> exprel(0.01) 1.0050167084168056 >>> exprel([-0.25, -0.1, 0, 0.1, 0.25]) array([ 0.88479687, 0.95162582, 1. , 1.05170918, 1.13610167]) - Compare - exprel(5e-9)to the naive calculation. The exact value is- 1.00000000250000000416....- >>> exprel(5e-9) 1.0000000025 - >>> (np.exp(5e-9) - 1)/5e-9 0.99999999392252903