Predefined Constants

There exists some pre-defined constants in the fixed_num class, and the names of these functions are listed below.

• epsilon: the epsilon of current fixed number.

• e: natural constant.

• pi: π.

• pi_2: π/2.

Numbers Header File

The header file eirin/numbers.hpp contains the constants which same as the standard library <numbers> header file.

• They are defined in the numbers namespace.

• To be noticed that, the accuracy of these constants are based on 64-bit fixed point numbers.

• And if you want more accuracy for your custom fixed number like fixed128, you can check and use the auxiliary functions in eirin/detail/util.hpp.

• The calculation method has been illustrated in the eirin/detail/util.hpp file.

Name	Description
e_v	The mathematical constant e.
pi_v	The mathematical constant pi.
log2e_v	The logarithm of e to the base 2.
log10e_v	The logarithm of e to the base 10.
inv_pi_v	The multiplicative inverse of pi.
inv_sqrtpi_v	The multiplicative inverse of the square root of pi.
ln2_v	The natural logarithm of 2.
ln10_v	The natural logarithm of 10.
sqrt2_v	The square root of 2.
sqrt3_v	The square root of 3.
inv_sqrt3_v	The multiplicative inverse of the square root of 3.
egamma_v	The Euler-Mascheroni constant.
phi_v	The golden ratio.