We conduct a direct comparison of three different representative numerical codes for constructing models of rapidly rotating neutron stars in general relativity .
Our aim is to evaluate the accuracy of the codes and to investigate how the accuracy is affected by the choice of interpolation , domain of integration and equation of state .
In all three codes , the same physical parameters , equations of state and interpolation method are used .
We construct 25 selected models for polytropic equations of state and 22 models with realistic neutron star matter equations of state .
The three codes agree well with each other ( typical agreement is better than 0.1 % to 0.01 % ) for most models , except for the extreme assumption of uniform density stars .
We conclude that the codes can be used for the construction of highly accurate initial data configurations for polytropes of index N > 0.5 ( which typically correspond to realistic neutron stars ) , when the domain of integration includes all space and for realistic equations with no phase transitions .
With the exception of the uniform density case , the obtained values of physical parameters for the models considered in this paper can be regarded as “ standard ” and we display them in detail for all models .