This blog is updated daily.
A general description is here.
‘summary.default()’ no longer rounds, but its print method does resulting in less extraneous rounding, notably of numbers in the ten thousands.
The JIT (‘Just In Time’) byte code compiler is now enabled by default at level 3. This means functions will be compiled on first or second use and top-level loops will be compiled and then run. Thanks to Tomas Kalibera for extensive work to make this possible.
For now, the compiler will not compile code containing explicit calls to ‘browser()’: this is to support single stepping from the ‘browser()’ call.
JIT compilation can be disabled using ‘compiler::enableJIT(0)’ or by setting environment variable ‘R_ENABLE_JIT’ to ‘0’.
Check customization via environment variables to detect side effects of ‘.Call()’ and ‘.External()’ calls which alter their arguments is described in §8 of the ‘R Internals’ manual.
‘R CMD build’ and ‘R CMD check’ now use the _union_ of ‘R_LIBS’ and ‘.libPaths()’. They may not be equivalent, e.g., when the latter is determined by ‘R_PROFILE’.
The new option ‘R CMD check --no-stop-on-test-error’ allows running the remaining tests (under ‘tests/’) even if one gave an error.