EwaldUnitTests fail on current master using -DGMX_DOUBLE=ON
As per user reports, in double precision builds some PME tests fail.
Specifically, it's 96 out of 144 force gathering tests on Ubuntu/gcc 5.4.
Typical output is like this:
... Google Test trace: /home/yupinov/gromacs/master/src/gromacs/ewald/tests/pmegathertest.cpp:404: Testing force gathering with CPU for PME grid size 13 15 11, order 5, 13 atoms, without reduction /home/yupinov/gromacs/master/src/testutils/refdata.cpp:918: Failure In item: /Forces//Z Actual: 0.081070335928461704 Reference: 0.081070341914709868 Difference: 5.98625e-09 (431354640 double-prec. ULPs, rel. 7.38e-08) Tolerance: abs. 3.33067e-15, 15 ULPs ...
Looks like the forces are always computed in single precision, but I'm not sure yet why don't all the tests fail.