Some compiler are not in capacity at linking stage to find out inlined
definition declared in xFemMatric.cc.
Please do not put declaration in header !!! It would add unwanted
dependency to xSolverBase "library" (header xBlasDef.h) to any code
including xFemMatrix.h. As xFemMatrix.h is include by xForm.h almost
every thing become dependant of xFemMatrix.h ... For examble xExport
would depend on xSolverBase if implementation apears in xFemMatrix.h

Note that it does'nt mean that compiler will not do inlining
optimization with this function axpy ...