Modified e2d output to be sqrt of 2nd invariant

src/do_leaf_measurements.f90

@@ -162,7 +162,9 @@ do i=1+iproc,nleaves,nproc
    J2d=second_invariant(exx,eyy,ezz,exy,eyz,ezx)
    J3d=third_invariant (exx,eyy,ezz,exy,eyz,ezx)
 
-   e2dtemp(i)=J2d
+   !e2dtemp(i)=J2d
+   ! Set e2d as effective stress (sqrt of 2nd invariant) - dwhipp 12/09
+   e2dtemp(i)=sqrt(J2d)
 
    if (J2d/=0.d0) lodetemp(i)=lode_angle (J2d,J3d)/pi