On 05/29/2013 01:54 PM, steve wrote:
Just FYI, I discovered the problem. At some point my field calculation was returning nan, I didn't notice. The nan naturally propagated to the particle trajectory and wound up as an argument to the points probe.
Passing nan into the points probe as a coordinate doesn't work. ;-)
I think we should make the probe code more robust by checking the inputs :) Thanks for the debugging!
r.
thanks, -steve
On Wednesday, May 22, 2013 9:09:42 AM UTC-6, Robert Cimrman wrote:
Hi Steve,
On 05/22/2013 04:42 PM, Steve Spicklemire wrote:
I'm using sfepy to solve for the potential in what is essentially a cylindrical lens for charged particles.
I'm attempting to use a probe to evaluate the field components (-grad(u)). Here's what I'm attempting:
def GetFieldAtPoint(res, x, y, eps=0.1): """ Return the field strength at a point x,y using eps for centered difference. """ probe = PointsProbe(( (x + eps, y), (x - eps, y), (x, y + eps), (x, y - eps)), res.pb.domain.mesh)
pars, vals = probe(res.var) vals = vals.squeeze() Ex = (vals[1]-vals[0])/(2.0*eps) Ey = (vals[3]-vals[2])/(2.0*eps) return np.array([np.isnan(Ex) and 0.0 or Ex, np.isnan(Ey) and 0.0 orEy])
But I'm getting a memory exception after several evaluations. I'll try to come up with a complete example to post.. but has anyone see this kind of trouble?
thanks, -steve
Program received signal EXC_BAD_ACCESS, Could not access memory. Reason: KERN_INVALID_ADDRESS at address: 0x00000000130e16a0 0x0000000108513b1f in __pyx_f_5sfepy_3fem_7extmods_5bases_find_ref_coors (__pyx_v_ref_coors=0x10cb28b90, __pyx_v_cells=0x10cb28b40, __pyx_v_status=
, __pyx_v_coors= , __pyx_v_ics=0x108521e60, __pyx_v_offsets=0x111c0a870, __pyx_v_iconn=0x10f152450, __pyx_v_mesh_coors=0x10cb330c0, __pyx_v_conns=0x110e3ce60, __pyx_v_eref_coorss=0x10e153950, __pyx_v_nodess=0x10e144638, __pyx_v_mtx_is=0x110e3cdd0, __pyx_v_allow_extrapolation=1, __pyx_v_close_limit=0.10000000000000001, __pyx_v_qp_eps=1.0000000000000001e-15, __pyx_v_i_max=100, __pyx_v_newton_eps=1e-08, __pyx_skip_dispatch=0) at build/src.macosx-10.6-intel-2.7/sfepy/fem/extmods/bases.c:5795 5795 __pyx_v_ig = (*__Pyx_BufPtrCContig1d(__pyx_t_5sfepy_3fem_7extmods_5types_int32 *, __pyx_bstruct_iconn.buf, __pyx_t_37, __pyx_bstride_0_iconn)); (gdb) bt #0 0x0000000108513b1f in __pyx_f_5sfepy_3fem_7extmods_5bases_find_ref_coors (__pyx_v_ref_coors=0x10cb28b90, __pyx_v_cells=0x10cb28b40, __pyx_v_status= , __pyx_v_coors= , __pyx_v_ics=0x108521e60, __pyx_v_offsets=0x111c0a870, __pyx_v_iconn=0x10f152450, __pyx_v_mesh_coors=0x10cb330c0, __pyx_v_conns=0x110e3ce60, __pyx_v_eref_coorss=0x10e153950, __pyx_v_nodess=0x10e144638, __pyx_v_mtx_is=0x110e3cdd0, __pyx_v_allow_extrapolation=1, __pyx_v_close_limit=0.10000000000000001, __pyx_v_qp_eps=1.0000000000000001e-15, __pyx_v_i_max=100, __pyx_v_newton_eps=1e-08, __pyx_skip_dispatch=0) at build/src.macosx-10.6-intel-2.7/sfepy/fem/extmods/bases.c:5795 #1 0x0000000108516b89 in __pyx_pf_5sfepy_3fem_7extmods_5bases_3find_ref_coors (__pyx_self= , __pyx_args= , __pyx_kwds= ) at build/src.macosx-10.6-intel-2.7/sfepy/fem/extmods/bases.c:6310 #2 0x00000001000c1e7d in PyEval_EvalFrameEx () This is strange, I have never seen that. I might be able to tell you more after I try the complete example.
r.