Molcas Forum

Kalpa

Member

Registered: 2022-04-09

Posts: 12

IEEE_UNDERFLOW_FLAG IEEE_DENORMAL

Hello openmolcas developers!

I am a beginner openmolcas user. I have compiled the openmolcas software in my system and trying to run the very first calculation of Electronic Energy at Fixed Nuclear Geometry given in the documentation. I found in SCF.energy.CH4.err
Note: The following floating-point exceptions are signalling: IEEE_INVALID_FLAG IEEE_DIVIDE_BY_ZERO IEEE_UNDERFLOW_FLAG IEEE_DENORMAL
Note: The following floating-point exceptions are signalling: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL

Is that a normal error or something serious problem is there?

The inputs I used are as follow:

SCF.energy.CH4.input
----------------------------------------------------------------------------

*SCF energy for CH4 at a fixed nuclear geometry.
*File: SCF.energy.CH4
*
&GATEWAY
 Title = CH4 molecule
 coord = CH4.xyz
 basis = STO-3G
 group = C1

&SEWARD
&SCF

-----------------------------------------------------------------------------
CH4.xyz
-----------------------------------------------------------------------------

5
distorted CH4 coordinates in Angstroms
C    0.000000     0.000000     0.000000
H    0.000000     0.000000     1.050000
H    1.037090     0.000000    -0.366667
H   -0.542115    -0.938971    -0.383333
H   -0.565685     0.979796    -0.400000

----------------------------------------------------------------------------
in the SCF.energy.CH4.log file I found:

.
.
 ###############################################################################
 ###############################################################################
 ###                                                                         ###
 ###                                                                         ###
 ###    WARNING: RunFile label nBas                                          ###
 ###    was used       72 times                                              ###
 ###                                                                         ###
 ###                                                                         ###
 ###############################################################################
 ###############################################################################
--- Stop Module: scf at Mon Feb  6 12:51:13 2023 /rc=_RC_ALL_IS_WELL_ ---
*** files: SCF.energy.CH4.scf.molden SCF.energy.CH4.ScfOrb SCF.energy.CH4.scf.h5 xmldump
    saved to directory /home/kalpa.bhu/CALC/openmolcas/scf
--- Module scf spent 3 seconds ---

.##################.
.# Happy landing! #.
.##################.

    Timing: Wall=9.17 User=3.20 System=2.38

-------------------------------------------------------------------------------------------------------------------------------------------------
Can someone tell me what could be the problem in my problem?

Ignacio

Administrator

From: Uppsala

Registered: 2015-11-03

Posts: 1,085

Re: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL

Those are typically normal exceptions triggered inside the LAPACK library, nothing to worry about if your calculation ended correctly (as it did).

Kalpa

Member

Registered: 2022-04-09

Posts: 12

Re: IEEE_UNDERFLOW_FLAG IEEE_DENORMAL

Thank you very much for your kind response.