Joseph, The slight numerical difference on the Athlon and P4 might be causing what you saw. Even though it is not generally the case, but your molecule might get converged with more MCSCF iterations. In fact, this kind of numerical problems might happen even on the same machine under some circumstances.
I tried your molecule with 11 iterations and it got converged to 1e-6 (see below). Jun Li ITER. MIC NCI NEG ENERGY(VAR) ENERGY(PROJ) ENERGY CHANGE GRAD(0) GRAD(ORB) GRAD(CI) STEP TIME 1 90 32 0 -547.03057272 -547.10702891 -0.07645618 0.19252296 0.00011045 0.22630187 0.12D+01 0.94 2 34 42 0 -547.10516036 -547.10722947 -0.00206911 0.05331612 0.00000060 0.00116733 0.20D+00 1.90 3 44 42 0 -547.10724012 -547.10724010 0.00000003 0.00051998 0.00000000 0.00031419 0.59D-02 2.88 4 44 42 0 -547.10724011 -547.10724051 -0.00000040 0.00000941 0.00000001 0.00144092 0.19D-02 3.85 5 51 42 0 -547.10724071 -547.10723926 0.00000146 0.00009339 0.00000000 0.00370414 0.30D-02 4.83 6 50 42 0 -547.10724022 -547.10727147 -0.00003125 0.00032489 0.00000001 0.02154316 0.15D-01 5.82 7 53 42 0 -547.10728673 -547.10727240 0.00001433 0.00098588 0.00000001 0.02303741 0.47D-02 6.78 8 49 42 0 -547.10729852 -547.10771889 -0.00042038 0.00066603 0.00000010 0.03035252 0.76D-01 7.78 9 41 42 0 -547.10782141 -547.10797400 -0.00015260 0.00669151 0.00000001 0.00296160 0.26D-01 8.71 10 37 39 0 -547.10797529 -547.10797602 -0.00000074 0.00027396 0.00000004 0.00019212 0.27D-02 9.66 11 31 21 0 -547.10797603 -547.10797603 -0.00000000 0.00000435 0.00000021 0.00002356 0.19D-03 10.35 ** WVFN **** CONVERGENCE REACHED, FINAL GRADIENT: 0.61D-06 -----Original Message----- From: Joseph Lane [mailto:[EMAIL PROTECTED] Sent: Wednesday, May 12, 2004 4:04 PM To: [EMAIL PROTECTED] Subject: [molpro-user] CASSCF Converges on Athlon, Fails on Intel P4 Good morning, I am unable to get the following input file to converge on a P4 machine, however I have no problems running it using athlon architecture. We are running 2002.6 on both machines. ***,SO2 mem, 40, M gprint,orbitals=13,civector r1=1.431 ang, theta=119.3 geometry={Z; S; O1,S,r1; O2,S,r1,O1,theta} basis=AVDZ OCC=[15,4]; CLOSED=[11,2]; hf casscf; WF, 32,1,0; State,2; WF, 32,2,2; WF, 32,2,0; State,2; The first output is for the P4 machine, the second for the athlon < 1 90 32 0 -547.03057257 -547.10726685 -0.07669429 0.19252516 0.00001838 0.19861877 0.12D+01 2.48 < 2 34 42 0 -547.10524588 -547.10723025 -0.00198437 0.05385009 0.00000024 0.00073630 0.19D+00 4.75 < 3 43 42 0 -547.10723951 -547.10725256 -0.00001305 0.00044552 0.00000004 0.01231582 0.12D-01 7.19 < 4 44 42 0 -547.10725850 -547.10723638 0.00002212 0.00038639 0.00000005 0.01342121 0.27D-01 9.66 < < *** NO CONVERGENCE *** --- > 1 100 32 0 -547.03057257 -547.10636764 -0.07579507 > 0.19252516 0.00020290 0.31723526 0.12D+01 3.20 > 2 42 42 0 -547.10493860 -547.10722842 -0.00228983 > 0.05227518 0.00000001 0.00148456 0.21D+00 5.82 > 3 43 42 0 -547.10724233 -547.10724190 0.00000044 > 0.00071918 0.00000000 0.00336102 0.94D-02 8.77 > 4 43 42 0 -547.10724284 -547.10724236 0.00000048 > 0.00009874 0.00000001 0.00447644 0.87D-02 11.57 > 5 42 42 0 -547.10724353 -547.10724009 0.00000344 > 0.00012048 0.00000000 0.00026444 0.38D-02 14.41 > 6 44 24 0 -547.10724009 -547.10724010 -0.00000001 > 0.00000605 0.00000000 0.00019460 0.21D-03 16.67 > ** WVFN **** CONVERGENCE REACHED, FINAL GRADIENT: 0.13D-04 Any suggestions would be most appreciated Regards Joseph Lane
