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NWChem Known Bugs in version 4.5

Below is a list of the known bugs in NWChem 4.5. If you believe that you have found bugs that are not listed here, please send your bug report using the correct channel listed in the Reporting Problems with NWChem page.

1. Direct MP2 optimizations
2. Quantum molecular dynamics only works for SCF and DFT
3. Problem with RHF GIAO calculations on TMS molecules using basis sets that contain d functions
4. Problem in TI/PME evaulations
5. Possible compile problems with True64 Compaq Fortran
6. Medium and large size calculation under Linux produce NaNs

Direct MP2 optimizations:

MP2 optimizations that are performed with the direct option can have problems with CPHF convergence. In this case, the user is advised to use the default options which is a semi-direct calculation.

Quantum molecular dynamics only works for SCF and DFT

A fix is now available upon request from nwchem-support@emsl.pnl.gov.

Problem with RHF GIAO calculations on TMS molecules using basis sets that contain d functions

A fix will be available in the next release.

Problem in TI/PME evaulations

A fix will be available in the next release.

Possible compile problems with True64 Compaq Fortran

Some versions of True64 Compaq Fortran default f77 to point to f90 and the compile will break because of problems with cpp and f90. This has been reported for V5.3-915. There are three known solutions:

1. Change the f77 link to point to f77 instead of f90,
2. Add the flag -old_f77 as the first flag in the FC definition of the DECOSF section of the $NWCHEM_TOP/src/config/makefile.h file, or
3. Upgrade to version X5.3-1155 plus the patches at http://www6.compaq.com/fortran/dfau.html#updates.

Medium and large size calculation under Linux produce NaNs

2.2 Linux kernels are known to produce random wrong floating point arithmetic (eventually causing NaNs), see for example:

http://www.ccl.net/cgi-bin/ccl/message.cgi?2000+06+06+002
http://www.ccl.net/cgi-bin/ccl/message.cgi?2001+02+23+012
BUG: Global FPU corruption in 2.2
Re: BUG: Global FPU corruption in 2.2

We have experienced the same problems running NWChem with a 2.2.x kernel. This is likely due to FPU problems that has been fixed in kernel 2.2.20 and in the 2.4 series.

http://www.kernel.org/pub/linux/kernel/v2.4/

or to upgrade your 2.2 kernel to version 2.2.20, whose source is available at

http://www.kernel.org/pub/linux/kernel/v2.2/linux-2.2.20.tar.gz