modified on 29 January 2016 at 12:49 ••• 72,436 views


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NWChem Frequently Asked Questions


General information about NWChem

Where is the User's Manual?

NWChem User's Manual

Where do I go for help with a Global Arrays problem?

If you have problems with compiling the tools directory, please visit the Global Arrays Google group at or visit the Global Arrays website at

Where do I go for help with NWChem problems?

Please post your NWChem issue to the NWChem Community forums at

Where do I find the instructions for installing NWChem?

For updated instructions for compiling NWChem please visit the following URL

Installation Problems

How to fix configure: error: could not compile simple C MPI program

When compiling the tools directory, you might see the compilation stopping with the message configure: error: could not compile simple C MPI program This is most likely due to incorrect settings for the MPI_LIB, MPI_INCLUDE and LIBMPI environment variables. The suggested course of action is a) to use NWChem 6.6, b) unset all of the three variables above and c) point your PATH env. variable to the location of mpif90

What's this business with ARMCI and ARMCI_NETWORK?

ARMCI is a library used by Global Arrays (both ARMCI and GA source code is located in NWChem's tools directory). More information can be found at the following URL If your installation uses a fast network and you are aiming to get optimal communication performance, you might want to assign a non-default value to ARMCI_NETWORK. The following links contained useful information about ARMCI_NETWORK: Choosing the ARMCI library and Setting up the proper environment_variables when compiling NWChem

Input Problems

I get the message: ! warning: processed input with no task. What is wrong?

Have you used emacs to create your input file? Emacs usually does not put and an end-of-line as a last character of the file, therefore the NWChem input parser ignores the last line of your input (the one containing the task directive). To fix the problem, add one more blank line after the task line and your task directive will be executed.