Update qchem.md

docs/Documentation/Applications/qchem.md

@@ -4,61 +4,86 @@
 
 ## Running Q-Chem
 
-The `q-chem` module should be loaded to set up the necessary environment. The `module help` output can provide more detail. In particular, the modulefile does not set the needed environment variable `QCSCRATCH`, as this is likely unique for each run. `QCLOCALSCR` is set by default to `/tmp/scratch`, but one may wish to point to a more persistent location if files written to local scratch need to be accessed after the job completes. Users can easily do this in their Slurm scripts or at the command line via `export` (Bash) or `setenv` (csh). 
+The `q-chem` module should be loaded to set up the necessary environment. The `module help` output can provide more detail. In particular, the modulefile does not set the needed environment variable `QCSCRATCH`, as this is likely unique for each run. Users should do this in their Slurm scripts or at the command line via `export` (bash) or `setenv` (csh). 
 
 The simplest means of starting a Q-Chem job is via the supplied `qchem` wrapper. The general syntax is: 
 
 `qchem -slurm <-nt number_of_OpenMP_threads> <input file> <output file> <savename>`
 
-For example, to run a job with 36 threads:
+For example, to run a job with 104 threads:
 
-`qchem -slurm -nt 36 example.in`
+`qchem -slurm -nt 104 example.in`
 
 !!! tip "Note"
 	 The Q-Chem input file must be in the same directory in which you issue the qchem command. In other words, `qchem ... SOMEPATH/<input file>` won't work. 
 
-For a full list of which types of calculation are parallelized and the types of parallelism, see the [Q-Chem User's Manual](https://manual.q-chem.com/5.3/).
+For a full list of which types of calculation are parallelized and the types of parallelism, see the [Q-Chem User's Manual](https://manual.q-chem.com/6.2/).
 
 To save certain intermediate files for, *e.g.*, restart, a directory name needs to be provided. If not provided, all scratch files will be automatically deleted at job's end by default. If provided, a directory `$QCSCRATCH/savename` will be created and will hold saved files. In order to save all intermediate files, you can add the `-save` option. 
 
-A template Slurm script to run Q-Chem with 36 threads is:
+A template Slurm script to run Q-Chem with 104 threads is:
 
-??? example "Sample Submission Script"
+### Sample Submission Script for Kestrel
 
-	```bash
+```
+ 	#!/bin/bash
 	#SBATCH --job-name=my_qchem_job
 	#SBATCH --account=my_allocation_ID
-	#SBATCH --ntasks=36
-	#SBATCH --time=01:00:00
+	#SBATCH --nodes=1
+ 	#SBATCH --tasks-per-node=104
+  	#SBATCH --time=01:00:00
+   	#SBATCH --exclusive
 	#SBATCH --mail-type=BEGIN,END,FAIL
 	#SBATCH [email protected]
 	#SBATCH --output=std-%j.out
 	#SBATCH --error=std-%j.err
 
 	# Load the Q-Chem environment
-	module load q-chem
-
-	# Go to the location of job files, presumably from where this file was submitted
-	cd $SLURM_SUBMIT_DIR
-
-	# Set up scratch space
-	SCRATCHY=/scratch/$USER/${SLURM_JOB_NAME:?}
-	if [ -d $SCRATCHY ]
-	then
-	   rm -r $SCRATCHY
+	module load q-chem/6.2
+
+	if [ -e /dev/nvme0n1 ]; then
+	 SCRATCH=$TMPDIR
+	 echo "This node has a local storage and will use $SCRATCH as the scratch path"
+	else
+	 SCRATCH=/scratch/$USER/$SLURM_JOB_ID
+	 echo "This node does not have a local storage drive and will use $SCRATCH as the scratch path"
 	fi
-	mkdir -p $SCRATCHY
-	export QCSCRATCH=$SCRATCHY
-
-	# Move files over
-	cp * $SCRATCHY/.
-	cd $SCRATCHY
-
-	# Start run. Keep restart files without intermediate temp files in directory called "my_save"
-	qchem -nt 36 job.in job.out my_save
-	```
 
-To run this script on Swift, the number of threads can be changed to 64. 
+	mkdir -p $SCRATCH
+
+	export QCSCRATCH=$SCRATCH
+	export QCLOCALSCR=$SCRATCH
+
+	jobnm=qchem_test
+
+	if [ $SLURM_JOB_NUM_NODES -gt 1 ]; then
+	 QCHEMOPT="-mpi -np $SLURM_NTASKS"
+	else
+	 QCHEMOPT="-nt $SLURM_NTASKS"
+	fi
+
+	echo Running Q-Chem with this command: qchem $QCHEMOPT $jobnm.com $jobnm.out
+	qchem $QCHEMOPT $jobnm.com $jobnm.out
+
+	rm $SCRATCH/*
+	rmdir $SCRATCH
+```
+
+To run this script on HPCs other than Kestrel, the number of threads should be changed accordingly. 
 
 A large number of example Q-Chem input examples are available in `/nopt/nrel/apps/q-chem/<version>/samples`.
 
+## Running BrianQC
+BrianQC is the GPU version of Q-Chem and can perform Q-Chem calculations on GPUs, which is significantly faster for some larger ab initio jobs. BrianQC uses the same input file as Q-Chem. To run BrianQC, please make the following changes to the sample Slurm scipt above:
+1. Add this line in the header section: "#SBATCH --gres=gpu:1"
+2. Load the BrianQC module instead of Q-Chem: "module load brianqc"
+3. Add "-gpu" in $QCHEMOPT like:
+   ```
+	if [ $SLURM_JOB_NUM_NODES -gt 1 ]; then
+	 QCHEMOPT="-gpu -mpi -np $SLURM_NTASKS"
+	else
+	 QCHEMOPT="-gpu -nt $SLURM_NTASKS"
+	fi
+   ```
+4. Submit jobs through the GPU login nodes on Kestrel or add "#SBATCH -p gpu" to the header of slurm file if running on Swift.
+