diff --git a/gstlal-inspiral/bin/gstlal_inspiral_create_dt_dphi_snr_ratio_pdfs_dag b/gstlal-inspiral/bin/gstlal_inspiral_create_dt_dphi_snr_ratio_pdfs_dag
index b6114b077c98db570cbf51a0146d66b3cb4f326f..93331c21bd974e696d50af305ec9c774f84e0644 100755
--- a/gstlal-inspiral/bin/gstlal_inspiral_create_dt_dphi_snr_ratio_pdfs_dag
+++ b/gstlal-inspiral/bin/gstlal_inspiral_create_dt_dphi_snr_ratio_pdfs_dag
@@ -18,7 +18,15 @@
 
 import os
 from gstlal import dagparts
+import argparse
 
+parser = argparse.ArgumentParser(description = 'generate a dt dphi covariance matrix')
+parser.add_argument('--psd-xml', help = 'XML containing HLV psd')
+parser.add_argument('--H-snr', type = float, help = 'H characteristic SNR')
+parser.add_argument('--L-snr', type = float, help = 'L characteristic SNR')
+parser.add_argument('--V-snr', type = float, help = 'V characteristic SNR')
+parser.add_argument("--output", help = "set the output h5 file, e.g., covmat.h5")
+args = parser.parse_args()
 
 try:
 	os.mkdir("logs")
@@ -26,15 +34,18 @@ except:
 	pass
 dag = dagparts.DAG("dt_dphi")
 
-margJob = dagparts.DAGJob("gstlal_inspiral_create_dt_dphi_snr_ratio_pdfs", condor_commands = {"request_memory":"8GB", "want_graceful_removal":"True", "kill_sig":"15", "accounting_group":"ligo.prod.o2.cbc.uber.gstlaloffline"})
-addJob = dagparts.DAGJob("gstlal_inspiral_add_dt_dphi_snr_ratio_pdfs", condor_commands = {"request_memory":"4GB", "want_graceful_removal":"True", "kill_sig":"15", "accounting_group":"ligo.prod.o2.cbc.uber.gstlaloffline"})
+covJob = dagparts.DAGJob("gstlal_inspiral_compute_dtdphideff_cov_matrix", condor_commands = {"want_graceful_removal":"True", "kill_sig":"15", "accounting_group":"ligo.prod.o3.cbc.uber.gstlaloffline"})
+margJob = dagparts.DAGJob("gstlal_inspiral_create_dt_dphi_snr_ratio_pdfs", condor_commands = {"request_memory":"7GB", "want_graceful_removal":"True", "kill_sig":"15", "accounting_group":"ligo.prod.o3.cbc.uber.gstlaloffline"})
+addJob = dagparts.DAGJob("gstlal_inspiral_add_dt_dphi_snr_ratio_pdfs", condor_commands = {"request_memory":"4GB", "want_graceful_removal":"True", "kill_sig":"15", "accounting_group":"ligo.prod.o3.cbc.uber.gstlaloffline"})
+
+covnode =  dagparts.DAGNode(covJob, dag, parent_nodes = [], opts = {"H-snr": args.H_snr, "L-snr": args.L_snr, "V-snr": args.V_snr}, input_files = {"psd-xml": args.psd_xml}, output_files = {"output":"covmat.h5"})
 
 num = 1000
 margnodes = []
 # FIXME dont hardcode 3345408, it comes from number of tiles in TimePhaseSNR
 for start in range(0, 3345408, num):
 	stop = start + num
-	margnodes.append(dagparts.DAGNode(margJob, dag, parent_nodes = [], opts = {"start":str(start), "stop":str(stop)}, output_files = {"output":"%s/inspiral_dtdphi_pdf_%d_%d.h5" % (margJob.output_path, start, stop)}))
+	margnodes.append(dagparts.DAGNode(margJob, dag, parent_nodes = [covnode], opts = {"start":str(start), "stop":str(stop)}, input_files = {"cov-mat": "covmat.h5"}, output_files = {"output":"%s/inspiral_dtdphi_pdf_%d_%d.h5" % (margJob.output_path, start, stop)}))
 
 addnode = dagparts.DAGNode(addJob, dag, parent_nodes = margnodes, input_files = {"": [n.output_files["output"] for n in margnodes]})