diff --git a/lib/pace/Install.py b/lib/pace/Install.py
index 790acd4cf4..bf4723a090 100644
--- a/lib/pace/Install.py
+++ b/lib/pace/Install.py
@@ -1,4 +1,4 @@
-# TODO#!/usr/bin/env python
+#!/usr/bin/env python
 
 """
 Install.py tool to download, compile, and setup the pace library
@@ -6,7 +6,10 @@ used to automate the steps described in the README file in this dir
 """
 
 from __future__ import print_function
-import sys, subprocess
+
+import shutil
+import subprocess
+import sys
 from argparse import ArgumentParser
 
 sys.path.append('..')
@@ -19,19 +22,17 @@ version = 'v.2021.10.25.fix2'
 
 # known checksums for different PACE versions. used to validate the download.
 checksums = { \
-        'v.2021.2.3.upd2' : '8fd1162724d349b930e474927197f20d',
-        'v.2021.4.9'      : '4db54962fbd6adcf8c18d46e1798ceb5',
-        'v.2021.9.28'     : 'f98363bb98adc7295ea63974738c2a1b',
-        'v.2021.10.25'    : 'a2ac3315c41a1a4a5c912bcb1bc9c5cc',
-        'v.2021.10.25.fix': 'e0572de57039d4afedefb25707b6ceae',
-        'v.2021.10.25.fix2': '32394d799bc282bb57696c78c456e64f'
-        }
-
+    'v.2021.2.3.upd2': '8fd1162724d349b930e474927197f20d',
+    'v.2021.4.9': '4db54962fbd6adcf8c18d46e1798ceb5',
+    'v.2021.9.28': 'f98363bb98adc7295ea63974738c2a1b',
+    'v.2021.10.25': 'a2ac3315c41a1a4a5c912bcb1bc9c5cc',
+    'v.2021.10.25.fix': 'e0572de57039d4afedefb25707b6ceae',
+    'v.2021.10.25.fix2': '32394d799bc282bb57696c78c456e64f'
+}
 
 parser = ArgumentParser(prog='Install.py',
                         description="LAMMPS library build wrapper script")
 
-
 # help message
 
 HELP = """
@@ -55,55 +56,68 @@ parser.add_argument("-v", "--version", default=version, choices=checksums.keys()
                     help="set version of PACE library to download and build (default: %s)" % version)
 parser.add_argument("-vv", "--verbose", action="store_true",
                     help="be more verbose about is happening while this script runs")
+parser.add_argument("-l", "--local", default=None,
+                    help="use local version of PACE library build")
 
 args = parser.parse_args()
 
 # print help message and exit, if neither build nor path options are given
 if not args.build:
-  parser.print_help()
-  sys.exit(HELP)
+    parser.print_help()
+    sys.exit(HELP)
 
 buildflag = args.build
 
 verboseflag = args.verbose
 version = args.version
-
+local = args.local
 
 archive_extension = "tar.gz"
 url = "https://github.com/ICAMS/lammps-user-pace/archive/refs/tags/%s.%s" % (version, archive_extension)
-unarchived_folder_name = "lammps-user-pace-%s"%(version)
+unarchived_folder_name = "lammps-user-pace-%s" % (version)
 
 # download PACE tarball, unpack, build PACE
 if buildflag:
+    if not local:
+        # download entire tarball
+        print("Downloading pace tarball ...")
+        archive_filename = "%s.%s" % (version, archive_extension)
+        download_filename = "%s/%s" % (thisdir, archive_filename)
+        print("Downloading from ", url, " to ", download_filename, end=" ")
+        geturl(url, download_filename)
+        print(" done")
 
-  # download entire tarball
+        # verify downloaded archive integrity via md5 checksum, if known.
+        if version in checksums:
+            if not checkmd5sum(checksums[version], archive_filename):
+                sys.exit("Checksum for pace library does not match")
 
-  print("Downloading pace tarball ...")
-  archive_filename = "%s.%s" % (version, archive_extension)
-  download_filename = "%s/%s" % (thisdir, archive_filename)
-  print("Downloading from ",url," to ",download_filename, end=" ")
-  geturl(url, download_filename)
-  print(" done")
+        print("Unpacking pace tarball ...")
+        src_folder = thisdir + "/src"
+        cmd = 'cd "%s"; rm -rf "%s"; tar -xvf %s; mv %s %s' % (
+            thisdir, src_folder, archive_filename, unarchived_folder_name, src_folder)
+        subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
+    else:
+        # copy from local version of library PACE
+        print("Copy pace from ", local)
+        src_folder = thisdir + "/src"
+        shutil.copytree(local, src_folder,
+                        # ignore=lambda (s1,s2): ('.git' in s1 or '.git' in s2),
+                        dirs_exist_ok=True)
 
-  # verify downloaded archive integrity via md5 checksum, if known.
-  if version in checksums:
-    if not checkmd5sum(checksums[version], archive_filename):
-      sys.exit("Checksum for pace library does not match")
 
-  print("Unpacking pace tarball ...")
-  src_folder = thisdir+"/src"
-  cmd = 'cd "%s"; rm -rf "%s"; tar -xvf %s; mv %s %s' % (thisdir, src_folder, archive_filename, unarchived_folder_name, src_folder)
-  subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
+    # build
+    print("Building libpace ...")
+    cmd = 'make lib -j2'
+    txt = subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
+    if verboseflag:
+        print(txt.decode("UTF-8"))
 
-  # build
-  print("Building libpace ...")
-  cmd = 'make lib -j2'
-  txt = subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
-  if verboseflag:
-    print(txt.decode("UTF-8"))
+    #   remove source files
 
-#   remove source files
+    print("Removing pace build files and archive ...")
+    cmd = 'make clean-build'
+    if not local:
+        cmd = ('rm %s;' % (download_filename))+cmd
+    subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
 
-  print("Removing pace build files and archive ...")
-  cmd = 'rm %s; make clean-build' % (download_filename)
-  subprocess.check_output(cmd, stderr=subprocess.STDOUT, shell=True)
diff --git a/lib/pace/Makefile b/lib/pace/Makefile
index 81f7c9db95..e6d7bff2b9 100644
--- a/lib/pace/Makefile
+++ b/lib/pace/Makefile
@@ -5,8 +5,14 @@ SHELL = /bin/sh
 YAML_CPP_PATH = src/yaml-cpp
 YAML_CPP_INC = $(YAML_CPP_PATH)/include
 
+WIGNER_CPP_INC = src/wigner-cpp/include/wigner
+
+CNPY_CPP_PATH = src/cnpy
+CNPY_CPP_INC = $(CNPY_CPP_PATH)
+CNPY_SRC_FILES =  $(CNPY_CPP_PATH)/cnpy.cpp
+
 SRC_FILES = $(wildcard src/ML-PACE/*.cpp)
-SRC = $(filter-out src/ML-PACE/pair_pace.cpp, $(SRC_FILES))
+SRC = $(filter-out src/ML-PACE/pair_pace.cpp, $(SRC_FILES)) $(CNPY_SRC_FILES)
 
 # ------ DEFINITIONS ------
 
@@ -15,7 +21,7 @@ OBJ =   $(SRC:.cpp=.o)
 
 
 # ------ SETTINGS ------
-CXXFLAGS = -O3 -fPIC -Isrc/ML-PACE -I$(YAML_CPP_INC)
+CXXFLAGS = -O3 -fPIC -Isrc/ML-PACE -I$(YAML_CPP_INC) -I$(WIGNER_CPP_INC) -I$(CNPY_CPP_INC) -DEXTRA_C_PROJECTIONS
 
 ARCHIVE =	ar
 ARCHFLAG =	-rc
diff --git a/lib/pace/Makefile.lammps b/lib/pace/Makefile.lammps
index f4cbeb8ffd..7e4513e36d 100644
--- a/lib/pace/Makefile.lammps
+++ b/lib/pace/Makefile.lammps
@@ -1,3 +1,3 @@
-pace_SYSINC =-I../../lib/pace/src/ML-PACE -I../../lib/pace/src/yaml-cpp/include
+pace_SYSINC =-I../../lib/pace/src/ML-PACE -I../../lib/pace/src/yaml-cpp/include -I../../lib/pace/src/wigner-cpp/include/wigner -DEXTRA_C_PROJECTIONS
 pace_SYSLIB = -L../../lib/pace/ -lpace -L../../lib/pace/src/yaml-cpp/ -lyaml-cpp
-pace_SYSPATH =
+pace_SYSPATH =
\ No newline at end of file