From ab5f0d1bcd71ab558f392f07bc6126da5191f09c Mon Sep 17 00:00:00 2001
From: Martin Diehl <mail@martin-diehl.net>
Date: Wed, 18 Aug 2021 22:18:08 +0200
Subject: [PATCH] no need for type conversion

---
 DAMASK_prerequisites.sh    |  2 +-
 python/damask/mechanics.py | 10 +++++-----
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/DAMASK_prerequisites.sh b/DAMASK_prerequisites.sh
index f0ae484e4..cff211cdb 100755
--- a/DAMASK_prerequisites.sh
+++ b/DAMASK_prerequisites.sh
@@ -74,7 +74,7 @@ echo PETSC_ARCH: $PETSC_ARCH
 echo PETSC_DIR: $PETSC_DIR
 echo
 echo $PETSC_DIR/$PETSC_ARCH/lib:
-/s $PETSC_DIR/$PETSC_ARCH/lib
+ls $PETSC_DIR/$PETSC_ARCH/lib
 echo
 echo $PETSC_DIR/$PETSC_ARCH/lib/petsc/conf/petscvariables:
 cat $PETSC_DIR/$PETSC_ARCH/lib/petsc/conf/petscvariables
diff --git a/python/damask/mechanics.py b/python/damask/mechanics.py
index c8519abad..0e160523b 100644
--- a/python/damask/mechanics.py
+++ b/python/damask/mechanics.py
@@ -257,18 +257,18 @@ def _polar_decomposition(T,requested):
     u, _, vh = _np.linalg.svd(T)
     R = _np.einsum('...ij,...jk',u,vh)
 
-    output = []
+    output = ()
     if 'R' in requested:
-        output.append(R)
+        output+=(R,)
     if 'V' in requested:
-        output.append(_np.einsum('...ij,...kj',T,R))
+        output+=(_np.einsum('...ij,...kj',T,R),)
     if 'U' in requested:
-        output.append(_np.einsum('...ji,...jk',R,T))
+        output+=(_np.einsum('...ji,...jk',R,T),)
 
     if len(output) == 0:
         raise ValueError('output needs to be out of V, R, U')
 
-    return tuple(output)
+    return output
 
 
 def _equivalent_Mises(T_sym,s):