From c6149c230a1afd6e8a31954d3139d55544bd0b4a Mon Sep 17 00:00:00 2001
From: raj_mathe <raj.dahya@math.uni-leipzig.de>
Date: Tue, 14 Jun 2022 20:01:48 +0200
Subject: [PATCH] master > master: code py - utils, rel perm

---
 code/python/src/core/utils.py | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/code/python/src/core/utils.py b/code/python/src/core/utils.py
index 0585607..a565c9b 100644
--- a/code/python/src/core/utils.py
+++ b/code/python/src/core/utils.py
@@ -6,6 +6,7 @@
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 from src.thirdparty.code import *;
+from src.thirdparty.maths import *;
 from src.thirdparty.types import *;
 
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -14,6 +15,7 @@ from src.thirdparty.types import *;
 
 __all__ = [
     'iperm',
+    'permute_part',
 ];
 
 # ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -24,7 +26,22 @@ def iperm(order: List[int]) -> List[int]:
     '''
     Computes the inverse of a permutation.
     '''
-    n = len(order);
     perm = list(enumerate(order));
     uorder = list(map(lambda x: x[0], sorted(perm, key=lambda x: x[1])));
     return uorder;
+
+def permute_part(
+    x: np.ndarray,
+    indexes: List[int],
+    order: List[int],
+    in_place: bool = True,
+) -> np.ndarray:
+    '''
+    Permutes a part of a list by a relative permutation for that part of the list.
+    '''
+    if not in_place:
+        x = x[:];
+    part = x[indexes];
+    part[:] = part[order];
+    x[indexes] = part;
+    return x;