Fix index mechanism

Author: jhliu17

LUFactorization.py

@@ -13,17 +13,18 @@
     A = mats.Matrix(A)
     P, L, U = LUFactorization()(A)
 
+    print('The second column of A:\n', A[:, 2], sep='')
     print('\n', '*'*80, sep='')
     print('Execution Path:')
     result = A.forward(display=display_execution)
 
     print('\n', '*'*80, sep='')
     print('The LU Factorization result:')
-    print('P:\n', P)
-    print('L:\n', L)
-    print('U:\n', U)
+    print('P:\n', P, sep='')
+    print('L:\n', L, sep='')
+    print('U:\n', U, sep='')
 
     print('\n', '*'*80, sep='')
     print('Proof P * A = L * U:')
-    print('P * A:\n', P * A)
-    print('L * U:\n', L * U)
+    print('P * A:\n', P * A, sep='')
+    print('L * U:\n', L * U, sep='')

README.md

@@ -22,11 +22,16 @@ A = mats.Matrix(A) # get the matrix object from MatrixStitcher
 P, L, U = LUFactorization()(A) # apply LU Factorization on matrix A and get the factorization results
 
 # show the execution state of the matrix A
+print('The second column of A:\n', A[:, 2], sep='')
 print('Execution Path:')
 result = A.forward(display=True)
 ```
 Here is the execution result:
 ```
+The second column of A:
+array([[ 2.],
+       [ 8.],
+       [ 3.]])
 Execution Path:
 -> Origin matrix:
 array([[ 1.,  2., -3.],

matrixstitcher/backend.py

@@ -74,14 +74,20 @@ def __repr__(self):
         return self.matrix.__repr__()
 
     def __getitem__(self, key):
-        key = index_mechanism(*key)
+        if isinstance(key, (list, tuple)):
+            key = index_mechanism(*key)
+        else:
+            key = index_mechanism(*[key])
         data = self.matrix.__getitem__(key)
         # if not isinstance(data, np.ndarray):
         #     data = np.array(data).reshape(1)
         return Matrix(data, dtype=self.matrix.dtype)
 
     def __setitem__(self, key, value):
-        key = index_mechanism(*key)
+        if isinstance(key, (list, tuple)):
+            key = index_mechanism(*key)
+        else:
+            key = index_mechanism(*[key])
         self.matrix.__setitem__(key, value)
 
     def __add__(self, other):
@@ -220,13 +226,24 @@ def numpy(self):
 
 
 def index_mechanism(*key):
-    key = tuple(i - 1 if not isinstance(i, slice) else slice_mechanism(i) for i in key)
-    return key
+    new_key = []
+    # key = tuple(i - 1 if not isinstance(i, slice) else slice_mechanism(i) for i in key)
+    for i in key:
+        if isinstance(i, slice):
+            new_key.append(slice_mechanism(i))
+        else:
+            if i > 0:
+                new_key.append(i - 1)
+            elif i == 0:
+                raise Exception('Index from 0 is not vaild')
+            else:
+                new_key.append(i)
+    return tuple(new_key)
 
 
 def slice_mechanism(key: slice):
-    start = key.start - 1 if key.start is not None else None
-    stop = key.stop - 1 if key.stop is not None else None
+    start = index_mechanism(*[key.start])[0] if key.start is not None else None
+    stop = index_mechanism(*[key.stop])[0] if key.stop is not None else None
     step = key.step
     return slice(start, stop, step)