Update jacobi_iteration_method.py

Changed comments, made variable names more understandable.
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Kamil 2023-08-13 19:06:59 +05:00 committed by GitHub
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@ -117,47 +117,38 @@ def jacobi_iteration_method(
"""
denom - a list of values along the diagonal
val - values of the last column of the table array
"""
denom = np.diag(coefficient_matrix)
"""
val_last - values of the last column of the table array
"""
val_last = table[:, -1]
"""
masks - boolean mask of all strings without diagonal
elements array coefficient_matrix
ttt - coefficient_matrix array values without diagonal elements
ind - column indexes for each row without diagonal elements
arr - list obtained by column indexes from the list init_val
the code below uses vectorized operations based on
the previous algorithm on loopss:
# Iterates the whole matrix for given number of times
for _ in range(iterations):
new_val = []
for row in range(rows):
temp = 0
for col in range(cols):
if col == row:
denom = table[row][col]
elif col == cols - 1:
val = table[row][col]
else:
temp += (-1) * table[row][col] * init_val[col]
temp = (temp + val) / denom
new_val.append(temp)
init_val = new_val
"""
denom = np.diag(coefficient_matrix)
val = table[:, -1]
masks = ~np.eye(coefficient_matrix.shape[0], dtype=bool)
ttt = coefficient_matrix[masks].reshape(-1, rows - 1)
"""
no_diag - coefficient_matrix array values without diagonal elements
"""
no_diag = coefficient_matrix[masks].reshape(-1, rows - 1)
"""
Here we get 'i_col' - these are the column numbers, for each row
without diagonal elements, except for the last column.
"""
i_row, i_col = np.where(masks)
ind = i_col.reshape(-1, rows - 1)
"""
'i_col' is converted to a two-dimensional list 'ind',
which will be used to make selections from 'init_val'
('arr' array see below).
"""
# Iterates the whole matrix for given number of times
for _ in range(iterations):
arr = np.take(init_val, ind)
temp = np.sum((-1) * ttt * arr, axis=1)
new_val = (temp + val) / denom
temp = np.sum((-1) * no_diag * arr, axis=1)
new_val = (temp + val_last) / denom
init_val = new_val
return new_val.tolist()