np.triu(）, np.tril(）回傳上下三角矩陣
Example Code

• import numpy as np
• martix0 = np.arange(16).reshape((4,4))
• print('Originl matrix = ')
• print(martix0)
• print('diagonalized matrix with diag function = ', np.diag(martix0))
• print('Upper triangle of an matrix = '),
• print(np.triu(martix0))
• print('Lower triangle of an matrix = '),
• print(np.tril(martix0))

Note and Comments

• import numpy as np: 讀入numpy函式庫並命名為np
• np.arange(l).reshape((m,n)) 生成一個有l個元素的陣列, 並重新將此陣列重新分割爲m*n的矩陣
• np.diag(martix0) 對角化martix0, 並回傳對角元素
• np.trace(martix0) 對角化martix0, 並回傳跡(trace)
• np.triu(martix0) 回傳martix0的上三角矩陣
• np.tril(martix0) 回傳martix0的下三角矩陣

result