向量点乘 (dot) 和对应分量相乘 (multiply) :
>>> aarray([1, 2, 3])>>> barray([ 1., 1., 1.])>>> np.multiply(a,b)array([ 1., 2., 3.])>>> np.dot(a,b)6.0
矩阵乘法 (dot) 和对应分量相乘 (multiply) :
>>> cmatrix([[1, 2, 3]])>>> dmatrix([[ 1., 1., 1.]])>>> np.multiply(c,d)matrix([[ 1., 2., 3.]])>>> np.dot(c,d)Traceback (most recent call last): File "<stdin>", line 1, in <module>ValueError: shapes (1,3) and (1,3) not aligned: 3 (dim 1) != 1 (dim 0)
写代码过程中,*表示对应分量相乘 (multiply) :
>>> a*barray([ 1., 2., 3.])>>> c*dTraceback (most recent call last): File "<stdin>", line 1, in <module> File "C:/ProgramData/Anaconda3/lib/site-packages/numpy/matrixlib/defmatrix.py", line 343, in __mul__ return N.dot(self, asmatrix(other))ValueError: shapes (1,3) and (1,3) not aligned: 3 (dim 1) != 1 (dim 0)
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