Dimensions must be equal for 'MatMul' (op: 'MatMul') with input shape

 

a=tf.constant([[1,2],[1,2],[1,2],[1,2],[1,2]])
b=tf.constant([[4, 5],[1, 2],[1,2]])
print(a)
print(b)
c=tf.matmul(a,b)
print(c)

提示报错:ValueError: Dimensions must be equal, but are 2 and 3 for 'MatMul' (op: 'MatMul') with input shapes: [5,2], [3,2].

主要原因matmul是矩阵乘法的方法，要求第一个矩阵的第二维和第二个矩阵的第一维相同

改成

a=tf.constant([[1,2],[1,2],[1,2],[1,2],[1,2]])

b=tf.constant([[4, 5],[1, 2]])

c=tf.matmul(a,b)

print(c)

就可以了

如果类型不一样

a=tf.constant([[1,2],[1,2],[1,2],[1,2],[1,2]])
b=tf.constant([[4.0, 5.0],[1.0, 2.0]])
print(a)
print(b)
c=tf.matmul(a,b)
print(c)

TypeError: Input 'b' of 'MatMul' Op has type float32 that does not match type int32 of argument 'a'.

改成：

a=tf.constant([[1,2],[1,2],[1,2],[1,2],[1,2]],dtype=tf.float32)
b=tf.constant([[4.0, 5.0],[1.0, 2.0]],dtype=tf.float32)
print(a)
print(b)
c=tf.matmul(a,b)
print(c)