问题
Is there a way in numpy to do the following (or is there a general mathematical term for this):
Assume normal dot product:
M3[i,k] = sum_j(M1[i,j] * M2[j,k])
Now I would like to replace the sum by sum other operation, say the maximum:
M3[i,k] = max_j(M1[i,j] * M2[j,k])
As you can see it is completely parallel to the above, just we take max over all j and not the sum.
Other options could be min, prod, and whatever other operation that turns a sequence/set into a value.
回答1:
Normal dot product would be (using numpy broadcasting)
M3 = np.sum(M1[:, :, None] * M2[None, :, :], axis = 1)
You can do the same thing with any function you want that has an axis keyword.
M3 = np.max(M1[:, :, None] * M2[None, :, :], axis = 1)
来源：https://stackoverflow.com/questions/41164305/numpy-dot-product-with-max-instead-of-sum