And several matrix-vector product

* glm directly used as the Hadamard product (Hadamard product) of the representation symbols, the result for each component of the product. Hadamard product but the color integral equation approximation only established when (constant ratio of the spectral reflectance of the object at each wavelength is a constant).
There are represented using dot dot product, cross represents the cross product.
Another Kronecker product (Kronecker), also known as direct product or tensor product.