SAN FRANCISCO, March 13 : Amazon.com and Cerebras Systems on Friday said they have reached a deal to combine the two companies' computing chips in a new service aimed at speeding up chatbots, coding tools and other artificial intelligence services. Valued at $23.1 billion, Cerebras is a chip startup aiming to take on Nvidia by building a fundamentally different kind of AI chip that does not rely on expensive high-bandwidth memory as Nvidia's flagship chips do. Earlier this year, Cerebras signed