They are typically viewed as having some number of ''nodes'', each with one or more inputs and one output. These nodes are arranged into multiple ''layers'', with the outputs from one layer acting as the inputs to the next layer. The last layer has a single node, and its output is the output for the entire ''net''. The first layer's inputs are the inputs to the overall network. Each node contains a mathematical function indicating how it transforms its inputs into its output. Typically, neural networks are ''trained'' using a [[machine learning]] technique rather than having each node's function hand-programmed. This can lead to networks which perform their task adequately well, but without strong explanatory power for how they come to their decisions. | They are typically viewed as having some number of ''nodes'', each with one or more inputs and one output. These nodes are arranged into multiple ''layers'', with the outputs from one layer acting as the inputs to the next layer. The last layer has a single node, and its output is the output for the entire ''net''. The first layer's inputs are the inputs to the overall network. Each node contains a mathematical function indicating how it transforms its inputs into its output. Typically, neural networks are ''trained'' using a [[machine learning]] technique rather than having each node's function hand-programmed. This can lead to networks which perform their task adequately well, but without strong explanatory power for how they come to their decisions. |