A machine does not search for the right answer; it feels its way downhill through fog, measuring the slope of the loss function at each step and nudging the parameters against it, exactly as θ ← θ − lr·∇loss. A high learning rate makes every step leap past the bottom, the error curve turns jagged and can fly off into divergence; a low one inches the model along and burns through many epochs to bring the error down. The more a model wriggles to pass through every noisy point, the smaller its training error grows while its validation error climbs — that is overfitting.
A machine does not search for the right answer; it feels its way downhill through fog, measuring the slope of the loss function at each step and nudging the parameters against it, exactly as θ ← θ − lr·∇loss. A high learning rate makes every step leap past the bottom, the error curve turns jagged and can fly off into divergence; a low one inches the model along and burns through many epochs to bring the error down. The more a model wriggles to pass through every noisy point, the smaller its training error grows while its validation error climbs — that is overfitting.
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