An early framework for symbolic math and deep learning.
Theano was like a fussy old GPS for math. You drew the route, and it told the GPU race car where to floor it.
It powered early neural network research. Later tools learned from its symbolic graph style.
Autodiff
Theano used Autodiff to turn formulas into trainable gradients.
TensorFlow
TensorFlow carried on Theano's symbolic graph and compile idea.
Keras
Early Keras could use Theano as the engine to run models.
Deep Learning
Theano supported many early Deep Learning research experiments.