Logistic Regression (quick intro) back
Logistic Regression - one of the ways to build a linear model for the available training set data (X_i,Y_i): X=>Y.
On the other hand, this method (Linear Regression) can be regarded as a degenerate case of MultiLayer Fully Connectad Netwok.
As parameters LogisticRegression model has a matrix of weights with size NxK
and biases vector with size Nx1, where N - Size of feature vector (if feature
vector is gray-scale image with size LxL, then N=L*L), and K - is number of
classes.
Non-linearity in the model is selected as SoftMax: Y=SoftMax(W*X + B).
CrossEntropy is used as a loss function for multi categorical classification.
MNIST image database used as training set.
Next: 2.1 Logistic Regression with Theano