When a and b are 1-dimensional sequences, numpy.cov(a,b)[0][1] is equivalent to your cov(a,b). The 2×2 array returned by np.cov(a,b) has elements equal to (where, again, cov is the function you defined above.)
Answered by @hpaulj and @ForceBru in the comments. Missing a set of [] brackets.
The .T accesses the attribute T of the object, which happens to be a NumPy array. The T attribute is the transpose of the array, see the documentation. Apparently you are creating random coordinates in the plane. The output of multivariate_normal() might look like this: The transpose of this matrix is: which can be conveniently separated in x and y parts by sequence unpacking.
You are passing floats to a classifier which expects categorical values as the target vector. If you convert it to int it will be accepted as input (although it will be questionable if that’s the right way to do it). It would be better to convert your training scores by using scikit’s labelEncoder function. The … Read more
The error “only length-1 arrays can be converted to Python scalars” is raised when the function expects a single value but you pass an array instead. If you look at the call signature of np.int, you’ll see that it accepts a single value, not an array. In general, if you want to apply a function that … Read more