Calculates the arithmetic mean of the elements of a matrix or a tensor.
input: A matrix or a tensor.
dimension: Specifies the dimension along which mean will be calculated. -1 means mean of all elements. For matrices, dimension 0 is rows (output will be 1-by-N) and 1 is columns (output will be N-by-1). For tensors, the specified dimension will be collapsed. For example, if the input is a 1×2×3×4 tensor and dimension is 1, the output will be a 1×3×4 tensor. If the size of the specified dimension is one, mean is equal to reshaping the tensor. If dimension is greater or equal to the number of dimensions in the input tensor or matrix, the output will be an empty tensor or matrix.
output: A matrix or a tensor of a floating point type. If dimension is -1, the output will be a scalar value.