input: Numerical data stored in human readable text format, with a simple header to speed up loading. The header indicates the type of matrix as well as the number of rows and columns. For cubes, the header additionally specifies the number of slices. [auto_detect] 
output: arma_ascii
options: r a w _ a s c i i
options: r a w _ b i n a r y
options: a r m a _ a s c i i
options: a r m a _ b i n a r y
options: c s v _ a s c i i
options: h d f 5 _ b i n a r y
options: p g m _ b i n a r y
options: p p m _ b i n a r y