I am using Python to calculate the real FFT for a 2D array. I found that the real FFT function does not return an array with the same size as the input array, rather, it returns an array with the same size as the first axes and half of the size of the second axes or vise verse based on the axes order that we choose.
I attached the complex FFT, real FFT with axes order (0,1), and real FFT with axes order (1,0) of an array with size(1400x144). See the difference between the second and the third image. Any idea why that happens, and what does it mean in terms of the linear property of the FFT. Thanks