FFTW::allocate: Memory Allocation for Fourier Transforms

FFTW::allocate is a function in the FFTW (Fastest Fourier Transform in the West) library that allocates memory for storing input and output data for a Fourier transform. It's used to allocate memory for an array of complex numbers, where each element has a real and imaginary part. The array's size is determined by the input data's dimensions and the desired transform. This function is typically used with other FFTW functions to perform a Fourier transform on a given dataset.