Describe the bug

When running ABACUS on a DSP, I discovered that it lacks native DSP computing support. Specifically, it relies on CPU-based FFT functions. Since the DSP shares the same function names with the CPU, setting the device to DSP causes certain functions within the recip2real module to incorrectly reference the CPU flag—which ultimately points to a non-functional dummy implementation.

Additionally, memory allocation errors occur when processing large systems if mt_malloc is used without a corresponding mt_free call.