PROGMEM : pgm_read_float_near() equivalent for double? (Arduino Due)
Arduino Due (ARM Cortex-M3) doesn't need anything like PROGMEM as it has access into the flash memory in the same way as into the RAM. The const qualifier is enough to keep it in program memory only.

The AVR based boards like UNO needs PROGMEM because there are different instructions for fetching data from program memory and g++ is not very advanced in this way (some other compilers supports it directly - but usually expensive ones)