]$  g77 -O3 MAIN.o write_output.o read_population.o write_population.o collide.o initial_conditions.o stream.o communicate.o -o lbm.x -I/usr/local/include -L/usr/local/lib -lmpich -lpthread -lrt
MAIN.o(.text+0x7a): In function `MAIN__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x252): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x273): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x294): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x2b5): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x2d6): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x2f7): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x318): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x339): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x35a): In function `read_population__':
: relocation truncated to fit: R_X86_64_PC32 directions_
read_population.o(.text+0x37b): In function `read_population__':
: additional relocation overflows omitted from the output
collect2: ld returned 1 exit status