This is the home of the runtime system source code.
Containing:
include/ 	all header files to be included in user's mpi program.
lib/ 		libraries to be linked to the tmpi executable.
src/		all the source code.
mpitrans	the MPI code convertor, only necessary for code containing 
		global variables.

Here is a simple example of how to use the tmpi library.
Suppose you have a file mm.c which is a simple matrix multiplication program
and doesn't contain global variables (if it does, the source program has to
be preprocessed by mpitrans), the Makefile looks as follows:

# TMPI to be modified to something appropriate.
TMPI= $(HOME)/thrMPI
TMPI_HOME=$(TMPI)/runtime
TMPI_INC=$(TMPI_HOME)/include
TMPI_LIB=$(TMPI_HOME)/lib
CFLAGS=-O3

.IGNORE :

SRC = mm

all : thr_$(SRC) MPI_$(SRC)

MPI_$(SRC): $(SRC).c makefile
        cc $(CFLAGS) -o MPI_$(SRC) $(SRC).c -lmpi -lm

thr_$(SRC) : $(SRC).c makefile
        cc $(CFLAGS) -Dmain=tmain -I$(TMPI_INC) $(SRC).c -o $@ -L$(TMPI_LIB) -lthrMPI.sproc -lthrMPI.defaults -lm

Look carefully the difference between how to build MPI_mm (mm using SGI MPI) and thr_mm (mm using TMPI). 
1) -Dmain=tmain is only necessary when the source program is not processed via mpitrans. (mpitrans will 
change the main function to tmain during the process.)
2) -L$(TMPI_LIB) -lthrMPI.defaults is also necessary only when the source program is not processed via
mpitrans. (mpitrans will generate several routines and libthrMPI.defaults.a contains the default version
of those routines.)
3) -L$(TMPI_LIB) -lthrMPI.sproc links the program to sproc version of TMPI library. Currently TMPI
supports several thread packages and sproc is the default one.
4) -I$(TMPI_INC) We have to use our own version of mpi.h rather than system's version because lots
of data structures are different and function names are different. If you forget to add this option,
the compiler will generate errors during the linking phase.

