Change the working directory to the petsc directory:

cd path_to/petsc-x.x.x

	    

Set PETSC_DIR environment variable. For an sh-type shell:

PETSC_DIR=`pwd`; export PETSC_DIR      
	    

for a csh-type shell:

setenv PETSC_DIR `pwd`
	    

Choose system type and optimization level:

make PETSC_ARCH=os-type BOPT=O_c++
	    

where os-type is one of IRIX (for a 32-bit Irix build) or IRIX64 (for a 64 bit Irix build).

Configure PETSc:

./config/configure.py --with-mpi=0 --with-blas-lapack-dir=blas-lapack-lib-path
	    

for example:

Option --with-blas-lapack-dir applies if ATLAS (rather than BLAS) is used.

Build PETSc:

make all
make test