From the documentation:
ZGETRI computes the inverse of a matrix using the LU factorization
computed by ZGETRF.
You need to run ZGETRF
first:
program test
Implicit none
integer,parameter::M=300
complex*16,allocatable,dimension(:,:)::A
complex*16,allocatable,dimension(:)::WORK
integer,allocatable,dimension(:)::IPIV
integer i,j,info,error
allocate(A(M,M),WORK(M),IPIV(M),stat=error)
if (error.ne.0)then
print *,"error:not enough memory"
stop
end if
!definition of the test matrix A
do i=1,M
do j=1,M
if(j.eq.i)then
A(i,j)=(1,0)
else
A(i,j)=0
end if
end do
end do
call ZGETRF(M,M,A,M,IPIV,info)
if(info .eq. 0) then
write(*,*)"succeded"
else
write(*,*)"failed"
end if
call ZGETRI(M,A,M,IPIV,WORK,M,info)
if(info .eq. 0) then
write(*,*)"succeded"
else
write(*,*)"failed"
end if
deallocate(A,IPIV,WORK,stat=error)
if (error.ne.0)then
print *,"error:fail to release"
stop
end if
end