Fortran library for CSR format

This module can construct a sparce matrix with CSR format. The example is written in main.f90. Please see CMakeList.txt if you want to know how to link it.

How to test it.

mkdir build
cd build
cmake ..
./test

If you want to use MKL, use DMKLUSE flag:

mkdir build
cd build
cmake -DMKLUSE=on ..
./test

example

program main
    use csrmodule
    implicit none
    type(CSRcomplex)::H
    integer::N
    complex(8)::v,alpha,beta
    integer::i,j
    real(8)::mu,t
    complex(8),allocatable::x(:)
    complex(8),allocatable::y(:)
    complex(8),allocatable::ytemp(:)
    complex(8),allocatable::z(:)
    complex(8),allocatable::Hdense(:,:)
    complex(8),allocatable::ytemp2(:)

    N = 10
    v = -1d0
    t = -1d0
    mu = -1.5d0
    allocate(Hdense(2*N,2*N))

    H = CSRcomplex(2*N)
    do i = 1,N
        j = i
        v = -mu

        call H%set(v,i,j)
        Hdense(i,j) = v
        call H%set(-v,i+N,j+N)
        Hdense(i+N,j+N) = -v

        v = t
        j = i+1
        if (j > 0 .and. j < N+1) then
            call H%set(v,i,j)
            Hdense(i,j) = v
            call H%set(v,j,i)
            Hdense(j,i) = v

            call H%set(-v,i+N,j+N)
            Hdense(i+N,j+N) = -v
            call H%set(-v,j+N,i+N)
            Hdense(j+N,i+N) = -v
        end if

        j = i-1
        v =t

        if (j > 0 .and. j < N+1) then
            call H%set(v,i,j)
            Hdense(i,j) = v
            call H%set(v,j,i)
            Hdense(j,i) = v

            call H%set(-v,i+N,j+N)
            Hdense(i+N,j+N) = -v
            call H%set(-v,j+N,i+N)
            Hdense(j+N,i+N) = -v
        end if

        j = i+N
        v = 0.5d0
        call H%set(v,i,j)
        Hdense(i,j) = v
        call H%set(v,j,i)
        Hdense(j,i) = v

    end do

    call H%print()

    do i=1,N
        j = i+N
        v = 0.6d0
        call H%update(v,i,j)
        Hdense(i,j) = v
        call H%update(v,j,i)
        Hdense(j,i) = v


    end do
    call H%print()

    allocate(x(1:2*N))
    x = 0d0
    allocate(y(1:2*N))
    allocate(ytemp(1:2*N))
    allocate(ytemp2(1:2*N))
    y = 0d0
    ytemp = 0d0
    allocate(z(1:2*N))
    z(5) = 10d0
    x(3) = 1d0
    call H%matmul(x,y)
    !write(*,*) "matmul(x,y) ", y


    ytemp = H*x
    write(*,*) "H*x", ytemp

    ytemp2 = matmul(Hdense,x)
    do i=1,2*N
        write(*,*) i,ytemp(i),ytemp2(i)
    end do
    write(*,*) "diff = ",dot_product(ytemp-ytemp2,ytemp-ytemp2)/N




    alpha = 2d0
    beta = 3d0
    call H%matmul2(x,y,z,alpha,beta)
    !write(*,*) "y = alpha*A*x+beta*z",y


end program main

cometscome/fortran_csr

Fortran library for CSR format

example