在之前的博客中Python稀疏矩阵对角化库,我虽然介绍了一个python的库,可以用来计算稀疏矩阵的一些特定要求的本征矢量和本征值,但是python通常情况下是比较慢的,幸运的是这个功能最近正好的Julia中科成功的实现了,而且用法和python中几乎相同,这里正好就拿Julia来实验一下.
{:.info}

前言

对于julia同样是需要安装一个库才可以Arpack

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import Pkg
Pkg.add("Arpack")

安装完成之后,就可以使用了

实例(Julia)

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using Arpack,LinearAlgebra,DelimitedFiles
# ====================================
function matset(xn::Int64,ky::Float64)
    m0 = 1.5  # Effect mass
    mu = 0     # Chemical potential
    tx = 1.0
    ty = 1.0
    ax = 1.0
    ay = 1.0
    del0 = 0
    delx = 0.
    dely = -0.
    h = 0
    N = xn*8
    ham = zeros(ComplexF64,N,N)
    #-------------------------------------------------------------------------------
    g1 = zeros(ComplexF64,8,8)
    g2 = zeros(ComplexF64,8,8)
    g3 = zeros(ComplexF64,8,8)
    g4 = zeros(ComplexF64,8,8)
    g5 = zeros(ComplexF64,8,8)
    g6 = zeros(ComplexF64,8,8)
    # === Matrix settinf =====
    g1[1,1] = 1
    g1[2,2] = -1
    g1[3,3] = 1
    g1[4,4] = -1
    g1[5,5] = -1
    g1[6,6] = 1
    g1[7,7] = -1
    g1[8,8] = 1
    # ======
    g2[1,2] = 1
    g2[2,1] = 1
    g2[3,4] = -1
    g2[4,3] = -1
    g2[5,6] = 1
    g2[6,5] = 1
    g2[7,8] = -1
    g2[8,7] = -1
    # ======
    g3[1,2] = -im
    g3[2,1] = im
    g3[3,4] = -im
    g3[4,3] = im
    g3[5,6] = im
    g3[6,5] = -im
    g3[7,8] = im
    g3[8,7] = -im
    # ======
    g4[1,7] = -1
    g4[2,8] = -1
    g4[3,5] = 1
    g4[4,6] = 1
    g4[7,1] = -1
    g4[8,2] = -1
    g4[5,3] = 1
    g4[6,4] = 1
    # =======
    g5[1,1] = 1
    g5[2,2] = 1
    g5[3,3] = 1
    g5[4,4] = 1
    g5[5,5] = -1
    g5[6,6] = -1
    g5[7,7] = -1
    g5[8,8] = -1
    # ==============
    g6[1,3] = 1
    g6[2,4] = 1
    g6[3,1] = 1
    g6[4,2] = 1
    g6[5,7] = -1
    g6[6,8] = -1
    g6[7,5] = -1
    g6[8,6] = -1
    #--------------------------------------------------------------------------------
    for k in 0:xn-1
        if k == 0
            for m in 1:8
                for l in 1:8
                    ham[m,l] = (m0-ty*cos(ky))*g1[m,l] + (del0+dely*cos(ky))*g4[m,l] + ay*sin(ky)*g3[m,l]+ mu*g5[m,l] + h*g6[m,l]
                    ham[m,l+8] = (-tx*g1[m,l] + im*ax*g2[m,l] + delx*g4[m,l])/2
                end
            end
        elseif k == xn-1
            for m = 1:8
                for l = 1:8
                    ham[k*8 + m,k*8 + l] = (m0-ty*cos(ky))*g1[m,l] + (del0+dely*cos(ky))*g4[m,l] + ay*sin(ky)*g3[m,l]+ mu*g5[m,l] + h*g6[m,l]
                    ham[k*8 + m,k*8 + l - 8] = conj((-tx*g1[m,l] + im*ax*g2[m,l] + delx*g4[m,l])/2)
                end
            end
        else
            for m = 1:8
                for l = 1:8
                    ham[8*k + m,8*k + l] = (m0 - ty*cos(ky))*g1[m,l] + (del0+dely*cos(ky))*g4[m,l] + ay*sin(ky)*g3[m,l]+ mu*g5[m,l] + h*g6[m,l]
                    ham[8*k + m,8*k + l + 8] = (-tx*g1[m,l] + im*ax*g2[m,l])/2 + delx/2*g4[m,l]
                    ham[8*k + m,8*k + l - 8] = conj((-tx*g1[m,l] + im*ax*g2[m,l])/2 + delx/2*g4[m,l])
                end
            end
        end
    end
    return ham
end
# =============================================
ham = matset(1000,1.0)
ts = time()
val,vec = eigs(ham, nev = 10, which=:SM); # SM 取本征值大小最小的nev个本征值和本征矢量
tn = time()
f1 = open("time-julia.dat","w")
write(f1,"Time cost for Julia is ")
writedlm(f1,tn-ts)
close(f1)
#println(tn-ts)

实例(Fortran)

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    module param
    implicit none
    integer xn,yn,kn
    parameter(xn=1000,kn=30)
    integer,parameter::N=xn*8
    real,parameter::pi = 3.1415926535
    complex,parameter::im = (0.,1.0)  !虚数单位
!========== Hamiltonian ==========
    complex::H0(N,N) = 0
    complex::H1(N,N) = 0
    complex::H2(N,N) = 0
    complex::Ham(N,N) = 0
!=================================
    real m0   !Driac mass
    real tx,ty
    real ax,ay
    real del0,delx,dely
    complex::g1(8,8) = 0
    complex::g2(8,8) = 0
    complex::g3(8,8) = 0
    complex::g4(8,8) = 0
!================MKL===============
    integer::lda = N
    integer,parameter::lwmax=2*N+N**2
    real,allocatable::w(:)
    complex,allocatable::work(:)
    real,allocatable::rwork(:)
    integer,allocatable::iwork(:)
    integer lwork   ! at least 2*N+N**2
    integer lrwork    ! at least 1 + 5*N +2*N**2
    integer liwork   ! at least 3 +5*N
    integer info
    end module param
!================= PROGRAM START ============================
    program ex01
    use param
    integer m,l
    real ky
    real t1,t2
!====空间申请==================
    allocate(w(N))
    allocate(work(lwmax))
    allocate(rwork(1+5*N+2*N**2))
    allocate(iwork(3+5*N))
    call gamma()
!parameter value setting =====
    m0 = 1.5
    tx = 1.0
    ty = 1.0
    ax = 1.0
    ay = 1.0
    del0 = 0
    delx = 0.5
    dely = -0.5
    call cpu_time(t1)
    call en(1.0)
    call cpu_time(t2)
    open(20,file="time-fortran.dat")
    write(20,*)"Time cost for Fortran is ",t2-t1
    close(20)
    !===== Matrix set value ======
    ! open(1,file='en_band.dat')
    ! do m=-kn,kn
    !     ky=pi*m/kn
    !     call en(ky)
    !     !write(1,999)ky/pi,(w(i),i=1,N)
    !     write(1,999)ky,(w(i),i=1,N)
    ! enddo
    close(1)
999 format(241f11.5)
    stop 
    end program
!========================== PROGRAM END =====================
    subroutine en(ky)
    use param
    real ky
    call matrix(ky)
    call matrix_verify()
    call eigSol()
    end subroutine en
!======================== Pauli Matrix driect product============================
    subroutine gamma()
    use param
!=== Matrix settinf =====
    g1(1,1) = 1
    g1(2,2) = -1
    g1(3,3) = 1
    g1(4,4) = -1
    g1(5,5) = -1
    g1(6,6) = 1
    g1(7,7) = -1
    g1(8,8) = 1
!======
    g2(1,2) = 1
    g2(2,1) = 1
    g2(3,4) = -1
    g2(4,3) = -1
    g2(5,6) = 1
    g2(6,5) = 1
    g2(7,8) = -1
    g2(8,7) = -1
!======
    g3(1,2) = -im
    g3(2,1) = im
    g3(3,4) = -im
    g3(4,3) = im
    g3(5,6) = im
    g3(6,5) = -im
    g3(7,8) = im
    g3(8,7) = -im
!======
    g4(1,7) = -1
    g4(2,8) = -1
    g4(3,5) = 1
    g4(4,6) = 1
    g4(7,1) = -1
    g4(8,2) = -1
    g4(5,3) = 1
    g4(6,4) = 1
    return
    end subroutine gamma
!==========================================================
    subroutine matrix(ky)
    use param
    real ky
    integer m,l,k
    Ham = 0
!========== Positive energy ========
    do k = 0,xn-1
        if (k == 0) then ! Only right block in first line
            do m = 1,8
                do l = 1,8
                    Ham(m,l) = (m0-ty*cos(ky))*g1(m,l) + (del0+dely*cos(ky))*g4(m,l) + ay*sin(ky)*g3(m,l)
                    Ham(m,l+8) = (-tx*g1(m,l) + im*ax*g2(m,l))/2 + delx/2*g4(m,l)
                end do
            end do
        elseif ( k==xn-1 ) then ! Only left block in last line
            do m = 1,8
                do l = 1,8
                    Ham(k*8+m,k*8+l) = (m0-ty*cos(ky))*g1(m,l) + (del0+dely*cos(ky))*g4(m,l) + ay*sin(ky)*g3(m,l)
                    Ham(k*8+m,k*8+l-8) = conjg((-tx*g1(m,l) + im*ax*g2(m,l))/2) + conjg(delx/2*g4(m,l))
                end do
            end do
        else
            do m = 1,8
                do l = 1,8 ! k start from 1,matrix block from 2th row
                    Ham(8*k+m,8*k+l) = (m0 - ty*cos(ky))*g1(m,l) + (del0+dely*cos(ky))*g4(m,l) + ay*sin(ky)*g3(m,l)
                    Ham(8*k+m,8*k+l+8) = (-tx*g1(m,l) + im*ax*g2(m,l))/2 + delx/2*g4(m,l)
                    Ham(8*k+m,8*k+l-8) = conjg((-tx*g1(m,l) + im*ax*g2(m,l))/2) + conjg(delx/2*g4(m,l))
                end do
            end do
        end if
    end do
    return
    end subroutine matrix
!============================================================
    subroutine matrix_verify()
    use param
    integer i,j
    integer ccc
    ccc = 0
    
    do i = 1,N
        do j = 1,N
            if (Ham(i,j) .ne. conjg(Ham(j,i)))then
                open(16,file = 'hermitian.dat')
                ccc = ccc +1
                write(16,*)i,j
                write(16,*)Ham(i,j)
                write(16,*)Ham(j,i)
                write(16,*)"===================="
                write(*,*)"Ham isn't Hermitian."
                stop
            end if
        end do
    end do
    close(16)
    return
    end subroutine matrix_verify
!================= 矩阵本征值求解 ==============
    subroutine eigSol()
    use param
    integer m
    lwork = -1
    liwork = -1
    lrwork = -1
    call cheevd('V','Upper',N,Ham,lda,w,work,lwork &
        ,rwork,lrwork,iwork,liwork,info)
    lwork = min(2*N+N**2, int( work( 1 ) ) )
    lrwork = min(1+5*N+2*N**2, int( rwork( 1 ) ) )
    liwork = min(3+5*N, iwork( 1 ) )
    call cheevd('V','Upper',N,Ham,lda,w,work,lwork &
        ,rwork,lrwork,iwork,liwork,info)
    if( info .GT. 0 ) then
        open(11,file="mes.txt",status="unknown")
        write(11,*)'The algorithm failed to compute eigenvalues.'
        close(11)
    end if
    open(100,file="eigval.dat")
    do m = 1,N
        write(100,*)m,w(m)
    end do
    close(100)
    return
    end subroutine eigSol

实例(Python)

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import numpy as np
from numba import jit
from scipy.sparse.linalg import eigs, eigsh
import time
#==========================================================
def boundary(xn,yn,zn):
    # Arxiv-1909-10536
    # 构建不同方向hopping的索引矩阵
    nxy = xn*yn
    nxyz = xn*yn*zn
    bry = np.zeros((6,nxyz),dtype=int)
    for iz in range(zn):
        for iy in range(yn):
            for ix in range(xn):
                i = iz*nxy + iy*xn + ix
                bry[0,i] = i + 1  # x正向hopping
                if(ix==xn - 1):
                    bry[0,i] = bry[0,i] - xn
                bry[1,i] = i - 1  # x负向hopping
                if(ix==0):
                    bry[1,i] = bry[1,i] + xn
                bry[2,i] = i + xn  # y正向hopping
                if(iy==yn - 1):
                    bry[2,i] = bry[2,i] - nxy
                bry[3,i] = i - xn # y负向hopping
                if(iy==0):
                    bry[3,i] = bry[3,i] + nxy
                bry[4,i] = i + nxy # z正向hopping
                if(iz==zn - 1):
                    bry[4,i] = bry[4,i] - nxyz
                bry[5,i] = i - nxy # z负向hopping
                if(iz == 0):
                    bry[5,i] = bry[5,i] + nxyz
    return bry
#=============================================================
def phase(x,y):
    chi = 1.0
    return np.tanh(np.sqrt(1.0*x**2 + 1.0*y**2)/chi)*(x + 1j*y)/np.sqrt(1.0*x**2 + 1.0*y**2)
#===========================================================
def hamset(xn,yn,zn):
    nxy = xn*yn
    nxyz = xn*yn*zn
    N = nxyz*8
    m0 = -2.5
    t2 = 1.0

    t1z = 1.0
    t1x = 1.0
    t1y = 1.0

    t0x = 1.0
    t0y = 1.0
    t0z = 1.0

    del0 = 0.3
    delx = 0
    dely = 0
    mu = 0.1
    ham = np.zeros((N,N))*(1+0j)
    bry = boundary(xn,yn,zn)
    #-----------------------------
    for iz in range(zn):
        for iy in range(yn):
            for ix in range(xn):
                i = iz*nxy + iy*xn + ix
                #(1,1)
                ham[i,i] = m0 - mu
                if(ix != xn - 1):
                    ham[i,bry[0,i]] = t0x/2.0
                if(ix != 0):
                    ham[i,bry[1,i]] = t0x/2.0
                if(iy != yn - 1):
                    ham[i,bry[2,i]] = t0y/2.0
                if(iy != 0):
                    ham[i,bry[3,i]] = t0y/2.0
                if(iz != zn - 1):
                    ham[i,bry[4,i]] = t0z/2.0
                if(iz != 0):
                    ham[i,bry[5,i]] = t0z/2.0
                #(2,2)
                ham[nxyz + i,nxyz + i] = m0 - mu
                if(ix != xn - 1):
                    ham[nxyz + i,nxyz + bry[0,i]] = t0x/2.0
                if(ix != 0):
                    ham[nxyz + i,nxyz + bry[1,i]] = t0x/2.0
                if(iy != yn - 1):
                    ham[nxyz + i,nxyz + bry[2,i]] = t0y/2.0
                if(iy != 0):
                    ham[nxyz + i,nxyz + bry[3,i]] = t0y/2.0
                if(iz != zn - 1):
                    ham[nxyz + i,nxyz + bry[4,i]] = t0z/2.0
                if(iz != 0):
                    ham[nxyz + i,nxyz + bry[5,i]] = t0z/2.0
                #(3,3)
                ham[nxyz*2 + i,nxyz*2 + i] = -m0 - mu
                if(ix != xn - 1):
                    ham[nxyz*2 + i,nxyz*2 + bry[0,i]] = -t0x/2.0
                if(ix != 0):
                    ham[nxyz*2 + i,nxyz*2 + bry[1,i]] = -t0x/2.0
                if(iy != yn - 1):
                    ham[nxyz*2 + i,nxyz*2 + bry[2,i]] = -t0y/2.0
                if(iy != 0):
                    ham[nxyz*2 + i,nxyz*2 + bry[3,i]] = -t0y/2.0
                if(iz != zn - 1):
                    ham[nxyz*2 + i,nxyz*2 + bry[4,i]] = -t0z/2.0
                if(iz != 0):
                    ham[nxyz*2 + i,nxyz*2 + bry[5,i]] = -t0z/2.0
                #(4,4)
                ham[nxyz*3 + i,nxyz*3 + i] = -m0 - mu
                if(ix != xn - 1):
                    ham[nxyz*3 + i,nxyz*3 + bry[0,i]] = -t0x/2.0
                if(ix != 0):
                    ham[nxyz*3 + i,nxyz*3 + bry[1,i]] = -t0x/2.0
                if(iy != yn - 1):
                    ham[nxyz*3 + i,nxyz*3 + bry[2,i]] = -t0y/2.0
                if(iy != 0):
                    ham[nxyz*3 + i,nxyz*3 + bry[3,i]] = -t0y/2.0
                if(iz != zn - 1):
                    ham[nxyz*3 + i,nxyz*3 + bry[4,i]] = -t0z/2.0
                if(iz != 0):
                    ham[nxyz*3 + i,nxyz*3 + bry[5,i]] = -t0z/2.0
                #(1,4)
                if(ix != xn - 1):
                    ham[i,nxyz*3 + bry[0,i]] = -1j*t1x/2.0
                if(ix != 0):
                    ham[i,nxyz*3 + bry[1,i]] = 1j*t1x/2.0
                if(iy != yn - 1):
                    ham[i,nxyz*3 + bry[2,i]] = -t1y/2.0
                if(iy != 0):
                    ham[i,nxyz*3 + bry[3,i]] = t1x/2.0
                #(2,3)
                if(ix != xn - 1):
                    ham[nxyz + i,nxyz*2 + bry[0,i]] = -1j*t1x/2.0
                if(ix != 0):
                    ham[nxyz + i,nxyz*2 + bry[1,i]] = 1j*t1x/2.0
                if(iy != yn - 1):
                    ham[nxyz + i,nxyz*2 + bry[2,i]] = t1y/2.0
                if(iy != 0):
                    ham[nxyz + i,nxyz*2 + bry[3,i]] = -t1x/2.0
                #(3,2)
                if(ix != xn - 1):
                    ham[nxyz*2 + i,nxyz + bry[0,i]] = -1j*t1x/2.0
                if(ix != 0):
                    ham[nxyz*2 + i,nxyz + bry[1,i]] = 1j*t1x/2.0
                if(iy != yn - 1):
                    ham[nxyz*2 + i,nxyz + bry[2,i]] = -t1y/2.0
                if(iy != 0):
                    ham[nxyz*2 + i,nxyz + bry[3,i]] = t1x/2.0
                #(4,1)
                if(ix != xn - 1):
                    ham[nxyz*3 + i,bry[0,i]] = -1j*t1x/2.0
                if(ix != 0):
                    ham[nxyz*3 + i,bry[1,i]] = 1j*t1x/2.0
                if(iy != yn - 1):
                    ham[nxyz*3 + i,bry[2,i]] = t1y/2.0
                if(iy != 0):
                    ham[nxyz*3 + i,bry[3,i]] = -t1x/2.0
                #(1,3)
                if(iz != zn - 1):
                    ham[i,nxyz*2 + bry[4,i]] = t1z/(2j)
                if(iz != 0):
                    ham[i,nxyz*2 + bry[5,i]] = -t1z/(2j)
                if(ix != xn - 1):
                    ham[i,nxyz*2 + bry[0,i]] = -1j*t2/2.0
                if(ix != 0):
                    ham[i,nxyz*2 + bry[1,i]] = -1j*t2/2.0
                if(iy != yn - 1):
                    ham[i,nxyz*2 + bry[2,i]] = 1j*t2/2.0
                if(iy != 0):
                    ham[i,nxyz*2 + bry[3,i]] = 1j*t2/2.0
                #(2,4)
                if(iz != zn - 1):
                    ham[nxyz + i,nxyz*3 + bry[4,i]] = -t1z/(2j)
                if(iz != 0):
                    ham[nxyz + i,nxyz*3 + bry[5,i]] = t1z/(2j)
                if(ix != xn - 1):
                    ham[nxyz + i,nxyz*3 + bry[0,i]] = -1j*t2/2.0
                if(ix != 0):
                    ham[nxyz + i,nxyz*3 + bry[1,i]] = -1j*t2/2.0
                if(iy != yn - 1):
                    ham[nxyz + i,nxyz*3 + bry[2,i]] = 1j*t2/2.0
                if(iy != 0):
                    ham[nxyz + i,nxyz*3 + bry[3,i]] = 1j*t2/2.0
                #(3,1)
                if(iz != zn - 1):
                    ham[nxyz*2 + i,bry[4,i]] = t1z/(2j)
                if(iz != 0):
                    ham[nxyz*2 + i,bry[5,i]] = -t1z/(2j)
                if(ix != xn - 1):
                    ham[nxyz*2 + i,bry[0,i]] = 1j*t2/2.0
                if(ix != 0):
                    ham[nxyz*2 + i,bry[1,i]] = 1j*t2/2.0
                if(iy != yn - 1):
                    ham[nxyz*2 + i,bry[2,i]] = -1j*t2/2.0
                if(iy != 0):
                    ham[nxyz*2 + i,bry[3,i]] = -1j*t2/2.0
                #(4,2)
                if(iz != zn - 1):
                    ham[nxyz*3 + i,nxyz + bry[4,i]] = -t1z/(2j)
                if(iz != 0):
                    ham[nxyz*3 + i,nxyz + bry[5,i]] = t1z/(2j)
                if(ix != xn - 1):
                    ham[nxyz*3 + i,nxyz + bry[0,i]] = 1j*t2/2.0
                if(ix != 0):
                    ham[nxyz*3 + i,nxyz + bry[1,i]] = 1j*t2/2.0
                if(iy != yn - 1):
                    ham[nxyz*3 + i,nxyz + bry[2,i]] = -1j*t2/2.0
                if(iy != 0):
                    ham[nxyz*3 + i,nxyz + bry[3,i]] = -1j*t2/2.0
                # ---------------------------------------------------
                 #i = iz*nxy + iy*xn + ix
                if(iy == int(yn/2)& iz == int(zn/2)):
                    phi = 0.0
                else:
                    phi = phase(iy - yn/2,iz - yn/2)
                #(1,6)
                ham[i,nxyz*5 + i] = -1j*del0*phi
                if(ix != xn - 1):
                    ham[i,nxyz*5 + bry[0,i]] = -1j*delx
                if(ix != 0):
                    ham[i,nxyz*5 + bry[1,i]] = -1j*delx
                if(iy != yn - 1):
                    ham[i,nxyz*5 + bry[2,i]] = -1j*dely
                if(ix != 0):
                    ham[i,nxyz*5 + bry[3,i]] = -1j*dely
                #(6,1)
                ham[nxyz*5 + i,i] = 1j*del0*phi
                if(ix != xn - 1):
                    ham[nxyz*5 + i,bry[0,i]] = 1j*delx
                if(ix != 0):
                    ham[nxyz*5 + i,bry[1,i]] = 1j*delx
                if(iy != yn - 1):
                    ham[nxyz*5 + i,bry[2,i]] = 1j*dely
                if(ix != 0):
                    ham[nxyz*5 + i,bry[3,i]] = 1j*dely
                #(5,2)
                ham[nxyz*4 + i,nxyz + i] = 1j*del0*phi
                if(ix != xn - 1):
                    ham[nxyz*4 + i,nxyz + bry[0,i]] = 1j*delx
                if(ix != 0):
                    ham[nxyz*4 + i,nxyz + bry[1,i]] = 1j*delx
                if(iy != yn - 1):
                    ham[nxyz*4 + i,nxyz + bry[2,i]] = 1j*dely
                if(ix != 0):
                    ham[nxyz*4 + i,nxyz + bry[3,i]] = 1j*dely
                #(2,5)
                ham[nxyz + i,nxyz*4 + i] = -1j*del0*phi
                if(ix != xn - 1):
                    ham[nxyz + i,nxyz*4 + bry[0,i]] = -1j*delx
                if(ix != 0):
                    ham[nxyz + i,nxyz*4 + bry[1,i]] = -1j*delx
                if(iy != yn - 1):
                    ham[nxyz + i,nxyz*4 + bry[2,i]] = -1j*dely
                if(ix != 0):
                    ham[nxyz + i,nxyz*4 + bry[3,i]] = -1j*dely
                #(3,8)
                ham[nxyz*2 + i,nxyz*7 + i] = -1j*del0*phi
                if(ix != xn - 1):
                    ham[nxyz*2 + i,nxyz*7 + bry[0,i]] = -1j*delx
                if(ix != 0):
                    ham[nxyz*2 + i,nxyz*7 + bry[1,i]] = -1j*delx
                if(iy != yn - 1):
                    ham[nxyz*2 + i,nxyz*7 + bry[2,i]] = -1j*dely
                if(ix != 0):
                    ham[nxyz*2 + i,nxyz*7 + bry[3,i]] = -1j*dely
                #(8,3)
                ham[nxyz*7 + i,nxyz*2 + i] = 1j*del0*phi
                if(ix != xn - 1):
                    ham[nxyz*7 + i,nxyz*2 + bry[0,i]] = 1j*delx
                if(ix != 0):
                    ham[nxyz*7 + i,nxyz*2 + bry[1,i]] = 1j*delx
                if(iy != yn - 1):
                    ham[nxyz*7 + i,nxyz*2 + bry[2,i]] = 1j*dely
                if(ix != 0):
                    ham[nxyz*7 + i,nxyz*2 + bry[3,i]] = 1j*dely
    for m in range(4):
        for l in range(4):
            for k1 in range(nxyz):
                for k2 in range(nxyz):
                    ham[nxyz*4 + nxyz*m + k1,nxyz*4 + nxyz*l + k2] = np.conj(ham[nxyz*4 + nxyz*l + k2,nxyz*4 + nxyz*m + k1])
    return ham
#=================================================================
def test():
    t1 = time.time()
    ham = hamset(5,5,5)
    t2 = time.time()
    print("Hatset timing cost is  ",t2 - t1)
    t1 = time.time()
    #evals_all, evecs_all = eigh(X)
    #evals_large, evecs_large = eigsh(X, 3, which='LM')
    evals_be, evecs_be = eigsh(ham, 4, which='SM')
    t2 = time.time()
    print("Time cost is(s): %s"%(t2 - t1))

#==============================================
test()

结果对比

png

从时间对比上来看,利用Julia的效率还是比较高的.

但是这里有个问题,我在利用Fortran对角化的时候服务器的48核全部调用了,但是利用Julia的时候,仅仅调用了8核,所以从cpu用时来看是Julia快,但是真实的时间上看,还是Fortran用时短,我还没有搞清楚如何让Julia把服务器上所有的核都调用起来.
{:.warning}

总结

通常在计算的时候,需要的也仅仅是低能或者零能附近的本征矢量和本征值,所以通过Julia的这个库函数,可以大大的缩短求解时间,而且对于维数不大的矩阵,自己的电脑也同样可以计算,对角化上相对于Fortran还是可以节省一点时间.而且从现在Julia发展的趋势来看,还是很有亲和力的,起码我觉得在矢量操作运算方面比Fortran还是方便很多的,自己现在的很多计算也都是利用Julia来进行的,我自己也放弃了好好学python的想法,因为很多python的包,在Julia的环境下也慢慢的被包括了进来.
{:.success}

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