问 Fortran和Matlab返回同一矩阵的不同特征值

EN

我试图通过对这个简单的矩阵进行对角化来学习如何使用LaPACK：

0.8147    0.9058    0.1270    0.9134
0.6324    0.0975    0.2785    0.5469
0.9575    0.9649    0.1576    0.9706
0.9572    0.4854    0.8003    0.1419

在matlab中，我只使用命令eig(mat)，得到输出：

ans =
    2.4021
   -0.0346
   -0.7158
   -0.4400

然而，当我试图编写一个简单的fortran程序来对同一个矩阵进行对角化时，我得到了不同的特征值：

      implicit none
  real*8, allocatable::dataMat(:,:),dataMatP(:,:),corMat(:,:),
 $   tempMat(:,:),corMat2(:,:)
  real*8, allocatable::matList(:),rawData(:)
  real*8, allocatable ::eig(:),diag(:),offdiag(:),tau(:),work(:)
  real*8 avg1,avg2,SD1,SD2,geneCorSum,genei,genej,temp
  integer i,j,k,numElements,info,lwork,numGenes,n,
 $   numExperiments,readsize,numAbsent,count,geneTolerance
  real*8 mean,std
  allocate(corMat(4,4))
corMat(1,1)=0.8147
corMat(1,2)=0.9058
corMat(1,3)=0.1270
corMat(1,4)=0.9134
corMat(2,1)=0.6234
corMat(2,2)=0.0975
corMat(2,3)=0.2785
corMat(2,4)=0.5469
corMat(3,1)=0.9575
corMat(3,2)=0.9649
corMat(3,3)=0.1576
corMat(3,4)=0.9706
corMat(4,1)=0.9572
corMat(4,2)=0.4854
corMat(4,3)=0.8003
corMat(4,4)=0.1419
  allocate(diag(n))
  allocate(offdiag(n-1))
  allocate(tau(n-1))
  allocate(work(1))
  call dsytrd('U',n,corMat,n,diag,offdiag,tau,
 $ work,-1,info)
  print*,"Returning from Blocksize calculation"
  if(info.eq.0) then
  print*,"Work value successfully calculated:",work(1)
  endif
  lwork=work(1)
  deallocate(work)
  allocate(work(max(1,lwork)))
  call dsytrd('U',n,corMat,n,diag,offdiag,tau,
 $ work,lwork,info)
  print*,"Returning from full SSYTRD"
  if(info.EQ.0) then
  print*,"Tridiagonal matrix calculated"
  endif
  call dsterf(n,diag,offdiag,info)
  if(info.EQ.0) then
    print*,"Matrix Diagonalized"
  endif
  do i=1,n
  print*,"lam=",i,diag(i)
  enddo
  deallocate(offdiag)
  deallocate(work)
  deallocate(tau)
  end

这给了我：

 lam= 1,  -1.0228376083545221
 lam= 2,  -0.48858533844019592
 lam= 3,  0.43828991894506536
 lam= 4,  2.2848330351691031

我是不是做错了什么来得到不同的特征值？