dvm_gauss_elimination.f90

来自「圆柱绕流问题的涡方法数值模拟（fortran源码）」· F90 代码 · 共 42 行

subroutine gs(A,B,N)
implicit none
INTEGER N,i,j,k,IMAX
real ::A(N,N),B(N),M(N,N)
real temp,MAX
       
do K=1,N-1
   MAX=ABS(A(K,K))
   IMAX=K
   do I=K+1,N
	  if(ABS(A(I,K)).GT.MAX)then
	  IMAX=I
	  MAX=ABS(A(I,K))
	  end if
   end do
   do J=1,N
      M(K,J)=A(K,J)
      A(K,J)=A(IMAX,J)
      A(IMAX,J)=M(K,J)
   end do
   temp=B(K)
   B(K)=B(IMAX)
   B(IMAX)=temp
   do I=K+1,N
	  M(I,K)=A(I,K)/A(K,K)
	  A(I,K)=0
	    do J=K+1,N
	    A(I,J)=A(I,J)-M(I,K)*A(K,J)
	    end do
   B(I)=B(I)-M(I,K)*B(K)
   end do
end do
  B(N)=B(N)/A(N,N)
  do K=N-1,1,-1
  temp=0.0
	do J=K+1,N
	   temp=temp+A(K,J)*B(J)
	end do
  B(K)=(B(K)-temp)/A(K,K)
  end do
  return
end subroutine