25 lines
746 B
Fortran
25 lines
746 B
Fortran
program invert_simple
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implicit none
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integer, parameter :: n = 2
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double precision :: a(n,n)
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integer :: ipiv(n)
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double precision :: work(n) ! 最小工作空间（LWORK = N）
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integer :: info
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! 初始化一个简单的可逆矩阵: [[2, 1], [1, 2]]
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a(1,1) = 2.0d0; a(1,2) = 1.0d0
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a(2,1) = 1.0d0; a(2,2) = 2.0d0
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! LU 分解
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call DGETRF(n, n, a, n, ipiv, info)
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if (info /= 0) stop 'DGETRF failed'
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! 求逆（使用最小工作空间 LWORK = N）
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call DGETRI(n, a, n, ipiv, work, n, info)
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if (info /= 0) stop 'DGETRI failed'
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! 输出结果（应为 [[0.6667, -0.3333], [-0.3333, 0.6667]]）
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print *, 'Inverse:'
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print *, a(1,1), a(1,2)
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print *, a(2,1), a(2,2)
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end program |