Fortran语言，do-end do循环，相互包含测试，自动性能优化

1）上代码

    !$omp parallel private(n, j, dx, dy, dz, r, a)do n = 1, nsteps!$omp dodo i = 0, nparticles - 1x_tmp(i) = x(i) + vx(i) * dty_tmp(i) = y(i) + vy(i) * dtz_tmp(i) = z(i) + vz(i) * dtdo j = 0, nparticles - 1dx = x(j) - x(i)dy = y(j) - y(i)dz = z(j) - z(i)R = sqrt(dx ** 2 + dy ** 2 + dz ** 2 + softening)a = G * m(j) / R ** 3 * dtvx(i) = vx(i) + a * dxvy(i) = vy(i) + a * dyvz(i) = vz(i) + a * dzend dodo j1 = 0, nparticles - 1dx = x(j1) - x(i)end dodo j2 = 0, nparticles - 1dx = x(j2) - x(i)do j3 = 0, nparticles - 1dx = x(j3) - x(i)end doend doend do!$omp dodo i = 0, nparticles - 1x(i) = x_tmp(i)y(i) = y_tmp(i)z(i) = z_tmp(i)do j4 = 0, nparticles - 1dx = x(j4) - x(i)do j = 0, nparticles - 1dx = x(j) - x(i)end doend doend dodo j = 0, nparticles - 1dx = x(j) - x(i)end do!$omp masterprint *, "n =", ndo i = 0, nparticles - 1print *, i, ":", x(i), y(i), z(i)end do!$omp end masterend do!$omp end parallel

2)

循环对：

 [[8, 19, -100], [22, 24, -100], [29, 31, -100], [26, 32, -100], [3, 33, -100], [43, 45, -100], [40, 46, -100], [36, 47, -100], [49, 51, -100], [55, 57, -100], [1, 59, -100]]

3）下面这个结果有错

 [[8, 19, 4], [22, 24, 0], [29, 31, 3], [26, 32, 1], [3, 33, 10], [43, 45, 6], [40, 46, 7], [36, 47, 10], [49, 51, 10], [55, 57, 10], [1, 59, -1]]

4）这个才是对的。

 [[8, 19, 4], [22, 24, 4], [29, 31, 3], [26, 32, 4], [3, 33, 10], [43, 45, 6], [40, 46, 7], [36, 47, 10], [49, 51, 10], [55, 57, 10], [1, 59, -1]]

目前看起来是对的。