parallelisation of lbfgs, change indentation, more comments (e3ed8d85) · Commits · 郑智淋 / lammps

src/SPIN/min_spin_oso_lbfgs_ls.cpp

+26 −8

Changes for src/SPIN/min_spin_oso_lbfgs_ls.cpp: 26 added lines, 8 removed lines.
Original line number	Diff line number	Diff line
		@@ -12,7 +12,7 @@
		------------------------------------------------------------------------- */

		/* ------------------------------------------------------------------------
		Contributing authors: Aleksei Ivanov (UI)
		Contributing authors: Aleksei Ivanov (University of Iceland)
		Julien Tranchida (SNL)

		Please cite the related publication:
		@@ -176,6 +176,7 @@ int MinSpinOSO_LBFGS_LS::iterate(int maxiter)
		double fmdotfm;
		int flag, flagall;
		double **sp = atom->sp;
		double der_e_cur_global = 0.0;

		if (nlocal_max < nlocal) {
		nlocal_max = nlocal;
		@@ -213,6 +214,8 @@ int MinSpinOSO_LBFGS_LS::iterate(int maxiter)
		for (int i = 0; i < 3 * nlocal; i++) {
		der_e_cur += g_cur[i] * p_s[i];
		}
		MPI_Allreduce(&der_e_cur, &der_e_cur_global, 1, MPI_DOUBLE, MPI_SUM, world);
		der_e_cur = der_e_cur_global;
		}

		if (use_line_search){
		@@ -353,7 +356,10 @@ void MinSpinOSO_LBFGS_LS::calc_gradient(double dts)
		}

		/* ----------------------------------------------------------------------
		search direction
		search direction:
		Limited-memory BFGS.
		See Jorge Nocedal and Stephen J. Wright 'Numerical
		Optimization' Second Edition, 2006 (p. 177)
		---------------------------------------------------------------------- */

		void MinSpinOSO_LBFGS_LS::calc_search_direction(int iter)
		@@ -629,9 +635,9 @@ void MinSpinOSO_LBFGS_LS::make_step(double c, double *energy_and_der)
		double rot_mat[9]; // exponential of matrix made of search direction
		double s_new[3];
		double **sp = atom->sp;
		double der_e_cur_global = 0.0;;

		for (int i = 0; i < nlocal; i++) {

		// scale the search direction

		for (int j = 0; j < 3; j++) p_scaled[j] = c * p_s[3 * i + j];
		@@ -653,10 +659,17 @@ void MinSpinOSO_LBFGS_LS::make_step(double c, double *energy_and_der)
		for (int i = 0; i < 3 * nlocal; i++) {
		der_e_cur += g_cur[i] * p_s[i];
		}
		MPI_Allreduce(&der_e_cur, &der_e_cur_global, 1, MPI_DOUBLE, MPI_SUM, world);
		der_e_cur = der_e_cur_global;

		energy_and_der[0] = ecurrent;
		energy_and_der[1] = der_e_cur;
		}

		/* ----------------------------------------------------------------------
		Calculate step length which satisfies approximate Wolfe conditions
		using the cubic interpolation
		------------------------------------------------------------------------- */

		int MinSpinOSO_LBFGS_LS::calc_and_make_step(double a, double b, int index)
		{
		@@ -671,6 +684,7 @@ int MinSpinOSO_LBFGS_LS::calc_and_make_step(double a, double b, int index)
		index++;

		if (awc(der_e_pr, eprevious, e_and_d[1], e_and_d[0]) \|\| index == 3){
		MPI_Bcast(&b,1,MPI_DOUBLE,0,world);

		for (int i = 0; i < 3 * nlocal; i++) {
		p_s[i] = b * p_s[i];
		@@ -689,6 +703,9 @@ int MinSpinOSO_LBFGS_LS::calc_and_make_step(double a, double b, int index)
		c2 = 3.0(f1-f0)/(rr)-(df1+2.0*df0)/(r);
		c3 = df0;

		// f(x) = c1 x^3 + c2 x^2 + c3 x^1 + c4
		// has minimum at alpha below. We do not check boundaries.

		alpha = (-c2 + sqrt(c2c2 - 3.0c1c3))/(3.0c1);
		if (alpha < 0.0) alpha = r/2.0;

		@@ -699,18 +716,19 @@ int MinSpinOSO_LBFGS_LS::calc_and_make_step(double a, double b, int index)
		}

		return 0;

		}


		/* ----------------------------------------------------------------------
		Approximate Wolfe conditions:
		William W. Hager and Hongchao Zhang
		SIAM J. optim., 16(1), 170-192. (23 pages)
		------------------------------------------------------------------------- */
		int MinSpinOSO_LBFGS_LS::awc(double der_phi_0, double phi_0, double der_phi_j, double phi_j){

		double eps = 1.0e-6;
		double delta = 0.1;
		double sigma = 0.9;

		if ((phi_j <= phi_0 + eps * fabs(phi_0)) &&
		((2.0delta - 1.0) der_phi_0 >= der_phi_j >= sigma * der_phi_0))
		if ((phi_j <= phi_0 + eps * fabs(phi_0)) && ((2.0delta - 1.0) der_phi_0 >= der_phi_j >= sigma * der_phi_0))
		return 1;
		else
		return 0;

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