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39 #include "kernel_prune.h"
41 #include "gromacs/nbnxm/atomdata.h"
42 #include "gromacs/nbnxm/nbnxm_simd.h"
43 #include "gromacs/nbnxm/pairlist.h"
44 #include "gromacs/utility/gmxassert.h"
46 #ifdef GMX_NBNXN_SIMD_4XN
47 # define GMX_SIMD_J_UNROLL_SIZE 1
48 # include "kernel_common.h"
51 /* Prune a single nbnxn_pairtlist_t entry with distance rlistInner */
52 void nbnxn_kernel_prune_4xn(NbnxnPairlistCpu* nbl,
53 const nbnxn_atomdata_t* nbat,
54 gmx::ArrayRef<const gmx::RVec> shiftvec,
57 #ifdef GMX_NBNXN_SIMD_4XN
60 /* We avoid push_back() for efficiency reasons and resize after filling */
61 nbl->ci.resize(nbl->ciOuter.size());
62 nbl->cj.resize(nbl->cjOuter.size());
64 const nbnxn_ci_t* gmx_restrict ciOuter = nbl->ciOuter.data();
65 nbnxn_ci_t* gmx_restrict ciInner = nbl->ci.data();
67 const nbnxn_cj_t* gmx_restrict cjOuter = nbl->cjOuter.data();
68 nbnxn_cj_t* gmx_restrict cjInner = nbl->cj.data();
70 const real* gmx_restrict x = nbat->x().data();
72 const SimdReal rlist2_S(rlistInner * rlistInner);
74 /* Initialize the new list count as empty and add pairs that are in range */
77 const int nciOuter = nbl->ciOuter.size();
78 for (int i = 0; i < nciOuter; i++)
80 const nbnxn_ci_t* gmx_restrict ciEntry = &ciOuter[i];
82 /* Copy the original list entry to the pruned entry */
83 ciInner[nciInner].ci = ciEntry->ci;
84 ciInner[nciInner].shift = ciEntry->shift;
85 ciInner[nciInner].cj_ind_start = ncjInner;
87 /* Extract shift data */
88 int ish = (ciEntry->shift & NBNXN_CI_SHIFT);
91 SimdReal shX_S = SimdReal(shiftvec[ish][XX]);
92 SimdReal shY_S = SimdReal(shiftvec[ish][YY]);
93 SimdReal shZ_S = SimdReal(shiftvec[ish][ZZ]);
96 int scix = ci * STRIDE * DIM;
98 int scix = (ci >> 1) * STRIDE * DIM + (ci & 1) * (STRIDE >> 1);
101 /* Load i atom data */
102 int sciy = scix + STRIDE;
103 int sciz = sciy + STRIDE;
104 SimdReal ix_S0 = SimdReal(x[scix]) + shX_S;
105 SimdReal ix_S1 = SimdReal(x[scix + 1]) + shX_S;
106 SimdReal ix_S2 = SimdReal(x[scix + 2]) + shX_S;
107 SimdReal ix_S3 = SimdReal(x[scix + 3]) + shX_S;
108 SimdReal iy_S0 = SimdReal(x[sciy]) + shY_S;
109 SimdReal iy_S1 = SimdReal(x[sciy + 1]) + shY_S;
110 SimdReal iy_S2 = SimdReal(x[sciy + 2]) + shY_S;
111 SimdReal iy_S3 = SimdReal(x[sciy + 3]) + shY_S;
112 SimdReal iz_S0 = SimdReal(x[sciz]) + shZ_S;
113 SimdReal iz_S1 = SimdReal(x[sciz + 1]) + shZ_S;
114 SimdReal iz_S2 = SimdReal(x[sciz + 2]) + shZ_S;
115 SimdReal iz_S3 = SimdReal(x[sciz + 3]) + shZ_S;
117 for (int cjind = ciEntry->cj_ind_start; cjind < ciEntry->cj_ind_end; cjind++)
119 /* j-cluster index */
120 int cj = cjOuter[cjind].cj;
122 /* Atom indices (of the first atom in the cluster) */
123 # if UNROLLJ == STRIDE
124 int aj = cj * UNROLLJ;
127 int ajx = (cj >> 1) * DIM * STRIDE + (cj & 1) * UNROLLJ;
129 int ajy = ajx + STRIDE;
130 int ajz = ajy + STRIDE;
132 /* load j atom coordinates */
133 SimdReal jx_S = load<SimdReal>(x + ajx);
134 SimdReal jy_S = load<SimdReal>(x + ajy);
135 SimdReal jz_S = load<SimdReal>(x + ajz);
137 /* Calculate distance */
138 SimdReal dx_S0 = ix_S0 - jx_S;
139 SimdReal dy_S0 = iy_S0 - jy_S;
140 SimdReal dz_S0 = iz_S0 - jz_S;
141 SimdReal dx_S1 = ix_S1 - jx_S;
142 SimdReal dy_S1 = iy_S1 - jy_S;
143 SimdReal dz_S1 = iz_S1 - jz_S;
144 SimdReal dx_S2 = ix_S2 - jx_S;
145 SimdReal dy_S2 = iy_S2 - jy_S;
146 SimdReal dz_S2 = iz_S2 - jz_S;
147 SimdReal dx_S3 = ix_S3 - jx_S;
148 SimdReal dy_S3 = iy_S3 - jy_S;
149 SimdReal dz_S3 = iz_S3 - jz_S;
151 /* rsq = dx*dx+dy*dy+dz*dz */
152 SimdReal rsq_S0 = norm2(dx_S0, dy_S0, dz_S0);
153 SimdReal rsq_S1 = norm2(dx_S1, dy_S1, dz_S1);
154 SimdReal rsq_S2 = norm2(dx_S2, dy_S2, dz_S2);
155 SimdReal rsq_S3 = norm2(dx_S3, dy_S3, dz_S3);
157 /* Do the cut-off check */
158 SimdBool wco_S0 = (rsq_S0 < rlist2_S);
159 SimdBool wco_S1 = (rsq_S1 < rlist2_S);
160 SimdBool wco_S2 = (rsq_S2 < rlist2_S);
161 SimdBool wco_S3 = (rsq_S3 < rlist2_S);
163 wco_S0 = wco_S0 || wco_S1;
164 wco_S2 = wco_S2 || wco_S3;
165 wco_S0 = wco_S0 || wco_S2;
167 /* Putting the assignment inside the conditional is slower */
168 cjInner[ncjInner] = cjOuter[cjind];
175 if (ncjInner > ciInner[nciInner].cj_ind_start)
177 ciInner[nciInner].cj_ind_end = ncjInner;
182 nbl->ci.resize(nciInner);
183 nbl->cj.resize(ncjInner);
185 #else /* GMX_NBNXN_SIMD_4XN */
187 GMX_RELEASE_ASSERT(false, "4xN kernel called without 4xN support");
189 GMX_UNUSED_VALUE(nbl);
190 GMX_UNUSED_VALUE(nbat);
191 GMX_UNUSED_VALUE(shiftvec);
192 GMX_UNUSED_VALUE(rlistInner);
194 #endif /* GMX_NBNXN_SIMD_4XN */