text: /*******************************************************************************
  * Copyright 2017-2018 Intel Corporation
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *******************************************************************************/
  
  #include "src/common/dnnl_thread.hpp"
  
  #include "conv/conv_common.hpp"
  
  namespace conv {
  
  void compute_ref_fwd(const prb_t *p, dnn_mem_t &src_m, dnn_mem_t &wei_m,
          dnn_mem_t &bia_m, dnn_mem_t &dst_m) {
      if (p->alg == WINO && p->cfg[SRC].dt == dnnl_f32) {
          compute_wino_ref_fwd(p, src_m, wei_m, bia_m, dst_m);
      } else {
          compute_ref_direct_fwd(p, src_m, wei_m, bia_m, dst_m);
      }
  }
  
  void compute_ref_bwd_d(const prb_t *p, dnn_mem_t &diff_src_m, dnn_mem_t &wei_m,
          dnn_mem_t &bia_m, dnn_mem_t &diff_dst_m) {
      if (p->alg == WINO && p->cfg[SRC].dt == dnnl_f32) {
          compute_wino_ref_bwd_d(p, diff_src_m, wei_m, bia_m, diff_dst_m);
      } else {
          compute_ref_direct_bwd_d(p, diff_src_m, wei_m, bia_m, diff_dst_m);
      }
  }
  
  void compute_ref_bwd_w(const prb_t *p, dnn_mem_t &src_m, dnn_mem_t &diff_wei_m,
          dnn_mem_t &diff_bia_m, dnn_mem_t &diff_dst_m) {
      if (p->alg == WINO && p->cfg[SRC].dt == dnnl_f32) {
          compute_wino_ref_bwd_w(p, src_m, diff_wei_m, diff_bia_m, diff_dst_m);
      } else {
          compute_ref_direct_bwd_w(p, src_m, diff_wei_m, diff_bia_m, diff_dst_m);
      }
  }
  
  void compute_ref_direct_fwd(const prb_t *p, dnn_mem_t &src_m, dnn_mem_t &wei_m,
          dnn_mem_t &bia_m, dnn_mem_t &dst_m) {
      auto ker = [&](float &d, int64_t g, int64_t mb, int64_t oc, int64_t od,
                         int64_t oh, int64_t ow) {
          /* help compiler optimize the code */
          const int64_t G = p->g, OC = p->oc, IC = p->ic;
          const int64_t OCG = OC / G, ICG = IC / G;
          const int64_t ID = p->id, IH = p->ih, IW = p->iw;
          const int64_t KD = p->kd, KH = p->kh, KW = p->kw;
  
          for (int64_t ic = 0; ic < ICG; ++ic) {
              for (int64_t kd = 0; kd < KD; ++kd) {
                  const int64_t id = od * p->sd - p->pd + kd * (p->dd + 1);
                  if (id < 0 || id >= ID) continue;
                  for (int64_t kh = 0; kh < KH; ++kh) {
                      const int64_t ih = oh * p->sh - p->ph + kh * (p->dh + 1);
                      if (ih < 0 || ih >= IH) continue;
  
                      for (int64_t kw = 0; kw < KW; ++kw) {
                          const int64_t iw
                                  = ow * p->sw - p->pw + kw * (p->dw + 1);
                          if (iw < 0 || iw >= IW) continue;
  
                          int64_t src_off
                                  = (((mb * IC + g * ICG + ic) * ID + id) * IH
                                            + ih)
                                          * IW
                                  + iw;
                          int64_t wei_off
                                  = ((((g * OCG + oc) * ICG + ic) * KD + kd) * KH
                                            + kh)
                                          * KW
                                  + kw;
                          d += ((float *)src_m)[src_off]
                                  * ((float *)wei_m)[wei_off];
                      }
                  }
              }
          }
      };
  
      dnnl::impl::parallel_nd(p->g, p->mb, p->oc / p->g, p->od, p->oh, p->ow,
              [&](int64_t g, int64_t mb, int64_t oc, int64_t od, int64_t oh,
                      int64_t ow) {
                  const size_t dst_off = dst_off_f(p, mb, g, oc, od, oh, ow);
                  float &dst = ((float *)dst_m)[dst_off];
  
                  float conv_res = 0;
                  ker(conv_res, g, mb, oc, od, oh, ow);
  
                  if (p->dir & FLAG_BIA) {
                      const size_t bia_off = bia_off_f(p, g, oc);
                      conv_res += ((float *)bia_m)[bia_off];
                  }
  
                  maybe_scale(
                          conv_res, p->scales, g * p->oc / p->g + oc, p->attr);
                  maybe_post_ops(conv_res, dst, p->attr);
  
                  dst = conv_res;
              });
  }
  
  void compute_ref_direct_bwd_d(const prb_t *p, dnn_mem_t &diff_src_m,
          dnn_mem_t &wei_m, dnn_mem_t &bia_m, dnn_mem_t &diff_dst_m) {
      enum { precompute_size = 16 };
      const bool fast = MAX3(p->kd, p->kh, p->kw) <= precompute_size;
  
      /* pre-computes arrays of oh(ow) and kh(kw) for traversing in kernel */
      auto precompute_ok
              = [](int64_t i, int64_t O, int64_t K, int64_t S, int64_t P,
                        int64_t D, int64_t &num, int64_t *_o, int64_t *_k) {
                    assert(K <= precompute_size);
                    num = 0;
                    for (int64_t k = 0; k < K; ++k) {
                        int64_t o = i - k * (D + 1) + P;
                        if (o < 0 || o % S) continue;
                        o /= S;
                        if (o >= O) continue;
                        _k[num] = k;
                        _o[num] = o;
                        ++num;
                    }
                };
  
      auto ker_fast = [&](float &ds, int64_t g, int64_t mb, int64_t ic,
                              int64_t id, int64_t ih, int64_t iw) {
          int64_t kd[precompute_size], od[precompute_size], num_d;
          int64_t kh[precompute_size], oh[precompute_size], num_h;
          int64_t kw[precompute_size], ow[precompute_size], num_w;
          precompute_ok(id, p->od, p->kd, p->sd, p->pd, p->dd, num_d, od, kd);
          precompute_ok(ih, p->oh, p->kh, p->sh, p->ph, p->dh, num_h, oh, kh);
          precompute_ok(iw, p->ow, p->kw, p->sw, p->pw, p->dw, num_w, ow, kw);
  
          /* help compiler optimize the code */
          const int64_t G = p->g, OC = p->oc, IC = p->ic;
          const int64_t OCG = OC / G, ICG = IC / G;
          const int64_t KD = p->kd, KH = p->kh, KW = p->kw;
          const int64_t OD = p->od, OH = p->oh, OW = p->ow;
  
          for (int64_t oc = 0; oc < OCG; ++oc) {
              for_(int64_t d = 0; d < num_d; ++d)
              for_(int64_t h = 0; h < num_h; ++h)
              for (int64_t w = 0; w < num_w; ++w) {
                  int64_t dst_off
                          = (((mb * OC + g * OCG + oc) * OD + od[d]) * OH + oh[h])
                                  * OW
                          + ow[w];
                  int64_t wei_off
                          = ((((g * OCG + oc) * ICG + ic) * KD + kd[d]) * KH
                                    + kh[h])
                                  * KW
                          + kw[w];
                  ds += ((float *)diff_dst_m)[dst_off]
                          * ((float *)wei_m)[wei_off];
              }
          }
      };
  
      auto ker = [&](float &ds, int64_t g, int64_t mb, int64_t ic, int64_t id,
                         int64_t ih, int64_t iw) {
          for (int64_t oc = 0; oc < p->oc / p->g; ++oc) {
              for (int64_t kd = 0; kd < p->kd; ++kd) {
                  int64_t od = id - kd * (p->dd + 1) + p->pd;
                  if (od < 0 || od % p->sd) continue;
                  od /= p->sd;
                  if (od >= p->od) continue;
                  for (int64_t kh = 0; kh < p->kh; ++kh) {
                      int64_t oh = ih - kh * (p->dh + 1) + p->ph;
                      if (oh < 0 || oh % p->sh) continue;
                      oh /= p->sh;
                      if (oh >= p->oh) continue;
  
                      for (int64_t kw = 0; kw < p->kw; ++kw) {
                          int64_t ow = iw - kw * (p->dw + 1) + p->pw;
                          if (ow < 0 || ow % p->sw) continue;
                          ow /= p->sw;
                          if (ow >= p->ow) continue;
  
                          size_t dst_off = dst_off_f(p, mb, g, oc, od, oh, ow);
                          size_t wei_off = wei_off_f(p, g, oc, ic, kd, kh, kw);
                          ds += ((float *)diff_dst_m)[dst_off]
                                  * ((float *)wei_m)[wei_off];
                      }
                  }
              }
          }
      };
  
      dnnl::impl::parallel_nd(p->g, p->mb, p->ic / p->g, p->id, p->ih, p->iw,
              [&](int64_t g, int64_t mb, int64_t ic, int64_t id, int64_t ih,
                      int64_t iw) {
                  size_t src_off = src_off_f(p, mb, g, ic, id, ih, iw);
                  float &ds = ((float *)diff_src_m)[src_off];
                  float conv_res = 0;
                  if (fast)
                      ker_fast(conv_res, g, mb, ic, id, ih, iw);
                  else
                      ker(conv_res, g, mb, ic, id, ih, iw);
  
                  if (p->dir & FLAG_BIA) {
                      const size_t bia_off = (size_t)g * p->ic / p->g + ic;
                      conv_res += ((float *)bia_m)[bia_off];
                  }
                  maybe_scale(
                          conv_res, p->scales, g * p->ic / p->g + ic, p->attr);
                  maybe_post_ops(conv_res, ds, p->attr);
  
                  ds = conv_res;
              });
  }
  
  void compute_ref_bwd_weights(const prb_t *p, dnn_mem_t &src_m,
          dnn_mem_t &diff_wei_m, dnn_mem_t &diff_dst_m) {
      auto compute_bounds
              = [](int64_t I, int64_t O, int64_t k, int64_t S, int64_t P,
                        int64_t D, int64_t &o_s, int64_t &o_e) {
                    const float tmp = P - k * (D + 1);
                    o_s = MAX2(0, ceilf(tmp / S));
                    o_e = MIN2(O, ceilf((I + tmp) / S));
                };
  
      auto ker = [&](float &dw, int64_t g, int64_t oc, int64_t ic, int64_t kd,
                         int64_t kh, int64_t kw) {
          int64_t od_s, od_e, oh_s, oh_e, ow_s, ow_e;
          compute_bounds(p->id, p->od, kd, p->sd, p->pd, p->dd, od_s, od_e);
          compute_bounds(p->ih, p->oh, kh, p->sh, p->ph, p->dh, oh_s, oh_e);
          compute_bounds(p->iw, p->ow, kw, p->sw, p->pw, p->dw, ow_s, ow_e);
  
          for (int64_t mb = 0; mb < p->mb; ++mb) {
              for_(int64_t od = od_s; od < od_e; ++od)
              for_(int64_t oh = oh_s; oh < oh_e; ++oh)
              for (int64_t ow = ow_s; ow < ow_e; ++ow) {
                  const int64_t id = od * p->sd - p->pd + kd * (p->dd + 1);
                  const int64_t ih = oh * p->sh - p->ph + kh * (p->dh + 1);
                  const int64_t iw = ow * p->sw - p->pw + kw * (p->dw + 1);
  
                  size_t src_off = src_off_f(p, mb, g, ic, id, ih, iw);
                  size_t dst_off = dst_off_f(p, mb, g, oc, od, oh, ow);
                  dw += ((float *)diff_dst_m)[dst_off]
                          * ((float *)src_m)[src_off];
              }
          }
      };
  
      dnnl::impl::parallel_nd(p->g, p->oc / p->g, p->ic / p->g, p->kd, p->kh,
              p->kw,
              [&](int64_t g, int64_t oc, int64_t ic, int64_t kd, int64_t kh,
                      int64_t kw) {
                  size_t wei_off = wei_off_f(p, g, oc, ic, kd, kh, kw);
                  float &dw = ((float *)diff_wei_m)[wei_off];
                  dw = 0;
                  ker(dw, g, oc, ic, kd, kh, kw);
              });
  }
  
  void compute_ref_bwd_bias(
          const prb_t *p, dnn_mem_t &diff_bia_m, dnn_mem_t &diff_dst_m) {
      dnnl::impl::parallel_nd(p->g, p->oc / p->g, [&](int64_t g, int64_t oc) {
          size_t bia_off = bia_off_f(p, g, oc);
          double sum = 0;
  
          for_(int64_t mb = 0; mb < p->mb; ++mb)
          for_(int64_t od = 0; od < p->od; ++od)
          for_(int64_t oh = 0; oh < p->oh; ++oh)
          for (int64_t ow = 0; ow < p->ow; ++ow) {
              size_t dst_off = dst_off_f(p, mb, g, oc, od, oh, ow);
              sum += ((float *)diff_dst_m)[dst_off];
          }
          ((float *)diff_bia_m)[bia_off] = (float)sum;
      });
  }
  
  void compute_ref_direct_bwd_w(const prb_t *p, dnn_mem_t &src_m,
          dnn_mem_t &diff_wei_m, dnn_mem_t &diff_bia_m, dnn_mem_t &diff_dst_m) {
      compute_ref_bwd_weights(p, src_m, diff_wei_m, diff_dst_m);
      if (!(p->dir & FLAG_BIA)) return;
      compute_ref_bwd_bias(p, diff_bia_m, diff_dst_m);
  }
  
  } // namespace conv
  