Blas.cpp

#include <ATen/ATen.h>
#include <ATen/CPUFunctions.h>
#include <ATen/Dispatch.h>
#include <ATen/NamedTensorUtils.h>
#include <ATen/ScalarOps.h>

namespace at {
namespace meta {
TORCH_META_FUNC(addmv)(const Tensor &self, const Tensor &mat, const Tensor &vec, const Scalar& beta, const Scalar& alpha) {
  TORCH_CHECK((mat.dim() == 2 && vec.dim() == 1 && self.dim() <= 1),
    "vector + matrix @ vector expected, got ", self.dim(), ", ", mat.dim(), ", ", vec.dim());

  TORCH_CHECK(mat.size(1) == vec.size(0) && (mat.size(0) == self.numel() || self.numel() == 1),
     "size mismatch, got ", self.size(0), ", ", mat.size(0), "x", mat.size(1), ",", vec.size(0));
  auto names = at::namedinference::propagate_names_for_addmv(mat, vec, self);
  set_output(0, IntArrayRef(mat.sizes().data(), 1), {}, mat.options(), names);
  auto result = maybe_get_output(0);
  //this check can fire for inplace op only, for all other versions result is guaranteed to be correct size
  TORCH_CHECK(result.dim() == 1 && result.sizes()[0] == mat.sizes()[0], "output of addmv operation should be 1D with ",
  "size equal to mat.size(0), yet got output size ", result.sizes(), " and mat.size(0) ", mat.size(0));
}
}

namespace native {

template<typename scalar_t>
void gemv(char trans, int64_t m, int64_t n, scalar_t alpha, scalar_t *a, int64_t lda, scalar_t *x, int64_t incx, scalar_t beta, scalar_t *y, int64_t incy);

template<typename scalar_t>
scalar_t dot_impl(int64_t n, scalar_t *x, int64_t incx, scalar_t *y, int64_t incy);

template<typename scalar_t>
scalar_t vdot_impl(int64_t n, scalar_t *x, int64_t incx, scalar_t *y, int64_t incy);

constexpr inline bool lda_cond(int64_t m, int64_t n, int64_t lda) {
  return n == 1 || lda >= std::max<int64_t>(1L, m);
}




TORCH_IMPL_FUNC(addmv_out_cpu)(const Tensor &self, const Tensor &mat, const Tensor &vec, const Scalar& beta_, const Scalar& alpha_, const Tensor& result) {
  c10::MaybeOwned<Tensor> self_ = expand_size(self, {mat.size(0)});
  auto betaval = beta_.toComplexDouble();
  if (mat.numel() == 0) {
    // shortcut for an empty matrix
    // By definition, when beta==0, values in self should be ignored. nans and infs
    // should not propagate
    if (betaval == 0.0) {
      result.zero_();
    } else {
      at::cpu::mul_out(
          // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
          const_cast<Tensor&>(result),
          self,
          at::native::scalar_tensor(
              beta_, self.scalar_type(), c10::nullopt /* layout */, at::kCPU, c10::nullopt /* pin_memory */));
    }
  } else {
    if (!result.is_same(*self_) && betaval != 0.0) { //if beta is 0, result contents is ignored
      // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
      at::native::copy_(const_cast<Tensor&>(result), *self_);
    }
    if (result.numel() != 0) {
      auto r_stride = result.stride(0);
      AT_DISPATCH_ALL_TYPES_AND_COMPLEX_AND(kBFloat16, mat.scalar_type(), "addmv_impl_cpu", [&] {
        auto beta = beta_.to<scalar_t>();
        auto alpha = alpha_.to<scalar_t>();
        if (mat.stride(0) == 1 && lda_cond(mat.size(0), mat.size(1), mat.stride(1))) {
          gemv<scalar_t>('n', mat.size(0), mat.size(1), alpha, mat.data_ptr<scalar_t>(), mat.stride(1),
              vec.data_ptr<scalar_t>(), vec.stride(0), beta, result.data_ptr<scalar_t>(), r_stride);
        }
        else if (mat.stride(1) == 1 && lda_cond(mat.size(1), mat.size(0), mat.stride(0))) {
          gemv<scalar_t>('t', mat.size(1), mat.size(0), alpha, mat.data_ptr<scalar_t>(), mat.stride(0),
              vec.data_ptr<scalar_t>(), vec.stride(0), beta, result.data_ptr<scalar_t>(), r_stride);
        }
        else {
          Tensor cmat = mat.contiguous();
          gemv<scalar_t>('t', mat.size(1), mat.size(0), alpha, cmat.data_ptr<scalar_t>(), cmat.stride(0),
              vec.data_ptr<scalar_t>(), vec.stride(0), beta, result.data_ptr<scalar_t>(), r_stride);
        }
      });
    }
  }
}

Tensor &mv_out(const Tensor &self, const Tensor &vec, Tensor& result) {
  //self arg sent to addmv_out cannot be resized
  //here we use result as self argument for addmv, and result is user supplied and can be wrong size
  //it's not a hard error, because we allow resizing result, but it becomes a hard error
  //in addmv, because addmv expects self to satisfy proper conditions
  //to avoid this, supply correctly sized self, its contents doesn't matter because beta is 0
  if (result.dim() > 1 || (result.numel() != self.size(0) || result.numel() !=1)) {
    Tensor self_addmv = at::empty({self.size(0)}, self.options());
    return at::addmv_out(result, self_addmv, self, vec, 0, 1);
  }
  return at::addmv_out(result, result, self, vec, 0, 1);
}

Tensor mv(const Tensor &self, const Tensor &vec) {
  Tensor result = at::empty({self.size(0)}, self.options());
  //inplace version is more efficient if we can use it
  return at::addmv_(result, self, vec, 0, 1);
}

inline void dot_check(const Tensor& self, const Tensor& other) {
  TORCH_CHECK(
      self.dim() == 1 && other.dim() == 1,
      "1D tensors expected, but got ",
      self.dim(),
      "D and ",
      other.dim(),
      "D tensors");

  TORCH_CHECK(
      self.scalar_type() == other.scalar_type(),
      "dot : expected both vectors to have same dtype, but found ",
      self.scalar_type(),
      " and ",
      other.scalar_type());

  TORCH_CHECK(
      self.numel() == other.numel(),
      "inconsistent tensor size, expected tensor [",
      self.numel(),
      "] and src [",
      other.numel(),
      "] to have the same number of elements, but got ",
      self.numel(),
      " and ",
      other.numel(),
      " elements respectively");
}

Tensor dot(const Tensor &self, const Tensor &other){
  at::NoNamesGuard guard;

  dot_check(self, other);

  return AT_DISPATCH_ALL_TYPES_AND_COMPLEX_AND(at::ScalarType::Half, self.scalar_type(), "dot", [&] {
    Tensor result = at::empty({}, self.options());
    result.fill_(dot_impl<scalar_t>(self.numel(), self.data_ptr<scalar_t>(), self.stride(0), other.data_ptr<scalar_t>(), other.stride(0)));
    return result;
  });
}

Tensor vdot(const Tensor &self, const Tensor &other){
  at::NoNamesGuard guard;

  // Dispatch to `dot` for real dtypes.
  if (!self.is_complex()){
    return at::dot(self, other);
  }

  // For complex dtypes.
  dot_check(self, other);
  return AT_DISPATCH_COMPLEX_TYPES(self.scalar_type(), "vdot", [&] {
    Tensor result = at::empty({}, self.options());
    result.fill_(vdot_impl<scalar_t>(self.numel(), self.data_ptr<scalar_t>(), self.stride(0), other.data_ptr<scalar_t>(), other.stride(0)));
    return result;
  });

}

}}  // namespace at::native