Added host_conv_wrw for verification (#15)

* added host conv wrw

host/host_tensor/include/host_conv_wrw.hpp

+#pragma once
+#include "host_tensor.hpp"
+
+template <typename TOut,
+          typename TIn,
+          typename TWei,
+          typename ConvStrides,
+          typename ConvDilations,
+          typename InLeftPads,
+          typename InRightPads>
+void host_direct_convolution_backward_weights(
+    const Tensor<TOut>& out,
+    const Tensor<TIn>& in,
+    Tensor<TWei>& wei,
+    const ConvStrides& conv_strides,
+    const ConvDilations& conv_dilations,
+    const InLeftPads& in_left_pads,
+    const InRightPads&,
+    const ConvTensorLayout layout = ConvTensorLayout::NCHW)
+{
+    using namespace ck;
+
+    constexpr auto I0 = Number<0>{};
+    constexpr auto I1 = Number<1>{};
+    auto f_kcyx       = [&](auto k, auto c, auto y, auto x) {
+        double v = 0;
+        for(int n = 0; n < out.mDesc.GetLengths()[0]; ++n)
+        {
+            for(int ho = 0; ho < out.mDesc.GetLengths()[2]; ++ho)
+            {
+                int hi = ho * conv_strides[I0] + y * conv_dilations[I0] - in_left_pads[I0];
+                for(int wo = 0; wo < out.mDesc.GetLengths()[3]; ++wo)
+                {
+                    int wi = wo * conv_strides[I1] + x * conv_dilations[I1] - in_left_pads[I1];
+                    if(hi >= 0 && hi < in.mDesc.GetLengths()[2] && wi >= 0 &&
+                       wi < in.mDesc.GetLengths()[3])
+                    {
+                        v += static_cast<const double>(in(n, c, hi, wi)) *
+                             static_cast<const double>(out(n, k, ho, wo));
+                    }
+                }
+            }
+        }
+        wei(k, c, y, x) = v;
+    };
+
+    auto f_kyxc = [&](auto k, auto y, auto x, auto c) {
+        double v = 0;
+        for(int n = 0; n < out.mDesc.GetLengths()[0]; ++n)
+        {
+            for(int ho = 0; ho < out.mDesc.GetLengths()[1]; ++ho)
+            {
+                int hi = ho * conv_strides[I0] + y * conv_dilations[I0] - in_left_pads[I0];
+                for(int wo = 0; wo < out.mDesc.GetLengths()[2]; ++wo)
+                {
+                    int wi = wo * conv_strides[I1] + x * conv_dilations[I1] - in_left_pads[I1];
+                    if(hi >= 0 && hi < in.mDesc.GetLengths()[1] && wi >= 0 &&
+                       wi < in.mDesc.GetLengths()[2])
+                    {
+                        v += static_cast<const double>(in(n, hi, wi, c)) *
+                             static_cast<const double>(out(n, ho, wo, k));
+                    }
+                }
+            }
+        }
+        wei(k, y, x, c) = v;
+    };
+
+    if(layout == ConvTensorLayout::NCHW)
+    {
+        make_ParallelTensorFunctor(f_kcyx,
+                                   wei.mDesc.GetLengths()[0],
+                                   wei.mDesc.GetLengths()[1],
+                                   wei.mDesc.GetLengths()[2],
+                                   wei.mDesc.GetLengths()[3])(std::thread::hardware_concurrency());
+    }
+    else if(layout == ConvTensorLayout::NHWC)
+    {
+        make_ParallelTensorFunctor(f_kyxc,
+                                   wei.mDesc.GetLengths()[0],
+                                   wei.mDesc.GetLengths()[1],
+                                   wei.mDesc.GetLengths()[2],
+                                   wei.mDesc.GetLengths()[3])(std::thread::hardware_concurrency());
+    }
+    else
+    {
+        throw std::runtime_error("wrong! not supported layout");
+    }
+}