ggml/ex: calculate accuracy in graph, adapt MNIST (ggml/980)

ggml/src/ggml-cuda/argmax.cu

@@ -0,0 +1,79 @@
+#include "common.cuh"
+#include "argmax.cuh"
+#include "sum.cuh"
+
+#include <cstdint>
+
+static __global__ void argmax_f32(
+    const float * x, int32_t * dst, const int64_t ncols, const int64_t nrows) {
+
+    int argmax_thread = 0;
+    const int64_t row0 = (int64_t)blockIdx.x*WARP_SIZE;
+
+#pragma unroll
+    for (int64_t row1 = 0; row1 < WARP_SIZE; ++row1) {
+        const int64_t row = row0 + row1;
+
+        if (row >= nrows) {
+            break;
+        }
+
+        float maxval = -FLT_MAX;
+        int   argmax = -1;
+
+        for (int32_t col = threadIdx.x; col < ncols; col += WARP_SIZE) {
+            const float val        = x[row*ncols + col];
+            const int   bigger     = val > maxval;
+            const int   not_bigger = bigger ^ 0x00000001;
+
+            maxval = maxval*not_bigger + val*bigger;
+            argmax = argmax*not_bigger + col*bigger;
+        }
+
+#pragma unroll
+        for (int mask = 16; mask > 0; mask >>= 1) {
+            const float val        = __shfl_xor_sync(0xFFFFFFFF, maxval, mask, WARP_SIZE);
+            const int   col        = __shfl_xor_sync(0xFFFFFFFF, argmax, mask, WARP_SIZE);
+            const int   bigger     = val > maxval;
+            const int   not_bigger = bigger ^ 0x00000001;
+
+            maxval = maxval*not_bigger + val*bigger;
+            argmax = argmax*not_bigger + col*bigger;
+        }
+
+        const int store = row1 == threadIdx.x;
+        argmax_thread += store*argmax;
+    }
+
+    const int row = row0 + threadIdx.x;
+
+    if (row >= nrows) {
+        return;
+    }
+
+    dst[row] = argmax_thread;
+}
+
+void ggml_cuda_argmax(ggml_backend_cuda_context & ctx, ggml_tensor * dst) {
+    const ggml_tensor * src0 = dst->src[0];
+
+    GGML_ASSERT(src0->type == GGML_TYPE_F32);
+    GGML_ASSERT( dst->type == GGML_TYPE_I32);
+
+    GGML_ASSERT(ggml_is_contiguous(src0));
+
+    const int64_t ne00  = src0->ne[0];
+    const int64_t nrows = ggml_nrows(src0);
+
+    const float * src0_d = (const float *) src0->data;
+    int32_t     * dst_d  = (int32_t     *) dst->data;
+
+    cudaStream_t stream = ctx.stream();
+
+    const int64_t num_blocks = (nrows + WARP_SIZE - 1) / WARP_SIZE;
+
+    const dim3 blocks_dim(WARP_SIZE, 1, 1);
+    const dim3 blocks_num(num_blocks, 1, 1);
+
+    argmax_f32<<<blocks_num, blocks_dim, 0, stream>>>(src0_d, dst_d, ne00, nrows);
+}