in source/geometry/GeometryStridedSlice.cpp [16:337]
virtual bool onCompute(const Op* op, const std::vector<Tensor*>& inputs, const std::vector<Tensor*>& outputs,
Context& context, CommandBuffer& res) const override {
Tensor* input = inputs[0];
// input haven't realized
auto output = outputs[0];
auto outputDes = TensorUtils::getDescribe(output);
outputDes->memoryType = Tensor::InsideDescribe::MEMORY_VIRTUAL;
const int inputDim = input->buffer().dimensions;
auto parameter = op->main_as_StridedSliceParam();
int32_t beginMask = parameter->beginMask();
int32_t endMask = parameter->endMask();
int32_t shrinkAxisMask = parameter->shrinkAxisMask();
int32_t ellipsisMask = parameter->ellipsisMask();
int32_t newAxisMask = parameter->newAxisMask();
int32_t fromType = parameter->fromType();
if (ellipsisMask && (ellipsisMask & (ellipsisMask - 1))) {
MNN_ERROR("only one non-zero bit is allowed in ellipsisMask\n");
return false;
}
MNN_ASSERT(inputs.size() >= 3 && inputs.size() <= 5);
Tensor *begin = inputs[1];
Tensor *end = inputs[2];
int32_t strideSize = begin->length(0);
MNN_ASSERT(begin->buffer().dimensions == end->buffer().dimensions);
int32_t inputShape[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t begins[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t ends[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t strides[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t axes[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t beginMasks[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t endMasks[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t shrinkAxisMasks[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t newAxisMasks[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t inputStride[MNN_MAX_TENSOR_DIM];
{
int stride = 1;
for (int i = input->buffer().dimensions - 1; i >= 0; --i) {
inputShape[i] = input->buffer().dim[i].extent;
inputStride[i] = stride;
stride *= inputShape[i];
}
}
for (int i = 0; i < inputDim; i++) {
inputShape[i] = input->length(i);
}
for (int i = 0; i < strideSize; i++) {
beginMasks[i] = beginMask & (1 << i);
}
for (int i = 0; i < strideSize; i++) {
endMasks[i] = endMask & (1 << i);
}
for (int i = 0; i < strideSize; i++) {
shrinkAxisMasks[i] = shrinkAxisMask & (1 << i);
}
for (int i = 0; i < strideSize; i++) {
newAxisMasks[i] = newAxisMask & (1 << i);
}
// broadcast begin end stride axis param
if (fromType == 1) {
Tensor *axis = nullptr;
if(inputs.size() >= 4) {
axis = inputs[3];
}
Tensor *step = nullptr;
if(inputs.size() == 5) {
step = inputs[4];
}
for(int i = 0; i < inputDim; i++) {
begins[i] = 0;
ends[i] = inputShape[i];
strides[i] = 1;
}
for (int i = 0; i < strideSize; i++) {
auto temp_axis = i;
if(axis != nullptr) {
temp_axis = axis->host<int>()[i];
temp_axis = temp_axis < 0 ? (temp_axis + inputDim) : temp_axis;
MNN_ASSERT(temp_axis < MNN_MAX_TENSOR_DIM);
}
if(step != nullptr) {
strides[temp_axis] = step->host<int>()[i];
}
auto shape = inputShape[temp_axis];
auto temp_value = begin->host<int>()[i];
temp_value = temp_value < 0 ? (temp_value + shape) : temp_value;
begins[temp_axis] = temp_value;
temp_value = end->host<int>()[i];
temp_value = temp_value < 0 ? (temp_value + shape) : temp_value;
ends[temp_axis] = temp_value;
}
strideSize = inputDim;
} else if(fromType == 0) {
Tensor *strided = nullptr;
if(inputs.size() >= 4) {
strided = inputs[3];
MNN_ASSERT(begin->buffer().dimensions == strided->buffer().dimensions);
}
// deal ellipsis, expand strides info
if (ellipsisMask > 0) {
int32_t beginMasksTmp[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t endMasksTmp[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t shrinkAxisMasksTmp[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t newAxisMasksTmp[MNN_MAX_TENSOR_DIM] = { 0 };
// expand stride info
int ellipsisPos = -1;
for (int i = 0; i < strideSize; i++) {
int temp = ellipsisMask & (1 << i);
if (temp != 0) {
ellipsisPos = i;
break;
}
}
MNN_ASSERT(ellipsisPos >= 0 && ellipsisPos < strideSize);
/*
Example: foo's dim is [2, 3, 4, 5, 6, 7], foo[0:2, :, 3:5, 3:6]:
1. strideSize = 4, inputDim = 6, ellipsis = 2(0010)
2. left part: 0:2, right part: 3:5, 3:6
3. expand: foo[0:2, 0:3, 0:4, 3:5, 3:6]
*/
int ellpsisSize = inputDim - strideSize, strideIdx = 0;
for (int i = 0; i < inputDim; i++) {
if (i == ellipsisPos) {
strideIdx++;
}
if (i >= ellipsisPos && i <= ellipsisPos + ellpsisSize) {
begins[i] = 0;
ends[i] = inputShape[i];
strides[i] = 1;
beginMasksTmp[i] = 0;
endMasksTmp[i] = 0;
shrinkAxisMasksTmp[i] = 0;
} else {
begins[i] = begin->host<int32_t>()[strideIdx];
ends[i] = end->host<int32_t>()[strideIdx];
if(strided != nullptr) {
strides[i] = strided->host<int32_t>()[strideIdx];
}
beginMasksTmp[i] = beginMasks[strideIdx];
endMasksTmp[i] = endMasks[strideIdx];
shrinkAxisMasksTmp[i] = shrinkAxisMasks[strideIdx];
newAxisMasksTmp[i] = newAxisMasks[strideIdx++];
}
}
for (int i = 0; i < inputDim; i++) {
beginMasks[i] = beginMasksTmp[i];
endMasks[i] = endMasksTmp[i];
shrinkAxisMasks[i] = shrinkAxisMasksTmp[i];
newAxisMasks[i] = newAxisMasksTmp[i];
}
strideSize = inputDim;
} else {
for (int i = 0; i < strideSize; i++) {
begins[i] = begin->host<int>()[i];
ends[i] = end->host<int>()[i];
strides[i] = strided->host<int>()[i];
}
}
}
int32_t beginShape[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t endShape[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t stridedShape[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t outputShape[MNN_MAX_TENSOR_DIM] = { 0 };
int32_t reverseDim = -1;
int32_t shapeNum = 0;
auto beginAndEndShapeLimit = [](int shape, int dimSize, bool exclusive) -> int {
int maxShape = dimSize - 1, minShape = -dimSize;
if (exclusive) {
++maxShape;
--minShape;
}
shape = (shape > maxShape ? maxShape : shape);
shape = (shape < minShape ? minShape : shape);
if (shape < 0) {
shape += dimSize;
}
return shape;
};
for (int i = 0; i < strideSize; i++) {
if (newAxisMasks[i] > 0) {
// ignore newAxis beacuse it is 1
continue;
}
stridedShape[shapeNum] = (shrinkAxisMasks[i] > 0 ? 1 : strides[i]);
if (stridedShape[shapeNum] < 0) {
reverseDim = i;
}
if (beginMasks[i] > 0) {
beginShape[shapeNum] = stridedShape[shapeNum] < 0 ? inputShape[shapeNum] - 1 : 0;
} else {
beginShape[shapeNum] = stridedShape[shapeNum] < 0 ? beginAndEndShapeLimit(begins[i], inputShape[shapeNum], false) :
std::min(inputShape[shapeNum], begins[i]);
}
if (beginShape[shapeNum] < 0) {
auto temp = -beginShape[shapeNum];
beginShape[shapeNum] = UP_DIV(temp, input->buffer().dim[i].extent) * input->buffer().dim[i].extent + beginShape[shapeNum];
}
if (endMasks[i] > 0) {
endShape[shapeNum] = stridedShape[shapeNum] < 0 ? -1 : inputShape[shapeNum];
} else {
endShape[shapeNum] = stridedShape[shapeNum] < 0 ? std::max(-1, std::min(inputDim, ends[i])) :
beginAndEndShapeLimit(ends[i], inputShape[shapeNum], true);
}
if (shrinkAxisMasks[i] == 0) {
if (stridedShape[shapeNum] > 0) {
int size = (endShape[shapeNum] - beginShape[shapeNum] - 1) / stridedShape[shapeNum] + 1;
outputShape[shapeNum] = size;
} else {
int size = (endShape[shapeNum] - beginShape[shapeNum] + 1) / stridedShape[shapeNum] + 1;
outputShape[shapeNum] = size;
}
} else {
outputShape[shapeNum] = 1;
}
shapeNum++;
}
int dealDims = shapeNum;
int dimensionRemained = input->dimensions() - dealDims;
for (int i = 0; i < dimensionRemained; i++) {
outputShape[shapeNum] = input->length(dealDims + i);
stridedShape[shapeNum] = 1;
beginShape[shapeNum] = 0;
shapeNum++;
}
int remainSize = 1;
int remainDims[MNN_MAX_TENSOR_DIM];
int remainDimSize = shapeNum - 3;
for (int i = 0; i < (int)shapeNum - 3; ++i) {
remainSize *= outputShape[i];
remainDims[i] = outputShape[i];
}
outputDes->regions.resize(remainSize);
int regionSize = shapeNum < 3 ? shapeNum : 3;
if (reverseDim >= 0) {
remainDimSize = reverseDim;
for (int i = 0; i < reverseDim; ++i) {
remainSize *= outputShape[i];
remainDims[i] = outputShape[i];
}
outputDes->regions.resize(remainSize);
regionSize = shapeNum - reverseDim;
MNN_ASSERT(regionSize <= 3);
}
int mod[MNN_MAX_TENSOR_DIM];
OpCommonUtils::computeStride(mod, remainDims, (int)remainDimSize);
int outputStrideTotal = 1;
int basicInputOffset = 0;
for (int i = 0; i < shapeNum - regionSize; ++i) {
basicInputOffset += inputStride[i] * beginShape[i];
}
for (int i = 0; i < regionSize; ++i) {
int pos = shapeNum - i - 1;
auto len = outputShape[pos];
basicInputOffset += inputStride[pos] * beginShape[pos];
outputStrideTotal *= len;
}
int coordinates[MNN_MAX_TENSOR_DIM];
for (int r = 0; r < remainSize; ++r) {
OpCommonUtils::unravelIndexHelper(coordinates, mod, remainDimSize, r);
int inputOffset = basicInputOffset;
for (int i = 0; i < remainDimSize; ++i) {
inputOffset += coordinates[i] * inputStride[i] * stridedShape[i];
}
auto& reg = outputDes->regions[r];
reg.dst.offset = r * outputStrideTotal;
reg.src.offset = inputOffset;
reg.origin = input;
for (int i = 0; i < regionSize; ++i) {
int pos = shapeNum - i - 1;
reg.size[3 - i - 1] = outputShape[pos];
reg.src.stride[3 - i - 1] = inputStride[pos] * stridedShape[pos];
}
reg.dst.stride[0] = reg.size[1] * reg.size[2];
reg.dst.stride[1] = reg.size[2];
reg.dst.stride[2] = 1;
}
if (fromType == 0 && inputs.size() == 5) {
auto write = inputs[4];
std::vector<int> shape(outputShape, outputShape + shapeNum);
if (write->shape() != shape) {
std::shared_ptr<Tensor> newTensor(new Tensor);
newTensor->buffer().type = write->buffer().type;
newTensor->buffer().dimensions = shapeNum;
for (int i = 0; i < shapeNum; i++) {
newTensor->setLength(i, outputShape[i]);
}
ConvertUtils::broadcastto(write, newTensor.get());
write = newTensor.get();
res.extras.emplace_back(newTensor);
}
for (auto& reg : outputDes->regions) {
auto tmp = reg.dst;
reg.dst = reg.src;
reg.src = tmp;
reg.origin = write;
}
Tensor::InsideDescribe::Region region;
region.size[2] = input->elementSize();
region.origin = input;
outputDes->regions.insert(outputDes->regions.begin(), region);
}
return true;
}