diff options
Diffstat (limited to 'src/backends/tosaCommon/operatorMappings/TosaRescaleOperatorUtils.hpp')
| -rw-r--r-- | src/backends/tosaCommon/operatorMappings/TosaRescaleOperatorUtils.hpp | 211 |
1 files changed, 163 insertions, 48 deletions
diff --git a/src/backends/tosaCommon/operatorMappings/TosaRescaleOperatorUtils.hpp b/src/backends/tosaCommon/operatorMappings/TosaRescaleOperatorUtils.hpp index 1a4dd7aac3..56337cfdf4 100644 --- a/src/backends/tosaCommon/operatorMappings/TosaRescaleOperatorUtils.hpp +++ b/src/backends/tosaCommon/operatorMappings/TosaRescaleOperatorUtils.hpp @@ -11,12 +11,13 @@ inline void CreateRescaleTosaOperator(const std::string& inputName, const std::string& outputName, DType output_type, const std::vector<int32_t>& shape, - int32_t scale_multiplier, - int32_t scale_shift, + const std::vector<int32_t>& multipliers, + const std::vector<int32_t>& shifts, int32_t input_zp, int32_t output_zp, bool double_round, bool scale32, + bool per_channel, TosaSerializationOperator** op, TosaSerializationTensor** tensor) { @@ -25,15 +26,13 @@ inline void CreateRescaleTosaOperator(const std::string& inputName, throw armnn::Exception("CreateRescaleTosaOperator: nullptr op"); } - std::vector<int32_t> multipliers{scale_multiplier}; - std::vector<int32_t> shifts{scale_shift}; TosaRescaleAttribute attribute(input_zp, output_zp, multipliers, shifts, scale32, double_round, - false, // per_channel + per_channel, false, // input_unsigned false); // output_unsigned @@ -58,75 +57,191 @@ inline void CreateRescaleTosaOperator(const std::string& inputName, const std::string& outputName, DType output_type, const std::vector<int32_t>& shape, - double scale, + int32_t scale_multiplier, + int32_t scale_shift, int32_t input_zp, int32_t output_zp, bool double_round, bool scale32, + bool per_channel, TosaSerializationOperator** op, TosaSerializationTensor** tensor) { - // The code that follows is based on the behaviour specified in - // https://www.mlplatform.org/tosa/tosa_spec.html#_precision_scaling + const std::vector<int32_t> multipliers{scale_multiplier}; + const std::vector<int32_t> shifts{scale_shift}; + CreateRescaleTosaOperator(inputName, outputName, output_type, shape, multipliers, shifts, + input_zp, output_zp, double_round, scale32, per_channel, op, tensor); +} + +/// The following is taken from mlir/lib/Dialect/Tosa/Utils/QuantUtils.cpp in the LLVM project +/// From a scale value, generates multiplier and shift values where +/// mantissa is in [-1.0,-0.5] or [0.5, 1.0] such that +/// multiplier = mantissa*2^shift for 32-bit scaling. +static void ComputeMultiplierAndShiftTosaScale32(double scale, + int32_t &multiplier, + int32_t &shift) +{ + const double mantissa = std::frexp(scale, &shift); + auto shiftedM = std::round(mantissa * (int64_t(1) << 31)); + + // Can't be greater than 1.0. + if (!(shiftedM <= (int64_t(1) << 31))) + { + throw armnn::Exception("Shifted mantissa exceeds 32 signed bits"); + } - auto GetScaleParams = [](double scale, double& m, int32_t& n) + if (shiftedM == (int64_t(1) << 31)) { - m = 0; - n = 0; + shiftedM /= 2; + shift++; + } - double lastErr = 1e06; + // TOSA expects right shift to be positive, and embed (1 << 31) into right + // shift bits. + shift = (-shift) + 31; - const int32_t numExponents = 62; - const double start = 1.0; - const double end = 2.0; + if (!(shiftedM <= std::numeric_limits<int32_t>::max())) + { + throw armnn::Exception("Shifted mantissa exceeds 32-bit signed output type"); + } - // Slow iterative approach but running in Reference only - for (int32_t i = 0; i < numExponents; ++i) - { - double exp = 1.0 / (1 << i); - double currentM = scale / exp; // Find current m given value = currentM * exp - if ((currentM >= start) && (currentM < end)) - { - double value = currentM * exp; - double err = std::abs(scale - value); - if (err < lastErr) - { - // Take the m, n that minimize the error - n = i; - m = currentM; - lastErr = err; - } - } - } - }; + multiplier = static_cast<int32_t>(shiftedM); - auto GetMultiplierShiftByScale = [GetScaleParams](bool scale32, double scale, int32_t& multiplier, int32_t& shift) + // Shifting tops out at 62 bits. Right shift to make 62 bits the max. + // The limit of 62 on shift allows the shift to be decomposed as + // two right shifts of 31. + if (shift > 62) { - double m = 0; - int32_t n = 0; + // Shifting the multiplier by more than 32-bits is unnecessary. + multiplier = multiplier >> std::min<int32_t>(31, shift - 62); + shift = 62; + } +} - GetScaleParams(scale, m, n); +/// The following is taken from mlir/lib/Dialect/Tosa/Utils/QuantUtils.cpp in the LLVM project +/// From a scale value, generates multiplier and shift values where +/// mantissa is in [-1.0,-0.5] or [0.5, 1.0] such that +/// multiplier = mantissa*2^shift for 16-bit scaling. +static void ComputeMultiplierAndShiftTosaScale16(double scale, + int32_t &multiplier, + int32_t &shift) +{ + const double mantissa = std::frexp(scale, &shift); + auto shiftedM = std::round(mantissa * (int64_t(1) << 15)); - multiplier = (scale32) ? (1 << 30) * static_cast<int32_t>(m) : (1 << 14) * static_cast<int32_t>(m); - shift = (scale32) ? (30 + n) : (14 + n); - }; + // Can't be greater than 1.0. + if (!(shiftedM <= (int64_t(1) << 15))) + { + throw armnn::Exception("Shifted mantissa exceeds 16 signed bits"); + } + if (shiftedM == (int64_t(1) << 15)) + { + shiftedM /= 2; + shift++; + } + + // TOSA expects right shift to be positive and embed (1 << 15) into right + // shift bits. + shift = (-shift) + 15; + + if (!(shiftedM <= std::numeric_limits<int32_t>::max())) + { + throw armnn::Exception("Shifted mantissa exceeds 32-bit signed output type"); + } + + multiplier = static_cast<int32_t>(shiftedM); + + // Shifting tops out at 62 bits. Right shift to make 62 bits the max. + // The limit of 62 on shift allows the shift to be decomposed as + // two right shifts of 31. + if (shift > 62) + { + // Shifting the multiplier by more than 31-bits is unnecessary. + multiplier = multiplier >> std::min<int32_t>(31, shift - 62); + shift = 62; + } +} + +inline void CreateRescaleTosaOperator(const std::string& inputName, + const std::string& outputName, + DType output_type, + const std::vector<int32_t>& shape, + double scale, + int32_t input_zp, + int32_t output_zp, + bool double_round, + bool scale32, + TosaSerializationOperator** op, + TosaSerializationTensor** tensor) +{ int32_t multiplier; int32_t shift; - GetMultiplierShiftByScale(scale32, scale, multiplier, shift); + + if (scale32) + { + ComputeMultiplierAndShiftTosaScale32(scale, multiplier, shift); + } + else + { + ComputeMultiplierAndShiftTosaScale16(scale, multiplier, shift); + } + CreateRescaleTosaOperator(inputName, outputName, output_type, shape, multiplier, shift, - input_zp, output_zp, double_round, scale32, op, tensor); + input_zp, output_zp, double_round, scale32, false, op, tensor); } -inline void CreateFromInt32RescaleTosaOperator(const std::string& inputName, - const std::string& outputName, +inline void CreateRescaleTosaOperatorPerChannel(const std::string& inputName, + const std::string& outputName, DType output_type, const std::vector<int32_t>& shape, - double output_scale, + int32_t input_zp, int32_t output_zp, + bool double_round, + bool scale32, + double input_scale, + double output_scale, + const std::vector<float>& weight_scales, TosaSerializationOperator** op, TosaSerializationTensor** tensor) { - CreateRescaleTosaOperator(inputName, outputName, output_type, shape, - output_scale, 0, output_zp, true, true, op, tensor); + std::vector<int32_t> op_tensor_multipliers; + std::vector<int32_t> op_tensor_shifts; + op_tensor_multipliers.reserve(weight_scales.size()); + op_tensor_shifts.reserve(weight_scales.size()); + + for (const float& weight_scale : weight_scales) + { + double op_tensor_scale = (input_scale * weight_scale) / output_scale; + int32_t multiplier; + int32_t shift; + + if (scale32) + { + ComputeMultiplierAndShiftTosaScale32(op_tensor_scale, multiplier, shift); + } + else + { + ComputeMultiplierAndShiftTosaScale16(op_tensor_scale, multiplier, shift); + } + + op_tensor_multipliers.push_back(multiplier); + op_tensor_shifts.push_back(shift); + } + + CreateRescaleTosaOperator(inputName, outputName, output_type, shape, op_tensor_multipliers, op_tensor_shifts, + input_zp, output_zp, double_round, scale32, true, op, tensor); +} + +inline void CreateFromInt32RescaleTosaOperator(const std::string& inputName, + const std::string& outputName, + DType output_type, + const std::vector<int32_t>& shape, + double output_scale, + int32_t output_zp, + TosaSerializationOperator** op, + TosaSerializationTensor** tensor) +{ + CreateRescaleTosaOperator(inputName, outputName, output_type, shape, output_scale, + 0, output_zp, true, true, op, tensor); } |