# tensorflow::ops::Dequantize Class Reference # tensorflow::ops::Dequantize `#include ` [Dequantize](https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize) the 'input' tensor into a float or bfloat16 [Tensor](https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/tensor#classtensorflow_1_1_tensor). ## Summary \[min_range, max_range\] are scalar floats that specify the range for the output. The 'mode' attribute controls exactly which calculations are used to convert the float values to their quantized equivalents. In 'MIN_COMBINED' mode, each value of the tensor will undergo the following:
``` if T == qint8: in[i] += (range(T) + 1)/ 2.0 out[i] = min_range + (in[i]* (max_range - min_range) / range(T)) ``` here `range(T) = numeric_limits::max() - numeric_limits::min()`
*MIN_COMBINED Mode Example* If the input comes from a [QuantizedRelu6](https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/quantized-relu6#classtensorflow_1_1ops_1_1_quantized_relu6), the output type is quint8 (range of 0-255) but the possible range of [QuantizedRelu6](https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/quantized-relu6#classtensorflow_1_1ops_1_1_quantized_relu6) is 0-6. The min_range and max_range values are therefore 0.0 and 6.0. [Dequantize](https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize) on quint8 will take each value, cast to float, and multiply by 6 / 255. Note that if quantizedtype is qint8, the operation will additionally add each value by 128 prior to casting. If the mode is 'MIN_FIRST', then this approach is used: ``` num_discrete_values = 1 << (# of bits in T) range_adjust = num_discrete_values / (num_discrete_values - 1) range = (range_max - range_min) * range_adjust range_scale = range / num_discrete_values const double offset_input = static_cast(input) - lowest_quantized; result = range_min + ((input - numeric_limits::min()) * range_scale) ```
If the mode is `SCALED`, dequantization is performed by multiplying each input value by a scaling_factor. (Thus an input of 0 always maps to 0.0). The scaling_factor is determined from `min_range`, `max_range`, and `narrow_range` in a way that is compatible with `QuantizeAndDequantize{V2|V3}` and `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/quantize-v2#classtensorflow_1_1ops_1_1_quantize_v2`, using the following algorithm: ```` const int min_expected_T = std::numeric_limits::min() + (narrow_range ? 1 : 0); const int max_expected_T = std::numeric_limits::max(); const float max_expected_T = std::numeric_limits::max(); ``` const float scale_factor = (std::numeric_limits::min() == 0) ? (max_range / max_expected_T) : std::max(min_range / min_expected_T, max_range / max_expected_T); ``` Arguments: - scope: A https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/scope#classtensorflow_1_1_scope object - min_range: The minimum scalar value possibly produced for the input. - max_range: The maximum scalar value possibly produced for the input. Optional attributes (see `https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs#structtensorflow_1_1ops_1_1_dequantize_1_1_attrs`): - dtype: Type of the output tensor. Currently https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize supports float and bfloat16. If 'dtype' is 'bfloat16', it only supports 'MIN_COMBINED' mode. Returns: - `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/output#classtensorflow_1_1_output`: The output tensor. ### Constructors and Destructors `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1ace6411557abc00c6e59649720be7d579(const ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/scope#classtensorflow_1_1_scope & scope, ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/input#classtensorflow_1_1_input input, ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/input#classtensorflow_1_1_input min_range, ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/input#classtensorflow_1_1_input max_range)` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1afb71f46f9e4fc4922578ecd9116ad9b1(const ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/scope#classtensorflow_1_1_scope & scope, ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/input#classtensorflow_1_1_input input, ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/input#classtensorflow_1_1_input min_range, ::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/input#classtensorflow_1_1_input max_range, const https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs#structtensorflow_1_1ops_1_1_dequantize_1_1_attrs & attrs)` ### Public attributes `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1a917ce29fbec6ef49406db9a374bde9aa` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/operation#classtensorflow_1_1_operation` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1a5c4618ae3d058bcd8547217612f8f41e` `::https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/output#classtensorflow_1_1_output` ### Public functions `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1a4bdeb613e4b88880638a67528cbd01f0() const ` `::tensorflow::Node *` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1ab1b62ee39a382d6e124eb62156c05525() const ` ` `` ` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1ae01ee2df9b62f7729848ca15ed70e8fc() const ` ` `` ` ### Public static functions `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1ac0b7d9ea267e2c8719f63ff4434b5250(int64 x)` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs#structtensorflow_1_1ops_1_1_dequantize_1_1_attrs` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1aeb2c0e323cdc6f85554c6e03de751730(DataType x)` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs#structtensorflow_1_1ops_1_1_dequantize_1_1_attrs` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1ac9873b34c5c0eb36296e0fe726644fc9(StringPiece x)` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs#structtensorflow_1_1ops_1_1_dequantize_1_1_attrs` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize_1a4409107547aae6b42715813687850b35(bool x)` `https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs#structtensorflow_1_1ops_1_1_dequantize_1_1_attrs` ### Structs https://www.tensorflow.org/versions/r2.3/api_docs/cc/struct/tensorflow/ops/dequantize/attrs Optional attribute setters for https://www.tensorflow.org/versions/r2.3/api_docs/cc/class/tensorflow/ops/dequantize#classtensorflow_1_1ops_1_1_dequantize. Public attributes ### operation ``` Operation operation ``` ### output ``` ::tensorflow::Output output ``` Public functions ### Dequantize ``` Dequantize( const ::tensorflow::Scope & scope, ::tensorflow::Input input, ::tensorflow::Input min_range, ::tensorflow::Input max_range ) ``` ### Dequantize ``` Dequantize( const ::tensorflow::Scope & scope, ::tensorflow::Input input, ::tensorflow::Input min_range, ::tensorflow::Input max_range, const Dequantize::Attrs & attrs ) ``` ### node ``` ::tensorflow::Node * node() const ``` ### operator::tensorflow::Input ``` operator::tensorflow::Input() const ``` ### operator::tensorflow::Output ``` operator::tensorflow::Output() const ``` Public static functions ### Axis ``` Attrs Axis( int64 x ) ``` ### Dtype ``` Attrs Dtype( DataType x ) ``` ### Mode ``` Attrs Mode( StringPiece x ) ``` ### NarrowRange ``` Attrs NarrowRange( bool x ) ``` ````