| |
| |
| ``mx.symbol.topk`` |
| ==================================== |
| |
| Description |
| ---------------------- |
| |
| Returns the indices of the top *k* elements in an input array along the given |
| axis (by default). |
| If ret_type is set to 'value' returns the value of top *k* elements (instead of indices). |
| In case of ret_type = 'both', both value and index would be returned. |
| The returned elements will be sorted. |
| |
| |
| **Example**:: |
| |
| |
| x = [[ 0.3, 0.2, 0.4], |
| [ 0.1, 0.3, 0.2]] |
| |
| // returns an index of the largest element on last axis |
| topk(x) = [[ 2.], |
| [ 1.]] |
| |
| // returns the value of top-2 largest elements on last axis |
| topk(x, ret_typ='value', k=2) = [[ 0.4, 0.3], |
| [ 0.3, 0.2]] |
| |
| // returns the value of top-2 smallest elements on last axis |
| topk(x, ret_typ='value', k=2, is_ascend=1) = [[ 0.2 , 0.3], |
| [ 0.1 , 0.2]] |
| |
| // returns the value of top-2 largest elements on axis 0 |
| topk(x, axis=0, ret_typ='value', k=2) = [[ 0.3, 0.3, 0.4], |
| [ 0.1, 0.2, 0.2]] |
| |
| // flattens and then returns list of both values and indices |
| topk(x, ret_typ='both', k=2) = [[[ 0.4, 0.3], [ 0.3, 0.2]] , [[ 2., 0.], [ 1., 2.]]] |
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| Usage |
| ---------- |
| |
| .. code:: r |
| |
| mx.symbol.topk(...) |
| |
| Arguments |
| ------------------ |
| |
| +----------------------------------------+------------------------------------------------------------+ |
| | Argument | Description | |
| +========================================+============================================================+ |
| | ``data`` | NDArray-or-Symbol. | |
| | | | |
| | | The input array | |
| +----------------------------------------+------------------------------------------------------------+ |
| | ``axis`` | int or None, optional, default='-1'. | |
| | | | |
| | | Axis along which to choose the top k indices. If not | |
| | | given, the flattened array is used. Default is | |
| | | -1. | |
| +----------------------------------------+------------------------------------------------------------+ |
| | ``k`` | int, optional, default='1'. | |
| | | | |
| | | Number of top elements to select, should be always smaller | |
| | | than or equal to the element number in the given axis. A | |
| | | global sort is performed if set k < | |
| | | 1. | |
| +----------------------------------------+------------------------------------------------------------+ |
| | ``ret.typ`` | {'both', 'indices', 'mask', 'value'},optional, | |
| | | default='indices'. | |
| | | | |
| | | The return type. | |
| | | "value" means to return the top k values, "indices" means | |
| | | to return the indices of the top k values, "mask" means to | |
| | | return a mask array containing 0 and 1. 1 means the top k | |
| | | values. "both" means to return a list of both values and | |
| | | indices of top k | |
| | | elements. | |
| +----------------------------------------+------------------------------------------------------------+ |
| | ``is.ascend`` | boolean, optional, default=0. | |
| | | | |
| | | Whether to choose k largest or k smallest elements. Top K | |
| | | largest elements will be chosen if set to | |
| | | false. | |
| +----------------------------------------+------------------------------------------------------------+ |
| | ``dtype`` | {'float16', 'float32', 'float64', 'int32', 'int64', | |
| | | 'uint8'},optional, | |
| | | default='float32'. | |
| | | | |
| | | DType of the output indices when ret_typ is "indices" or | |
| | | "both". An error will be raised if the selected data type | |
| | | cannot precisely represent the | |
| | | indices. | |
| +----------------------------------------+------------------------------------------------------------+ |
| | ``name`` | string, optional. | |
| | | | |
| | | Name of the resulting symbol. | |
| +----------------------------------------+------------------------------------------------------------+ |
| |
| Value |
| ---------- |
| |
| ``out`` The result mx.symbol |
| |
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| Link to Source Code: http://github.com/apache/incubator-mxnet/blob/1.6.0/src/operator/tensor/ordering_op.cc#L68 |
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