[FEA] add argminmax function #691
Description
Is your feature request related to a problem? Please describe.
MatX currently only has a argmin and argmax function, requiring separate kernel launches for each. If a user needs both the min and max, we should be able to submit a single kernel to calculate both (really all 4 outputs).
Describe the solution you'd like
A single call returns minValue, minIdx, maxValue, and maxIdx, such as the call below:
(matx::mtie(minVal, minIdx, maxVal, maxIdx) = matx::argminmax(inFlattened)).run();
This should work for batched reductions as well( outputs are all some higher dimension tensor, matching the sizes of inFlattened).
Describe alternatives you've considered
We can currently compute these results with separate calls, but this is less performant.