Max & Min primitive with 2-D numeric arrays

[David Boyd]

I posted this to Info-LabVIEW a week or so ago, I'll post it here as well. This has been confirmed by NI, and appears to have been introduced in LV6i or 6.1 (so it's hardly 7.1-specific):

To produce the bug, wire 2 2-D arrays of double to the X and Y inputs of a 'Max & Min' primitive (you know, the one with the measuring cups, found on the Comparisons palette). Leave the node configured to its default mode of 'Compare Elements'. Regardless of what you enter into the arrays, the 'Max(x,y)' output terminal will return the contents of the wire attached to 'X'. The 'Min(x,y)' output is correct. This problem appears to exist for all numeric datatypes of 2-D and higher order.

Others have pointed out that BD constant arrays are not subject to the buggy behavior. Also, if the 'X' input is coerced at the node (say, because it's been changed to integer or single-precision), the behavior is OK. It appears to be some sort of buffer reuse problem.

Thanks to Jesse 'Chip' Jones for the workaround suggestion of using two nodes, and inverting the inputs and outputs of the second node to use its 'Min' output for the 'Max'.

Dave