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Allow graphs to display extended type values (i.e. create true EXT Graphs)

Status: Declined

Any idea that has received less than 3 kudos within 3 years after posting will be automatically declined.

This is one is probably just for me, as I described here.

The point is that if you connect EXT type data to a Graph (I tried XY Graphs, but it probably works the same for other graph types), although it will tell you on the diagram that it is an EXT type graph, what the front panel shows is that it behaves as a DBL type graph.

In other words, a value like 10^-4,000 (I just stumbled on a problem where I had to look into that range), will NOT be displayed on a so-called EXT graph. It will be cast to DBL and since DBL bottoms down at ~10^-340, the value is out of range.

Obviously, the same goes for VERY LARGE values.

And needless to say, you can't export the data to some other software, as it will be clipped to DBL, as discussed here.

5 Comments
Darren
Proven Zealot
Status changed to: Declined

Any idea that has received less than 3 kudos within 3 years after posting will be automatically declined.

DNatt, NI
X.
Trusted Enthusiast
Trusted Enthusiast

I guess, just as NI officially recommends to use LabVIEW 32 bit over 64 bit, they now recommend to use 64 bit floating point number over 128 bits.

TomOrr0W
Member

It is too late to kudo this idea, but I would have if it were not.

Could it be considered a bug that EXT graphs display as DBLs?  Note that copying data from an EXT graph to an EXT array control works as EXT data and not DBL data (tested in LV2017 with wiring an array of 5e-350, 6e-350, 7e-350, 8e-350 to a waveform graph, running the vi, right-clicking on the graph to copy data, and then right-clicking to paste data into an empty EXT array control).

TomOrr0W
Member

With a little more testing (changing - to + on the exponent in my previous statement), I found that you cannot type large values into an EXT constant.  5e+350 is coerced to INF in an EXT constant.  You can, however, type them into a EXT control (copying data from the control to the constant coerces to INF).

TomOrr0W
Member

The INF coercion appears to be related to the display formatting.  The data in the constant is still 5e+350 either way, but automatic formatting with 6 significant digits (the default for controls and indicators) displays 5e+350, while 13 significant digits (the default for constants) displays Inf.