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xmgrace

Adding vertical line using "by function" not working in XMGrace


I have a large dataset of radius (y) v. time (x). I would like to add a vertical line at x = 1.656e12. When I add this using create new > by formula, I write:

"Stop at" = <maxiumum radius on y axis>
"Length" = 1.656e12
"Set type" = "XY"
X = 1.656e12
Y = $t

but no line shows. However, when I repeat this process for x = 2e12, it works. It seems that it doesn't work for any value below x = 2e12.

Any help would be appreciated, thanks.


Solution

  • The "length" field should contain an integer rather than a floating-point number. "Length" is just a short hand for "how many points should be in the final dataset". In this case you want to draw a straight line, and hence setting it to "2" should be enough. The reason why setting it to "2e12" works is that for some reason xmgrace converts 2e12 to 2.