esys-escript

Inplace operations on Data object copies

Asked by Lutz Gross

Why does the script

  from esys.escript import *
  from esys.finley import Rectangle
  d=Rectangle()
  x=Scalar(1.,ContinuousFunction(d))
  y=x
  x+=1.
  print "x= ",x," y= ", y

return

  x = 2 and y = 2

and not x=2 and y=1 ?

Posted on behalf of Louise Olson-Kettle

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Lutz Gross (l-gross) said : 		#1

The statement y=x creates a shallow copy only. That means that the underlying data are not copied. Therefore an update of x will effect y. To make a deep copy you can use the copy method (which needs some revision) or - which is easier at this stage - use the statement y=x*1..

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Joel Fenwick (j-fenwick1) said : 		#2

It is better to use the copy method now.

so to make y an independent copy of x use:

y=x.copy()

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