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layout shape migration

stuso

Hi All, i've written a simple script that grabs all shapes and changes the layerName and purpose as required (to map from one PDK to another). It works fine on small test cells. However i tried it out on a larger layout that has 52000 shapes (MPP's guard rings, looks llike each contact is a shape) & cadence crashes complaining of memory stack.

I think the code itself is efficient, but perhaps not:

foreach( shape_item cv~>shapes

 cond(
  (( nth( 0 shape_item~>lpp ) == "VTLN" && nth( 1 shape_item~>lpp )) == "drawing"
  shape_item~>layerName="OD" 
  shape_item~>purpose="drawing"
  )

nth( 0 shape_item~>lpp ) == "OD" && nth( 1 shape_item~>lpp )) == "drawing"

  shape_item~>layerName="NWELL" 
  shape_item~>purpose="drawing"
  )

...etc

 );end cond

);end foreach

So it sticks all the shapes in a list and then with the foreach it goes through each element of the list and change its layerName and purpose accordingly. If its not ok to have such a large list is it trivial to handle a list in say 500 elements at a time?

Or could it be that in layout land i am changing all these thousands of layer properties without a save and its too much data for the cadence to handle (or the undo stack becomes massive)?

Many thanks

Stu 

 

 

 

Parents
  • dmay

    I'm surprised you are running out of memory, since 52,000 doesn't seem that huge, but I do have several suggestions for performance improvement and simplicity of code.

    If your conditional is quite large (I'm assuming it is filled with many layer mappings), then you are making too many accesses to shape_item~>lpp. For example, if there are 20 checks in your conditional, they you are accessing this attribute 40 times if only the last item in the conditional matches. Generally speaking, try using car instead of nth(0 and cadr instead of nth(1. However, in this case I wouldn't do either. First of all, if you are not changing the purpose, then just check the layer name and save some trouble.

    (shape_item~>layerName == "VTLN" 
      shape_item~>layerName = "OD"
    )

    Again, you don't want to access that attribute more time than necessary, so try a case statement:

    case(shape_item~>layerName
      ("VTLN" 
        shape_item~>layerName = "OD")
      ("OD"
        shape_item~>layerName = "NWELL")
    )

    You could also loop through the cellview lpps attribute and then process the shapes one lpp at a time. Looks like Ted posted before me, so check out his solution.

    Derek

Reply
  • dmay

    I'm surprised you are running out of memory, since 52,000 doesn't seem that huge, but I do have several suggestions for performance improvement and simplicity of code.

    If your conditional is quite large (I'm assuming it is filled with many layer mappings), then you are making too many accesses to shape_item~>lpp. For example, if there are 20 checks in your conditional, they you are accessing this attribute 40 times if only the last item in the conditional matches. Generally speaking, try using car instead of nth(0 and cadr instead of nth(1. However, in this case I wouldn't do either. First of all, if you are not changing the purpose, then just check the layer name and save some trouble.

    (shape_item~>layerName == "VTLN" 
      shape_item~>layerName = "OD"
    )

    Again, you don't want to access that attribute more time than necessary, so try a case statement:

    case(shape_item~>layerName
      ("VTLN" 
        shape_item~>layerName = "OD")
      ("OD"
        shape_item~>layerName = "NWELL")
    )

    You could also loop through the cellview lpps attribute and then process the shapes one lpp at a time. Looks like Ted posted before me, so check out his solution.

    Derek

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