• Skip to main content
  • Skip to search
  • Skip to footer
Cadence Home
  • This search text may be transcribed, used, stored, or accessed by our third-party service providers per our Cookie Policy and Privacy Policy.

  1. Community Forums
  2. Custom IC Design
  3. Positioning the instances in Layout editor by using SKI...

Stats

  • Locked Locked
  • Replies 34
  • Subscribers 126
  • Views 32002
  • Members are here 0
This discussion has been locked.
You can no longer post new replies to this discussion. If you have a question you can start a new discussion

Positioning the instances in Layout editor by using SKILL

RFStuff
RFStuff over 12 years ago

 Dear All,

I am trying to place copies of an instance/object ( say a simple via ) with 'x' distance separation in X-direction.

Is there any in-built feature already available in IC5141 ?

Otherwise, is there any solution ( SKILL script) already posted in the forum ? I searched but couldn't find so.

The code needs three functions:

1) Find the cordianate of the OBJECT/INSTANCE ( this I have already found in the Forum)

2) Copy the object. For this what is the SKILL function ?

3) Paste the desired distance separation ( For palcing wht is the simple SKILL function)

Couls anybody please tell regarding this.

Kind Regards,

 

 

  • Cancel
Parents
  • Andrew Beckett
    Andrew Beckett over 12 years ago

    You can use setcar(nthcdr(N lst) newValue) to do this. Doesn't really need a specific function to do something so easy.

    In general however, using nth-type operators on lists is a bad way to do things. Lists are sequential data structures, and are not designed for random access operators (i.e. to be treated like arrays). Each time you ask for the Nth entry in a list, it has to start at the beginning and hop along N times until it reaches the entry.

    So, if you're doing a number of operations where you need access (read or write) to a numbered entry in the list, you may be better off doing:

    arr=listToVector(lst)
    arr[2]=56:23
    arr[6]=10:10
    ...
    lst=vectorToList(arr)

    In other words, converting the list into an array for the duration of your random access operations. For small lists, it's fine to use nth/nthcdr, but as soon as lists reach any kind of length, doing a repeated access by position can end up being very slow. The classic mistake I see people making is where they have a list and then want to (say) add up the values. They do:

    sum=0
    for(pos 0 length(lst)-1
      sum=sum+nth(pos lst)
    )

    That's OK if the list only has 5 entries, but if it had 1 million entries (say) it would take roughly half a billion list cell traversals (N(N+1)/2) whereas the correct way of doing it would be:

    sum=0
    foreach(val lst
      sum=sum+val
    )

    That's only a million list cell traversals - so half a million times fewer!

    Regards,

    Andrew.

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
Reply
  • Andrew Beckett
    Andrew Beckett over 12 years ago

    You can use setcar(nthcdr(N lst) newValue) to do this. Doesn't really need a specific function to do something so easy.

    In general however, using nth-type operators on lists is a bad way to do things. Lists are sequential data structures, and are not designed for random access operators (i.e. to be treated like arrays). Each time you ask for the Nth entry in a list, it has to start at the beginning and hop along N times until it reaches the entry.

    So, if you're doing a number of operations where you need access (read or write) to a numbered entry in the list, you may be better off doing:

    arr=listToVector(lst)
    arr[2]=56:23
    arr[6]=10:10
    ...
    lst=vectorToList(arr)

    In other words, converting the list into an array for the duration of your random access operations. For small lists, it's fine to use nth/nthcdr, but as soon as lists reach any kind of length, doing a repeated access by position can end up being very slow. The classic mistake I see people making is where they have a list and then want to (say) add up the values. They do:

    sum=0
    for(pos 0 length(lst)-1
      sum=sum+nth(pos lst)
    )

    That's OK if the list only has 5 entries, but if it had 1 million entries (say) it would take roughly half a billion list cell traversals (N(N+1)/2) whereas the correct way of doing it would be:

    sum=0
    foreach(val lst
      sum=sum+val
    )

    That's only a million list cell traversals - so half a million times fewer!

    Regards,

    Andrew.

    • Cancel
    • Vote Up 0 Vote Down
    • Cancel
Children
No Data

Community Guidelines

The Cadence Design Communities support Cadence users and technologists interacting to exchange ideas, news, technical information, and best practices to solve problems and get the most from Cadence technology. The community is open to everyone, and to provide the most value, we require participants to follow our Community Guidelines that facilitate a quality exchange of ideas and information. By accessing, contributing, using or downloading any materials from the site, you agree to be bound by the full Community Guidelines.

© 2025 Cadence Design Systems, Inc. All Rights Reserved.

  • Terms of Use
  • Privacy
  • Cookie Policy
  • US Trademarks
  • Do Not Sell or Share My Personal Information