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 Problem with dbLayerOr 

Last post Mon, Oct 19 2009 2:02 PM by Andrew Beckett. 3 replies.
Started by ToMWUT 17 Oct 2009 06:01 AM. Topic has 3 replies and 1478 views
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  • Sat, Oct 17 2009 6:01 AM

    • ToMWUT
    • Top 150 Contributor
    • Joined on Mon, Apr 20 2009
    • Warsaw, Poland
    • Posts 48
    • Points 795
    Problem with dbLayerOr Reply

    I've got an algorithm, which behaves a little strange since I've decided to use my function to perform OR operation on all objects which belongs to one list. The function I'm talking about looks like this:

    procedure(or_shapes(cv shape_list)

    prog((ret_shapes)

    if((length(shape_list)<2) then

    ts_ui_warning("ts_or_one_list_ver_2_shape_points" "Entry list smaller than 2 elements!")

    return(shape_list)

    );if

    ret_shapes=dbLayerOr(cv lppA shape_list)

    return(ret_shapes)

    );prog

    );procedure

    The lppA is a layer purpose pair which is a defined global. I'm also using an empty CV to perform the operation. From Cadence manual I figured out that this function should perform OR operations on all shapes given on shape_list. What I mean is operation which for overlapping regions of shapes in shape_list returns this overlapping region only once.

    And now the usage and the limitations. My algorithm in pseudo code looks something like this:

     

    in_area=Area(seed)

    seed=Oversize(seed, k)

    after_oversize=Area(seed)

    seed=or_shapes(seed)

    out_area=Area(seed)

    And now some background. Area(x) returns valid area of she list, which I've checked. In seed at the beginning there are some shapes which do not overlap (I've executed the or_shapes procedure). Oversize(x,k) oversizes all shapes in x by the factor k. And the problem is that the out_area<in_area (after_oversize>in_area), while it shouldn't be. In worst case the out_area should be equal to in_area. Maybe the dbLayerOr function has some limitations, or maybe I'm doing something else wrong. Any suggestions would be much appreciated.

    • Post Points: 20
  • Mon, Oct 19 2009 12:55 AM

    Re: Problem with dbLayerOr Reply

    I'm not aware of any problems with dbLayerOr() - I'd be surprised. Most likely is something wrong with your Area code - I'd have thought it would be fairly obvious by looking at the layout at each step.

    Perhaps you can contact me directly and then send me the code and data which shows the problem, and I'll try to take a quick look?

    Best Regards,

    Andrew.

    • Post Points: 20
  • Mon, Oct 19 2009 1:53 PM

    • ToMWUT
    • Top 150 Contributor
    • Joined on Mon, Apr 20 2009
    • Warsaw, Poland
    • Posts 48
    • Points 795
    Re: Problem with dbLayerOr Reply

    Thanks Andrew,

    I found the solution to my problem. While using leSizeShape procedure it turned up that, while oversizing it is possible that the procedure returns more than one shape. In my algorithm I was prepared for just one shape and other shapes weren't taken into account in my algorithm. That's the reason why the area was smaller. By the way I'm still quite surprised that while oversizing one shape it is possible for procedures to return shapes list (more then one shape in it). How is it possible?

    ToM

    • Post Points: 20
  • Mon, Oct 19 2009 2:02 PM

    Re: Problem with dbLayerOr Reply

    Hi ToM,

    If the resulting shape has too many vertices (more than 4000 if I remember rightly) then it will be split into multiple shapes. There's a maximum number of allowed vertices in a polygon in the database, so it has to do this.

    That's the most likely explanation. I'm assuming shapes when oversized collide with other oversized shapes, and that could result in a shape with lots of vertices?

    Regards,

    Andrew.

    • Post Points: 5
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Started by ToMWUT at 17 Oct 2009 06:01 AM. Topic has 3 replies.