Can anyone clear my synthsis doubt?

wire load model top segmented

I am confused with set_wire_load_model
a>top
b>enclosed
c>segmented.
Can anyone explain these in detail?
And also what is set_wire_lode_mode ? how both are diffrent?

top
Defines that all nets in the hierarchy will inherit the same wire load model as the top level block. Use it if when the plan is to flatten the design later for layout.

enclosed
Specifies all the nets (of the sub-blocks) inherit the wire load model of the block that completely encloses the sub-blocks. For example, if blocks X and Y are enclosed within block Z, then the blocks X and Y will inherit the wire load models defined for block Z.

segmented
Used when wires are crossing hierarchical boundaries. From the previous example, the sub-blocks X and Y will inherit the wire load models specific to them, while nets between sub-blocks X and Y(which are contained within Z) will inherit wire-load model specified for block Z
Not used often, as the wire load models are specific to the net segments

wire load mode :
1) conservative
2) aggressive

aggressive mode : the tool select the WC values as the delay for the nets !

conservative : the tool select a better value ( other than WC .... it wil be available in the .lib) as the delay for the nets !

wire_load_model : as explained above !!

more info on the same can be found in the DC/PT manuals !!!

DC uses wire load models to estimate RC delay before layout.

These wire load models are created by ASIC vendor and are extracted from the technology library.

If no wire load model is specified DC selects automatically.

Firstly use "auto_wire_load_selection = false" command to disable automation selection.

There are different modes using which wire selection model can be applied for nets.
They are

TOP: Ignores lower level wireloads (apllies wireloads only to top level nets and pins)

ENCLOSED: The tool uses best fitting solution needed for your design. Tool decides on which wire load model to be applied where.

SEGMENTED: Uses different wire loads available from the technology library.

NOTE: By default the mode used is "TOP" i.e wire load models are applied only to top level nets of the design .