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String Parameters

method
This string can be set to either of the keywords ``trap'', which is the default and sets trapezoidal integration, or ``gear'', for Gear integration. The maxord variable sets the maximum order of the integration.

Default Values Set From  
trap trap, gear Simulation Options/Timestep  

optmerge
This variable is used to specify the rule for dealing with options and variables that are set in the shell and also in the circuit (given in .options lines). The description of option merging in 2.4.4.1 explains the use of this variable.

Default Values Set From  
global global, local, noshell Simulation Options/Parser  

parhier
By default, parameters from .param lines, subcircuit instantiation lines, and subcircuit definition lines have top-down precedence, meaning that when resolving parameter name clashes, the definition at the highest level in the subcircuit hierarchy takes precedence. Thus, by default, parameters defined in .param lines outside of any subcircuit will override parameters of the same name anywhere in the hierarchy.

The parhier option variable can be set to one of the keywords ``global'' or ``local''. The ``global'' setting retains default behavior. The ``local'' setting reverses the precedence to bottom-up. In this case, parameter definitions at the lowest level within subcircuits will have precedence.

The parameter scoping rules are identical to HSPICE in release 3.2.15 and later. Earlier releases had different scoping rules, with the default being closer but not identical to the ``local'' rule.

Default Values Set From  
global global, local Simulation Options/Parser  

steptype
This string can be set to one of four keywords which determine the data output mode in transient analysis. It can be set to ``interpolate'', which is the default, ``hitusertp'', ``nousertp'', or ``fixedstep''. The integers 0, 1, 2, 3 are effectively synonyms for these keywords.

If not set, or set to ``interpolate'', output points are interpolated from internal time points to the user time increments, with degree 1 (the default) to 3, set by the interplev variable.

If set to ``hitusertp'', then during transient analysis the time step will be cut so as to land on the user time points. This requires more simulation time, but provides the greatest accuracy.

Setting to ``nousertp'' will cause internal timepoint data to be saved, either in internal data structures in interactive mode or in the rawfile in batch mode. The amount of data can grow quite large.

If set to ``fixedstep'', operation is similar to ``hitusertp'', however the internal time step is constrained to this value exactly. No smaller time step is taken, if convergence fails then the run terminates. The time delta is that given for the transient analysis. This mode is only useful for debugging as truncation error is ignored. As a side-effect the integration method will be rectangular.

Default Values Set From  
interpolate interpolate, hitusertp, nousertp, fixedstep Simulation Options/Timestep  


next up previous contents index
Next: Syntax Control Variables Up: Simulation Option Variables Previous: Boolean Parameters   Contents   Index
Stephen R. Whiteley 2017-02-22