readme1

BSIM with Look-Up Table (LUT)
BSIM LUT speedup
G. Serdyuk <gena@analograils.com>
 
1. Intro
--------
Idea is straighforward - substitute part of calculations with Look-Up Table.

2. Installation
---------------
- put models-bsim.lut directory below gnucap
gnucap
    src
    ...
    models-bsim (optional)
    models-bsim.lut
    
- cd BSIM3v330.lut

- make

bsim330.lut.so  library will be created. Use it as usual (gnucap -a bsim330.lut.so .... 
or .attach bsim330.lut.so)

2.1.Developers version
---------------------
- put models-bsim.lut directory below gnucap
- cd BSIM3v330.lut
- make -f Makefile.work

this will clreate two libraries - bsim330.so and bsim330.lut.so
bsim330.so - usual bsim model, no changes
bsim330.lut.so - models which supports LUT

just attach them to gnucap as usual (-a or .attach)

3. Usage
--------

model supports 9 new parameters
vgsmin, vgsmax, vgsnum
vdsmin, vdsmax, vdsnum
vbsmin, vbsmax, vbsnum

that are correspondently minimum and maximum expected voltages 
and number of grid points between them.
defaults are: -5, +5 and 20.

Reasonable (from convergencve point of view) are 
vgsmin, vgsmax, vgsnum  =  -5 +5 50
vdsmin, vdsmax, vdsnum  =  -5 +5 50
vbsmin, vbsmax, vbsnum  =  -5 +5 10

If actual voltage will go out of vxxmin..vxxmax range, full BSIM 
calculation will be performed

Device support 1 new parameter:
lut_mode = 0 1 or 2

0 - full BSIM model
1 - BSIM model w/o change calculation
3 - LUT used
4 - LUT with precision monitoring (output is not elaborated)

4. ToDO
-------

1) clean up code and makefile
   + clean printf-s			done
   + use gnucap/spice-wrapper.cc	done
   - remove extra lines in main code	done
   + use standard Makefile		done
   
2) finish test cases
    - tran
	+ comprt
	TBD
    - dc
	TBD
    - time comparison
	+ speed  			done 
	(many subsequent calls of b3load)
	...
3) combine multiple LUTs for same devices - 
					TBD
4) write doc				done
5) optimize time			done (#define used)
6) check derivatives  			TBD