Built-In Functions

In addition to simple arithmetic operations (+, -, *, /), Star-Hspice provides a number of built-in functions that you can use in expressions. The Star-Hspice built-in functions are listed in Star-Hspice Built-in Functions.

Table 7-2: Star-Hspice Built-in Functions
HSPICE Form	Function	Class	Description
sin(x)	sine	trig	Returns the sine of x (radians)
cos(x)	cosine	trig	Returns the cosine of x (radians)
tan(x)	tangent	trig	Returns the tangent of x (radians)
asin(x)	arc sine	trig	Returns the inverse sine of x (radians)
acos(x)	arc cosine	trig	Returns the inverse cosine of x (radians)
atan(x)	arc tangent	trig	Returns the inverse tangent of x (radians)
sinh(x)	hyperbolic sine	trig	Returns the hyperbolic sine of x (radians)
cosh(x)	hyperbolic cosine	trig	Returns the hyperbolic cosine of x (radians)
tanh(x)	hyperbolic tangent	trig	Returns the hyperbolic tangent of x (radians)
abs(x)	absolute value	math	Returns the absolute value of x: \|x\|
sqrt(x)	square root	math	Returns the square root of the absolute value of x: sqrt(-x) = -sqrt(\|x\|)
pow(x,y)	absolute power	math	Returns the value of x raised to the integer part of y: x(integer part of y)
pwr(x,y)	signed power	math	Returns the absolute value of x raised to the y power, with the sign of x: (sign of x)\|x\|y
log(x)	natural logarithm	math	Returns the natural logarithm of the absolute value of x, with the sign of x: (sign of x)log(\|x\|)
log10(x)	base 10 logarithm	math	Returns the base 10 logarithm of the absolute value of x, with the sign of x: (sign of x)log10(\|x\|)
exp(x)	exponential	math	Returns e raised to the power x: ex
db(x)	decibels	math	Returns the base 10 logarithm of the absolute value of x, multiplied by 20, with the sign of x: (sign of x)20log10(\|x\|)
int(x)	integer	math	Returns the integer portion of x. The fractional portion of the number is lost.
sgn(x)	return sign	math	Returns -1 if x is less than 0, 0 if x is equal to 0, and 1 if x is greater than 0
sign(x,y)	transfer sign	math	Returns the absolute value of x, with the sign of y: (sign of y)\|x\|
min(x,y)	smaller of two args	control	Returns the numeric minimum of x and y
max(x,y)	larger of two args	control	Returns the numeric maximum of x and y
lv(<Element>) or lx(<Element>)	element templates	various	Returns various element values during simulation. See "Element Template Output" in Chapter 7 for more information.
v(<Node>), i(<Element>)...	circuit output variables	various	Returns various circuit values during simulation. See DC and Transient Output Variables for more information.

Star-Hspice reserves the variable names listed in Star-Hspice Special Variables for use in elements such as E, G, R, C, and L. You cannot use them for any other purpose in your netlist (in .PARAM statements, for example) .

Table 7-3: Star-Hspice Special Variables
HSPICE Form	Function	Class	Description
time	current simulation time	control	Parameterizes the current simulation time during transient analysis.
temper	current circuit temperature	control	Parameterizes the current simulation temperature during transient/temperature analysis.
hertz	current simulation frequency	control	Parameterizes the frequency during AC analysis.

User-Defined Functions

An expression can contain parameters that have not yet been defined. A function must have at least one argument, and not more than two. Functions can be redefined.

Syntax

fname1 (arg1, arg2) = expr1 (fname2 (arg1, ...) = expr2) off

where:

fname	Specifies function name. This parameter must be distinct from array names and built-in functions. Subsequently defined functions must have all their embedded functions previously defined.
arg1, arg2	Specifies variables used in the expression.
off	Voids all user-defined functions.

Example

f(a,b) = POW(a,2)+a*b g(d) = SQRT(d) h(e) = e*f(1,2)-g(3)

Star-Hspice Manual - Release 2001.2 - June 2001