NMODL’s built-in functions

These functions, which are provided by the C language math library, can be called from within NMODL code. With the exception of abs(), all expect double-precision floating point arguments and return double-precision floating point values.

acos(x) - compute the arc cosine: Returns the arc cosine of its argument (arccosx). The argument must be in the range -1.0 to 1.0.
asin(x) - compute the arc sine: Returns the arc sine of its argument (arcsinx). The argument must be in the range -1.0 to 1.0.
atan(x) - compute the arc tangent: Returns the arc tangent of its argument (arctanx).
atan2(y,x) - compute the arc tangent of y/x: Returns the arc tangent of the ratio y/x (arctany/x).
ceil(x) - round upwards: Returns the smallest integral value greater than or equal to its argument (x).
cos(x) - compute the cosine: Returns the cosine of its argument (cosx). The angle is expressed in radians.
cosh(x) - compute the hyperbolic cosine: Returns the hyperbolic cosine for a real argument (coshx).
exp(x) - compute the exponential function: Returns the value of e raised to the argument power (ex).
fabs(x) - compute the absolute value of a floating point number: Returns the absolute value of its argument (|x|).
floor(x) - round downwards: Returns the largest integral value less than or equal to its argument (x).
fmod(x,y) - compute x modulo y: Returns the value of x modulo y (x y), the remainder resulting from x/y.
log(x) - compute the natural logarithm: Returns the natural logarithm of its argument (lnx).
log10(x) - compute the base 10 logarithm: Returns the base 10 logarithm of its argument (log10 x).
pow(x,y) - compute x raised to the y power: Returns the value of x raised to the power of y (x ^y).
sin(x) - compute the sine: Returns the sine of its argument (sinx). The angle is expressed in radians.
sinh(x) - compute the hyperbolic sine: Returns the hyperbolic sine for a real argument (sinhx).
sqrt(x) - compute the square root: Returns the positive square root of its argument (x).
tan(x) - compute the tangent: Returns the tangent of its argument (tanx). The angle is expressed in radians.
tanh(x) - compute the hyperbolic tangent: Returns the hyperbolic tangent for a real argument (tanhx).