Built-in Functions

Documentation

Reference

Built-in Functions

The listing below gives an overview of the built-in functions. The up-to-date list is always available from within Frida by typing hf at the main prompt.

Elementary functions

Function	Description
`ln(x)`	Natural logarithm; NaN if x ≤ 0
`lg(x)`	Decadic logarithm; NaN if x ≤ 0
`sqrt(x)`	Square root; NaN if x < 0
`abs(x)`	Absolute value
`sign(x)`	Sign: −1, 0, or 1
`exp(x)`	Exponential

Safe variants

These return 0 instead of NaN for out-of-domain arguments, which is useful when a few data points lie outside the valid range but you do not want the whole expression to evaluate to NaN:

Function	Description
`ln0(x)`	Natural logarithm; 0 if x ≤ 0
`lg0(x)`	Decadic logarithm; 0 if x ≤ 0
`sqrt0(x)`	Square root; 0 if x < 0

Trigonometric functions

Function	Description
`sin(x)`	Sine (x in radians)
`cos(x)`	Cosine (x in radians)
`tan(x)`	Tangent (x in radians)
`cot(x)`	Cotangent (x in radians)
`sind(x)`	Sine (x in degrees)
`cosd(x)`	Cosine (x in degrees)
`tand(x)`	Tangent (x in degrees)
`cotd(x)`	Cotangent (x in degrees)
`asin(x)`	Arc sine (result in radians; NaN if \|x\| > 1)
`acos(x)`	Arc cosine (result in radians; NaN if \|x\| > 1)
`atan(x)`	Arc tangent (result in radians)
`acot(x)`	Arc cotangent (result in radians)
`asind(x)`	Arc sine (result in degrees; NaN if \|x\| > 1)
`acosd(x)`	Arc cosine (result in degrees; NaN if \|x\| > 1)
`atand(x)`	Arc tangent (result in degrees)
`acotd(x)`	Arc cotangent (result in degrees)
`sinh(x)`	Hyperbolic sine
`cosh(x)`	Hyperbolic cosine
`tanh(x)`	Hyperbolic tangent
`coth(x)`	Hyperbolic cotangent
`sinc(x)`	Cardinal sine: sin(x)/x

Special functions

Function	Description
`gamma(x)`	Gamma function (= factorial of x−1)
`lgamma(x)`	Natural logarithm of the gamma function
`fac(x)`	Factorial of nearest integer of x
`cata(x)`	Catalan number of nearest integer of x
`erf(x)`	Error function
`erfc(x)`	Complementary error function
`erfi(x)`	Imaginary error function
`erfcx(x)`	Scaled complementary error function: exp(x²)·erfc(x)
`dawson(x)`	Dawson function: exp(−x²)·∫₀ˣ exp(t²) dt
`j0(x)`	Spherical Bessel function j₀
`j1(x)`	Spherical Bessel function j₁
`isnan(x)`	1 if x is NaN, 0 otherwise
`ceil(x)`	Smallest integer ≥ x
`floor(x)`	Largest integer ≤ x
`nint(x)`	Nearest integer

Two-argument functions

Function	Description
`min2(x,y)`	Smaller of x and y
`max2(x,y)`	Larger of x and y
`ran(x,y)`	Uniform random number in [x, y]
`hypot(x,y)`	√(x²+y²)
`atan2(x,y)`	Polar angle of point (x, y) in radians
`atan2d(x,y)`	Polar angle of point (x, y) in degrees
`gauss(x,s)`	Normalised Gaussian: exp(−x²/2s²) / (√(2π) s)
`gnn(x,s)`	Unnormalised Gaussian: exp(−x²/2s²)
`cauchy(x,w)`	Cauchy–Lorentz: w / (π(x²+w²))
`diehl(η)`	Normalised Gauss⊛Cauchy convolution (pseudo-Voigt); η = Cauchy/Gauss width
`lndiehl(η)`	Natural log of `diehl(η)`
`re_wofz(x,y)`	Real part of the Faddeeva function w(x+iy)
`im_wofz(x,y)`	Imaginary part of the Faddeeva function
`abs_wofz(x,y)`	Absolute value of the Faddeeva function
`arg_wofz(x,y)`	Phase of the Faddeeva function

Three-argument functions

Voigt profile

Function	Description
`voigt(x,σ,γ)`	Voigt profile: convolution of Gaussian(σ) and Lorentzian(γ)
`voigt_hwhm(σ,γ)`	Half-width at half-maximum of the Voigt profile

KWW (stretched exponential) transforms

The KWW functions compute Fourier transforms of the stretched exponential exp(−(t/τ)^β). See http://joachimwuttke.de/kww/ for details.

Function	Description
`kwwc(ω,τ,β)`	Cosine transform: ∫₀^∞ cos(ωt) exp(−(t/τ)^β) dt
`kwws(ω,τ,β)`	Sine transform
`kwwp(ω,τ,β)`	Primitive of the cosine transform
`kwwmc(ω,⟨τ⟩,β)`	Cosine transform averaged over a τ distribution
`kwwms(ω,⟨τ⟩,β)`	Sine transform averaged over a τ distribution
`kwwmp(ω,⟨τ⟩,β)`	Primitive averaged over a τ distribution

Havriliak–Negami

Function	Description
`rehavneg(x,y,z)`	Real part of the Havriliak–Negami function
`imhavneg(x,y,z)`	Imaginary part of the Havriliak–Negami function

Other physics functions

Function	Description
`cauchy2(x,y,z)`	Two-parameter Cauchy function
`debye1(x)`	Debye function D₁(x)
`debye3(x)`	Debye function D₃(x)
`debyeu2(x)`	Debye mean-squared-displacement temperature dependence
`debyeui(x)`	Debye internal energy
`debyecv(x)`	Debye heat capacity
`zorn(I,⟨I⟩,s)`	Multiple-scattering corrected elastic intensity (Zorn)
`zorn2(q,⟨u²⟩,s)`	Gaussian elastic intensity corrected for multiple scattering (Si111)
`heat_sphere(t,r)`	Temperature evolution in a sphere

Calculator examples

. ln(0)                         # NaN
. ln0(0)                        # 0
. sqrt(-1)                      # NaN
. sqrt0(-1)                     # 0
. sin(pi/4)^2 + cos(pi/4)^2    # 1
. gauss(0, 1)                   # 0.3989
. kwwc(0, 1, 0.5)              # KWW at ω=0, τ=1, β=0.5
. isnan(ln(-1))                 # 1