# scidart library Null safety

## Functions

arrayBesselI0()
Return modified Bessel function of order 0 for each element of Array. [...]
besselI0()
Return modified Bessel function of order 0 for a number. [...]
blackman(int M, {bool sym = true})
Return a Blackman window. The Blackman window is a taper formed by using the first three terms of a summation of cosines. It was designed to have close to the minimal leakage possible. It is close to optimal, only slightly worse than a Kaiser window. [...]
blackmanharris(int M, {bool sym = true})
Return a minimum 4-term Blackman-Harris window. [...]
convolution(Array input, Array kernel, {dynamic fast = false})
Compute the 1D convolution of 2 signals [...]
convolutionCircularComplex(ArrayComplex input, ArrayComplex kernel, {dynamic keepLength = false})
Computes the circular convolution of the given complex vectors. Each vector's length must be the same. [...]
convolutionComplex(ArrayComplex input, ArrayComplex kernel)
Compute the 1D convolution of 2 signals and return a ComplexArray [...]
correlate(Array input, Array kernel, {dynamic fast = false})
Compute the 1D cross-correlation of 2 signals [...]
correlateComplex(ArrayComplex input, ArrayComplex kernel)
Compute the 1D cross-correlation of 2 complex signals [...]
dbfft(Array x, double fs, { window, ref}) List
Calculate spectrum in dB scale [...]
fft({int? n, bool normalization = false, bool forceDft = false})
Compute the one-dimensional discrete Fourier Transform. Uses recursive Cooley–Tukey algorithm if N is power of 2 otherwise uses Discrete Fourier Transform algorithm. [...]
fftFreq(int n, {double d = 1.0, bool realFrequenciesOnly = false})
Return the Discrete Fourier Transform sample frequencies. The returned float array `f` contains the frequency bin centers in cycles per unit of the sample spacing (with zero at the start). For instance, if the sample spacing is in seconds, then the frequency unit is cycles/second. Given a window length `n` and a sample spacing `d`:: f = `0, 1, ..., n/2-1, -n/2, ..., -1` / (dn) if n is even f = `0, 1, ..., (n-1)/2, -(n-1)/2, ..., -1` / (dn) if n is odd [...]
findPeaks(Array a, { threshold}) List
Find the peak of Array [...]
firwin(int numtaps, Array cutoff, { width, dynamic window = 'hamming', dynamic pass_zero = true, bool scale = true, nyq, fs}) → dynamic
FIR filter design using the window method. This function computes the coefficients of a finite impulse response filter. The filter will have linear phase; it will be Type I if `numtaps` is odd and Type II if `numtaps` is even. Type II filters always have zero response at the Nyquist frequency, so a ValueError exception is raised if firwin is called with `numtaps` even and having a passband whose right end is at the Nyquist frequency. [...]
flattop(int M, {bool sym = true})
Return a flat top window. [...]
generalCosine(int M, Array a, {bool sym = true})
Generic weighted sum of cosine terms window [...]
generalHamming(int M, double alpha, {bool sym = true})
Return a generalized Hamming window. The generalized Hamming window is constructed by multiplying a rectangular window by one period of a cosine function `1`_. [...]
getWindow(dynamic window, int Nx, {bool fftbins = true})
Return a window. [...]
hamming(int M, {bool sym = true})
Return a Hamming window. The Hamming window is a taper formed by using a raised cosine with non-zero endpoints, optimized to minimize the nearest side lobe. [...]
hann(int M, {bool sym = true})
Return a Hann window. The Hann window is a taper formed by using a raised cosine or sine-squared with ends that touch zero. [...]
ifft()
Compute the one-dimensional inverse discrete Fourier Transform. [...]
kaiser(int M, double beta, {bool sym = true})
Return a Kaiser window. The Kaiser window is a taper formed by using a Bessel function. [...]
kaiserAtten(int numtaps, double width)
Compute the attenuation of a Kaiser FIR filter. Given the number of taps `N` and the transition width `width`, compute the attenuation `a` in dB, given by Kaiser's formula: a = 2.285 * (N - 1) * pi * width + 7.95 [...]
kaiserBeta()
Compute the Kaiser parameter `beta`, given the attenuation `a`. [...]
lfilter(Array b, Array a, )
Filter data along one-dimension with an IIR or FIR filter. The filter is a direct form II transposed implementation of the standard difference equation. [...]
nuttall(int M, {bool sym = true})
Return a minimum 4-term Blackman-Harris window according to Nuttall. This variation is called "Nuttall4c" by Heinzel. `1`_ [...]
rfft(Array x, {dynamic n})
Compute the one-dimensional discrete Fourier Transform for a Real input. [...]
rifft()
Compute the one-dimensional inverse discrete Fourier Transform and return a Real output. [...]