# PyLops Utilities¶

Alongside with its Linear Operators and Solvers, PyLops contains also a number of auxiliary routines performing universal tasks that are used by several operators or simply within one or more Tutorials for the preparation of input data and subsequent visualization of results.

## Shared¶

### Dot-test¶

 dottest(Op, nr, nc[, tol, complexflag, …]) Dot test.

## Others¶

### Synthetics¶

 seismicevents.makeaxis(par) Create axes t, x, and y axes seismicevents.linear2d(x, t, v, t0, theta, …) Linear 2D events seismicevents.parabolic2d(x, t, t0, px, pxx, …) Parabolic 2D events seismicevents.hyperbolic2d(x, t, t0, vrms, …) Hyperbolic 2D events seismicevents.linear3d(x, y, t, v, t0, …) Linear 3D events seismicevents.hyperbolic3d(x, y, t, t0, …) Hyperbolic 3D events

### Signal-processing¶

 signalprocessing.convmtx(h, n) Convolution matrix

### Tapers¶

 tapers.taper2d(nt, nmask, ntap[, tapertype]) 2D taper tapers.taper3d(nt, nmask, ntap[, tapertype]) 3D taper

### Wavelets¶

 wavelets.ricker(t[, f0]) Ricker wavelet wavelets.gaussian(t[, std]) Gaussian wavelet

### Geophysicical Reservoir characterization¶

 avo.zoeppritz_scattering(vp1, vs1, rho1, …) Zoeppritz solution. avo.zoeppritz_element(vp1, vs1, rho1, vp0, …) Single element of Zoeppritz solution. avo.zoeppritz_pp(vp1, vs1, rho1, vp0, vs0, …) PP reflection coefficient from the Zoeppritz scattering matrix. avo.approx_zoeppritz_pp(vp1, vs1, rho1, vp0, …) PP reflection coefficient from the approximate Zoeppritz equation. avo.akirichards(theta, vsvp[, n]) Three terms Aki-Richards approximation. avo.fatti(theta, vsvp[, n]) Three terms Fatti approximation.