# 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.

## Dot-test¶

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

## Describe¶

 describe(Op) Describe a PyLops operator

## Estimators¶

 trace_hutchinson(Op[, neval, batch_size, …]) Trace of linear operator using the Hutchinson method. trace_hutchpp(Op[, neval, sampler, backend]) Trace of linear operator using the Hutch++ method. trace_nahutchpp(Op[, neval, sampler, c1, …]) Trace of linear operator using the NA-Hutch++ method.

## Scalability test¶

 scalability_test(Op, x[, workers, forward]) Scalability test.

## 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
 marchenko.directwave(wav, trav, nt, dt[, …]) Analytical direct wave in acoustic media

## Signal-processing¶

 signalprocessing.convmtx(h, n) Convolution matrix signalprocessing.nonstationary_convmtx(H, n) Convolution matrix from a bank of filters signalprocessing.slope_estimate(d[, dz, dx, …]) Local slope estimation

## 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

## Geophysical 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. avo.ps(theta, vsvp[, n]) PS reflection coefficient