Input and Output

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Input and Output

Suppose we have some data in an ascii file of the form

etc, representing some P-wave velocity measurements, and a similar file with density measurements. We would like to be able to read into Lisp-Stat and do some calculations and make some plots.

> (def vp (read-data-file "pwavelog") )
> (def rho (read-data-file "densitylog"))
> (def imp (* rho vp))

This is pretty self-evident. And while we were at it, we computed the impedance with a simple vectorized multiplication of the velocity and density, stuffing the results into an array called imp.

Now we can look at, let's say, a scatter plot matrix of velocity, density, impedance against depth (the latter we'll make up with iseq)

> (scatterplot-matrix (list rho vp imp (iseq 1 (length imp))) 
        :variable-labels (list "Density" "Velocity" "Impedance" "Depth"))

which produces the results shown in Figure 1.4.

Figure 1.4: A scatter plot of the velocity and density logs along with impedance and depth.

Or we can make a spin plot of density, velocity and depth:

> (def depth (iseq 1 (length imp)))
> (spin-plot (list rho vp depth))

as shown in Figure 1.5.

Figure 1.5: A spinning plot of the velocity and density logs along with depth.

Tue Aug 29 09:10:30 MDT 1995