covariance values

[mnfienen]

in setup_pestpp_interface.ipynb the value of covariances for just ks must be smaller than 0.01. NaNing them out results in an empty figure in the block below.

cov = pf.build_prior()
x = cov.x.copy()
x[x<0.01] = np.NaN
plt.imshow(x)

[jtwhite79]

not surprised by that - we probably want to do a better job of showing how to set both bnds and ult bnds since that is big part of all this.