Running examples in ‘xspliner-Ex.R’ failed
The error most likely occurred in:

> base::assign(".ptime", proc.time(), pos = "CheckExEnv")
> ### Name: xspline
> ### Title: Builds predictive model based GLM.
> ### Aliases: xspline model_surrogate_xspliner xspline.default
> ###   xspline.formula xspline.explainer
> 
> ### ** Examples
> 
> # preparing blackbox model
> library(randomForest)
randomForest 4.6-14
Type rfNews() to see new features/changes/bug fixes.
> rf_iris <- randomForest(
+   Petal.Width ~  Sepal.Length + Petal.Length + Species,
+   data = iris)
> 
> # formula based xspliner
> xs_iris <- xspline(
+   Petal.Width ~ xs(Sepal.Length) + xs(Petal.Length) + xf(Species),
+   model = rf_iris)
Cannot extract model family. Use gaussian.
Cannot extract model link. Use identity.
> summary(xs_iris)

Call:
glm(formula = Petal.Width ~ xs(Sepal.Length) + xs(Petal.Length) + 
    xf(Species), family = family, data = data)

Deviance Residuals: 
     Min        1Q    Median        3Q       Max  
-0.67743  -0.07560  -0.02699   0.09456   0.47393  

Coefficients:
                      Estimate Std. Error t value Pr(>|t|)    
(Intercept)            -1.3786     0.2877  -4.792 4.05e-06 ***
xs(Sepal.Length)        0.3828     0.3474   1.102    0.272    
xs(Petal.Length)        1.6979     0.3521   4.822 3.55e-06 ***
xf(Species)versicolor   0.0405     0.1833   0.221    0.825    
xf(Species)virginica    0.3711     0.2422   1.532    0.128    
---
Signif. codes:  0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

(Dispersion parameter for gaussian family taken to be 0.03092821)

    Null deviance: 86.5699  on 149  degrees of freedom
Residual deviance:  4.4846  on 145  degrees of freedom
AIC: -88.817

Number of Fisher Scoring iterations: 2

> plot(xs_iris, "Sepal.Length")
Error in grid.Call.graphics(C_setviewport, vp, TRUE) : 
  VECTOR_ELT() can only be applied to a 'list', not a 'double'
Calls: <Anonymous> ... push.vp.vpTree -> push.vp -> push.vp.viewport -> grid.Call.graphics
Execution halted