Adjust metrics.scale.freeness to igraph changes

Since version 2.0.0 of package `igraph`, the function `igraph::power_law_fit`
(and its deprecated alias `igraph::fit.power.law`) does not automatically
compute the p-value any more, which is needed by `metrics.scale.freeness`.
In version 2.1.1 of package `igraph`, they have added a new parameter
`p.value` to provide the possibility to enable p-value computation
again. In addition, they have added a parameter `p.precision` which
defaults to a precision of 0.01.

To make `metrics.scale.freeness` work again with the most recent version
of package `igraph`, the deprecated function calls to
`igraph::fit.power.law` are replaced by `igraph::power_law_fit` and are
adjusted to use the new parameter `p.value` to automatically compute the
p-value again. However, we do not make use of `p.precision` and rely on
the default precision instead.

Signed-off-by: Thomas Bock <[email protected]>

util-networks-metrics.R

@@ -234,7 +234,7 @@ metrics.scale.freeness = function(network, minimum.number.vertices = 30) {
 
     ## Power-law fiting
     ## (by  Mitchell Joblin <[email protected]>, Siemens AG,  2012, 2013)
-    p.fit = igraph::power.law.fit(v.degree, implementation = "plfit")
+    p.fit = igraph::fit_power_law(v.degree, implementation = "plfit", p.value = TRUE)
     param.names = c("alpha", "xmin", "KS.p")
     res = list()
     res[param.names] = p.fit[param.names]
@@ -250,7 +250,7 @@ metrics.scale.freeness = function(network, minimum.number.vertices = 30) {
        & non.zero.degree.v.count >= minimum.number.vertices) {
         ## vertex degree is sorted above
         x.min = v.degree[[minimum.number.vertices]]
-        p.fit = power.law.fit(v.degree, implementation = "plfit", xmin = x.min)
+        p.fit = igraph::fit_power_law(v.degree, implementation = "plfit", xmin = x.min, p.value = TRUE)
         res[param.names] = p.fit[param.names]
 
         ## Check percent of vertices under power-law