R/sumT.R
sumReciprocal.Rd
Reciprocal of the sum of the reciprocals of conductance Transition* objects
sumReciprocal(x1, x2)
x1 


x2 

TransitionLayer object containing conductance values.
To calculate the total resistance of two resistors that are serially
connected, we should add their resistance values. However, if we work
with conductance values, we need to take the reciprocal of the summed
reciprocals of the conductance values. This function does that when
adding two TransitionLayers with conductance values
(matrixValues(tr) == "conductance"
).
For a TransitionLayer with resistance values
(matrixValues(tr) == "resistance"
), the function will not take
reciprocals for that object, but will still take a reciprocal for the
final product (which will consequently have conductance values).
#Create a new raster and set all its values to unity. raster < raster(nrows=18, ncols=36) raster < setValues(raster,rep(1,ncell(raster))) #Create TransitionLayer objects tr1 < transition(raster,mean,4) tr2 < tr1 matrixValues(tr1) #Set one to resistance matrixValues(tr2) < "resistance" #Sum the two objects sumReciprocal(tr1,tr2)