nauc {drda} | R Documentation |
Evaluate the normalized area under the curve (NAUC).
nauc(object, xlim = c(-10, 10), ylim = c(0, 1))
object |
fit object as returned by |
xlim |
numeric vector of length 2 with the lower and upped bound of the
integration interval. Default is |
ylim |
numeric vector of length 2 with the lower and upped bound of the
allowed function values. Default is |
The area under the curve (AUC) is simply the integral of the chosen model
y(x; theta)
with respect to x
.
In real applications the response variable is usually contained within a known interval. For example, if our response represents relative viability against a control compound, the curve is then expected to be between 0 and 1.
To make the AUC value comparable between different compounds and/or studies,
this function set a hard constraint on both the x
variable and the function
y
. The intervals can always be changed if needed.
The function f(x; theta)
that is integrated here is defined as
f(x; theta) = ylim[1], if y(x; theta) < ylim[1]
f(x; theta) = y(x; theta), if ylim[1] <= y(x; theta) <= ylim[2]
f(x; theta) = ylim[2], if y(x; theta) > ylim[2]
Finally, the AUC is normalized by its maximum possible value, that is the
area of the rectangle with width xlim[2] - xlim[1]
and height
ylim[2] - ylim[1]
.
Numeric value representing the normalized area under the curve.