# ssq: Sum of the Squared Residuals In hydroGOF: Goodness-of-Fit Functions for Comparison of Simulated and Observed Hydrological Time Series

## Description

Sum of the Squared Residuals between `sim` and `obs`, with treatment of missing values. Its units are the squared measurement units of `sim` and `obs`.

## Usage

 ``` 1 2 3 4 5 6 7 8 9 10``` ```ssq(sim, obs, ...) ## Default S3 method: ssq(sim, obs, na.rm = TRUE, ...) ## S3 method for class 'data.frame' ssq(sim, obs, na.rm=TRUE, ...) ## S3 method for class 'matrix' ssq(sim, obs, na.rm=TRUE, ...) ```

## Arguments

 `sim` numeric, zoo, matrix or data.frame with simulated values `obs` numeric, zoo, matrix or data.frame with observed values `na.rm` a logical value indicating whether 'NA' should be stripped before the computation proceeds. When an 'NA' value is found at the i-th position in `obs` OR `sim`, the i-th value of `obs` AND `sim` are removed before the computation. `...` further arguments passed to or from other methods.

## Value

Sum of the squared residuals between `sim` and `obs`.

If `sim` and `obs` are matrixes, the returned value is a vector, with the SSR between each column of `sim` and `obs`.

## Note

`obs` and `sim` has to have the same length/dimension

The missing values in `obs` and `sim` are removed before the computation proceeds, and only those positions with non-missing values in `obs` and `sim` are considered in the computation

## Author(s)

Mauricio Zambrano Bigiarini <[email protected]>

## Examples

 ``` 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25``` ```obs <- 1:10 sim <- 1:10 ssq(sim, obs) obs <- 1:10 sim <- 2:11 ssq(sim, obs) ################## # Loading daily streamflows of the Ega River (Spain), from 1961 to 1970 data(EgaEnEstellaQts) obs <- EgaEnEstellaQts # Generating a simulated daily time series, initially equal to the observed series sim <- obs # Computing the 'rNSeff' for the "best" (unattainable) case ssq(sim=sim, obs=obs) # Randomly changing the first 2000 elements of 'sim', by using a normal distribution # with mean 10 and standard deviation equal to 1 (default of 'rnorm'). sim[1:2000] <- obs[1:2000] + rnorm(2000, mean=10) # Computing the new 'rNSeff' ssq(sim=sim, obs=obs) ```

hydroGOF documentation built on Aug. 8, 2017, 5:05 p.m.