Validating Data#

GAMS Transfer R requires that the records for all symbols exist in a (standard format) in order for them to be understood by the Container. It is possible that the data could end up in a state that is inconsistent with the standard format (especially if setting symbol attributes directly). GAMS Transfer R includes the $isValid() method in order to determine if a symbol is valid. This method returns a logical. This method does not guarantee that a symbol will be successfully written to GDX. Other data errors (duplicate records, long UEL names, or domain violations) could exist that are not tested in $isValid(). For example, we create two valid sets and then check them with $isValid() to be sure.

It is possible to run $isValid() on both the Container as well as the symbol object. The Container method $isValid() will also return FALSE if there are any invalid symbols in the Container object. In addition, the Container$isValid() method also detects broken Container references in symbols and inconsistent symbol naming between the Container$data field and the symbol objects.

Example (valid data)#

library(gamstransfer)
m <- Container$new()
i <- Set$new(m, "i", records = c("seattle", "san-diego", "washington_dc"))
j <- Set$new(m, "j", i, records = c("san-diego", "washington_dc"))

> i$isValid()
[1] TRUE

> j$isValid()
[1] TRUE

> m$isValid()
[1] TRUE

Now we create some data that is invalid due to incorrect column names in the records for set j.

library(gamstransfer)
m <- Container$new()
i <- Set$new(m, "i", records = c("seattle", "san-diego", "washington_dc"))
j <- Set$new(m, "j", i)

j$records <- data.frame(cities = c("grayslake", "washington_dc"))

> i$isValid()
[1] TRUE

> j$isValid()
[1] FALSE

> m$isValid()
[1] FALSE

In this example, we use records field of the symbol j to set the records. As mentioned in setting the records, when setting records directly, users must adhere to standard formats. In this example, symbol j does not have the correct number of columns. Moreover, the column headings do not follow the convention (should be “i_1”). The user can get more detailed error reporting if the verbose argument is set to TRUE. For example:

> j$isValid(verbose=TRUE)
Symbol 'records' does not have the correct number of columns (<symbol dimension> + 1)
[1] FALSE

The $isValid() method checks: - If the symbol belongs to a Container - If all domain set symbols exist in the Container - If all domain set symbols objects are valid - If all domain sets are one dimensional - If records are a data frame (or NULL) - If the records domainLabels are unique - The shape of the records is congruent with the dimensionality of the symbol - That all data columns are type numeric - To make sure that all domain categories are type string

Note

Calling $isValid() too often may have a significant impact on the performance.

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