Set#

Adding Set Records#

Three possibilities exist to assign symbol records to a set: We show a few examples of ways to create differently structured sets.

Example #1 - Create a 1D set from a vector#

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

# NOTE: the above syntax is equivalent to -
# i = Set$new(m, "i")
# i$setRecords(c("seattle", "san-diego"))

# NOTE: the above syntax is also equivalent to -
# m$addSet("i", records= c("seattle", "san-diego"))

# NOTE: the above syntax is also equivalent to -
# i = m$addSet("i")
# i$setRecords(c("seattle", "san-diego"))

# NOTE: the above syntax is also equivalent to -
# m$addSet("i")
# m["i"]$setRecords(c("seattle", "san-diego"))

> i$records
        uni
1   seattle
2 san-diego

Example #2 - Create a 2D set from a list#

library(gamstransfer)
m <- Container$new()
k <- Set$new(m, "k", c("*", "*"), records = list("seattle", "san-diego"))

# NOTE: the above syntax is equivalent to -
# k = Set$new(m, "k", c("*", "*"))
# k$setRecords(list("seattle", "san-diego"))

# NOTE: the above syntax is also equivalent to -
# m$addSet("k", c("*","*"), records=list("seattle", "san-diego"))

# NOTE: the above syntax is also equivalent to -
# k = m$addSet("k", c("*","*"))
# k$setRecords(list("seattle", "san-diego"))

# NOTE: the above syntax is also equivalent to -
# m$addSet("k", c("*", "*"))
# m["k"]$setRecords(list("seattle", "san-diego"))

> k$records
    uni_1     uni_2
1 seattle san-diego

Example #3 - Create a 1D set from a data frame slice#

library(gamstransfer)
m <- Container$new()

dist <- data.frame(
from = c(
    "seattle", "seattle", "seattle",
    "san-diego", "san-diego", "san-diego"
),
to = c(
    "new-york", "chicago", "topeka",
    "new-york", "chicago", "topeka"
),
thousand_miles = c(2.5, 1.7, 1.8, 2.5, 1.8, 1.4)
)

l <- Set$new(m, "l", records = unique(dist[["from"]]))

# NOTE: the above syntax is equivalent to -
# l = Set$new(m, "l")
# l$setRecords(unique(dist[["from"]]))

# NOTE: the above syntax is also equivalent to -
# m$addSet("l", records=unique(dist[["from"]]))

# NOTE: the above syntax is also equivalent to -
# l = m$addSet("l")
# l$setRecords(unique(dist[["from"]]))

# NOTE: the above syntax is also equivalent to -
# m$addSet("l")
# m["l"]$setRecords(unique(dist[["from"]]))

> l$records
    uni
1   seattle
2 san-diego

Set element text is very handy when labeling specific set elements within a set. A user can add a set element text directly with a set element. Note that it is not required to label all set elements, as can be seen in the following example.

Example #4 - Add set element text#

library(gamstransfer)
m <- Container$new()
i <- Set$new(m, "i",
records <- data.frame(
    city = c("seattle", "san-diego", "washington_dc"),
    text = c("home of sub pop records", "", "former gams hq")
)
)

# NOTE: the above syntax is equivalent to -
#
# i = Set$new(m, "i")
# i_recs = data.frame(city=c("seattle", "san-diego", "washington_dc"),
# text=c("home of sub pop records", "", "former gams hq"))
#
# i$setRecords(i_recs)

# NOTE: the above syntax is also equivalent to -
# m$addSet("i", records=i_recs)

# NOTE: the above syntax is also equivalent to -
# i = m$addSet("i")
# i$setRecords(i_recs)

# NOTE: the above syntax is also equivalent to -
# m$addSet("i")
# m["i"]$setRecords(i_recs)

> i$records
        city            element_text
1       seattle home of sub pop records
2     san-diego
3 washington_dc          former gams hq

The primary advantage of the setRecords method is that GAMS Transfer R will convert many different (and convenient) data types into the standard data format (a data frame). Users that require higher performance will want to directly pass the Container a reference to a valid data frame, thereby skipping some of these computational steps. This places more burden on the user to pass the data in a valid standard form, but it speeds the records setting process. In this section, we walk the user through an example of how to set records directly.

Example #5 - Directly set records (1D set)#

library(gamstransfer)
m <- Container$new()
i <- Set$new(m, "i", description = "supply")

# create a standard format data frame
df_i <- data.frame(
uni_1 <- c("seattle", "san-diego"),
element_text = c("", "")
)

# need to create categorical column type, referencing elements already in df_i
df_i$uni_1 <- factor(df_i$uni_1, ordered = TRUE)

# set the records directly
i$records <- df_i

> i$isValid()
[1] TRUE

Stepping through this example we take the following steps:

  1. Create an empty Container

  2. Create a GAMS set i in the Container, but do not set the records

  3. Create a data frame (manually, in this example) taking care to follow the standard format

  4. The data frame has the right shape and column labels so we can proceed to set the records.

  5. We need to cast the uni_1 column as a factor, so we create a custom ordered category type using factor

  6. Finally, we set the records directly by passing a reference to df_i into the symbol records attribute. The setter function of records checks that a data frame is being set, but does not check validity. Thus, as a final step, we call the $isValid() method to verify that the symbol is valid.

Note

Users can debug their data frames by running <symbol_name>$isValid(verbose=TRUE) to get feedback about their data.

Example #6 - Directly set records (1D subset)#

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

# create a standard format data frame
df_j <- data.frame(i_1 = c("seattle"), "element_text" = c(""))

# create the categorical column type
df_j$i_1 <- factor(df_j$i_1, levels = i$records[, 1], ordered = TRUE)

# set the records
j$records <- df_j

> j$isValid()
[1] TRUE

This example is more subtle in that we want to create a set j that is a subset of i. We create the set i using the setRecords method but then set the records directly for j. There are two important details to note: 1) the column labels in df_j now reflect the standard format for a symbol with a domain set (as opposed to the universe) and 2) we create the factors by referencing the parent set (i) for the levels (instead of referencing itself).

Note

One can also use the generateRecords() method to automatically populate randomly generated symbol records in the standard format.

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