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deducorrect (version 1.3.7)

correctRounding: Correct records under linear restrictions for rounding errors

Description

This algorithm tries to detect and repair records that violate linear (in)equality constraints by correcting possible rounding errors as described by Scholtus(2008). Typically data is constrainted by $Rx=a$ and $Qx \ge b$.

Usage

correctRounding(E, dat, ...)
"correctRounding"(E, dat, ...)
"correctRounding"(E, dat, fixate = NULL, delta = 2, K = 10, round = TRUE, assumeUnimodularity = FALSE, ...)

Arguments

E
editmatrix or editset as generated by the editrules package.
dat
data.frame with the data to be corrected
...
arguments to be passed to other methods.
fixate
character with variable names that should not be changed.
delta
tolerance on checking for rounding error
K
number of trials per record. See details
round
should the solution be rounded, default TRUE
assumeUnimodularity
If FALSE, a test is performed before corrections are computed (expensive).

Value

A deducorrrect object.

Details

The algorithm first finds violated constraints $|r'_{i}x-a_i| > 0$ , and selects edits that may be due to a rounding error $0 < |r'_{i}x-a_i| \leq \delta$. The algorithm then makes a correction suggestion where the errors are attributed to randomly selected variables under the lineair equality constraints. It checks if the suggested correction does not violate the inequality matrix $Q$. If it does, it will try to generate a different solution up till K times.

References

Scholtus S (2008). Algorithms for correcting some obvious inconsistencies and rounding errors in business survey data. Technical Report 08015, Statistics Netherlands.

See Also

deducorrect-object status

Examples

Run this code

E <- editmatrix(expression( 
    x1 + x2 == x3,
    x2 == x4,
    x5 + x6  + x7 == x8,
    x3 + x8 == x9,
    x9 - x10 == x11
    )
)

dat <- data.frame( x1=12
                 , x2=4
                 , x3=15
                 , x4=4
                 , x5=3
                 , x6=1
                 , x7=8
                 , x8=11
                 , x9=27
                 , x10=41
                 , x11=-13
                 )

sol <- correctRounding(E, dat)


# example with editset
for ( d in dir("../pkg/R/",full.names=TRUE) ) dmp <- source(d)
E <- editmatrix(expression(
    x + y == z,
    x >= 0,
    y >= 0,
    z >= 0,
    if ( x > 0 ) y > 0
    ))
dat <- data.frame(
    x = 1,
    y = 0,
    z = 1)
# solutions causing new violations of conditional rules are rejected 
sol <- correctRounding(E,dat)

# An example with editset
E <- editset(expression(
    x + y == z,
    x >= 0,
    y > 0,
    y < 2,
    z > 1,
    z < 3,
    A %in% c('a','b'),
    B %in% c('c','d'),
    if ( A == 'a' ) B == 'b',
    if ( B == 'b' ) x < 1
))
dat <- data.frame(
    x = 0,
    y = 1,
    z = 2,
    A = 'a',
    B = 'b'
)

correctRounding(E,dat)    

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