editmatrix: Create an editmatrix

Description

An editmatrix is a numerical matrix and a set of comparison operators representing a linear system of (in)equations.

Usage

editmatrix(editrules, normalize = TRUE)
# S3 method for editmatrix
as.data.frame(x, ...)
# S3 method for editmatrix
as.character(x, ...)
# S3 method for editmatrix
as.expression(x, ...)
# S3 method for editmatrix
as.matrix(x, ...)
# S3 method for editmatrix
c(...)
# S3 method for editmatrix
str(object, ...)
# S3 method for editmatrix
summary(object, useBlocks = TRUE, ...)

Value

editmatrix : An object of class editmatrix

as.data.frame a 3-column data.frame with columns 'name' and 'edit'. If the input editmatrix has a description attribute a third column is returned.

as.matrix: Augmented matrix of editmatrix. (See also getAb).

Arguments

editrules: A character or expression vecotr with (in)equalities written in R syntax. Alternatively, a data.frame with a column named edits, see details.
normalize: logical specifying if all edits should be transformed (see description)
x: editmatrix object
...: Arguments to pass to or from other methods
object: an R object
useBlocks: logical Summarize each block?

Details

The function editmatrix generates an editmatrix from a character vector, an expression vector or a data.frame with at least the column edit. The function editfile reads edits from a free-form textfile, function as.editmatrix converts a matrix, a vector of constants and a vector of operators to an editmatrix

By default, the editmatrix is normalized, meaning that all comparison operators are converted to one of <, <=, or ==. Users may specify edits using any of the operators <, <=, ==, >=, > (see examples below). However it is highly recommended to let editmatrix parse them into normal form as all functions operating on editmatrices expect or convert it to normal form anyway.

Examples

Run this code

# Using a character vector to define contraints
E <- editmatrix(c("x+3*y==2*z", "x==z"))
print(E)

# Using a expression vector to define contraints
E <- editmatrix(expression(x+3*y==2*z, x==z))
print(E)

# an editmatrix also has a summary method:
summary(E)

# select rows from an editmatrix:
E <- editmatrix(c("x+3*y==2*z", "x >= z"))
E[getOps(E) == "=="]


#Using data.frame to define constraints
E.df <- data.frame(
    name =c("A","B","C"),
    edit = c("x == y",    
            "z + w == y + x",
            "z == y + 2*w"),
    description = c(
            "these variables should be equal","","")

)
print(E.df)

E <- editmatrix(E.df)
print(E)
# Using a character vector to define contraints
E <- editmatrix(c("x+3*y==2*z", "x==z"))
print(E)

# Using a expression vector to define contraints
E <- editmatrix(expression(x+3*y==2*z, x==z))
print(E)

# an editmatrix also has a summary method:
summary(E)

# select rows from an editmatrix:
E <- editmatrix(c("x+3*y==2*z", "x >= z"))
E[getOps(E) == "=="]


#Using data.frame to define constraints
E.df <- data.frame(
    name =c("A","B","C"),
    edit = c("x == y",    
            "z + w == y + x",
            "z == y + 2*w"),
    description = c(
            "these variables should be equal","","")

)
print(E.df)

E <- editmatrix(E.df)
print(E)

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