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 class 'editmatrix':
as.data.frame (x, ...)

  ## S3 method for class 'editmatrix':
as.character (x, ...)

  ## S3 method for class 'editmatrix':
as.expression (x, ...)

  ## S3 method for class 'editmatrix':
as.matrix (x, ...)

  ## S3 method for class 'editmatrix':
c (...)

  ## S3 method for class 'editmatrix':
str (object, ...)

  ## S3 method for class 'editmatrix':
summary (object, useBlocks = TRUE,
    ...)

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)

editmatrix object

object

an R object

useBlocks

logical Summarize each block?

...

Arguments to pass to or from other methods

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).

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 <,

<=< code="">, 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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