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Print Matrices or Matrix Operations Side by Side

Source: R/printMatEqn.R
printMatEqn.Rd

This function is designed to print a collection of matrices, vectors, character strings and matrix expressions side by side. A typical use is to illustrate matrix equations in a compact and comprehensible way.

Usage

printMatEqn(..., space = 1, tol = sqrt(.Machine$double.eps), fractions = FALSE)

Arguments

...

matrices and character operations to be passed and printed to the console. These can include named arguments, character string operation symbols (e.g., "+")

space

amount of blank spaces to place around operations such as "+", "-", "=", etc

tol

tolerance for rounding

fractions

logical; if TRUE, try to express non-integers as rational numbers, using the fractions function; if you require greater accuracy, you can set the cycles (default 10) and/or max.denominator (default 2000) arguments to fractions as a global option, e.g., options(fractions=list(cycles=100, max.denominator=10^4)).

Value

NULL; A formatted sequence of matrices and matrix operations is printed to the console

See also

showEqn

Author

Phil Chalmers

Examples


A <- matrix(c(2, 1, -1,
             -3, -1, 2,
             -2,  1, 2), 3, 3, byrow=TRUE)
x <- c(2, 3, -1)

# provide implicit or explicit labels
printMatEqn(AA = A, "*", xx = x, '=', b = A %*% x)
#>        AA     xx       b
#>   2  1 -1  *   2  =    8
#>  -3 -1  2      3     -11
#>  -2  1  2     -1      -3
printMatEqn(A, "*", x, '=', b = A %*% x)
#>         A      x       b
#>   2  1 -1  *   2  =    8
#>  -3 -1  2      3     -11
#>  -2  1  2     -1      -3
printMatEqn(A, "*", x, '=', A %*% x)
#>         A      x     A %*% x
#>   2  1 -1  *   2  =        8
#>  -3 -1  2      3         -11
#>  -2  1  2     -1          -3

# compare with showEqn
b <- c(4, 2, 1)
printMatEqn(A, x=paste0("x", 1:3),"=", b)
#>         A  x     b
#>   2  1 -1 x1  =  4
#>  -3 -1  2 x2     2
#>  -2  1  2 x3     1
showEqn(A, b)
#>  2*x1 + 1*x2 - 1*x3  =  4 
#> -3*x1 - 1*x2 + 2*x3  =  2 
#> -2*x1 + 1*x2 + 2*x3  =  1 

# decimal example
A <- matrix(c(0.5, 1, 3, 0.75, 2.8, 4), nrow = 2)
x <- c(0.5, 3.7, 2.3)
y <- c(0.7, -1.2)
b <- A %*% x - y

printMatEqn(A, "*", x, "-", y, "=", b)
#>               A       x        y          b
#>  0.50 3.00 2.80  *  0.5  -   0.7  =  17.090
#>  1.00 0.75 4.00     3.7     -1.2     13.675
#>                     2.3                    
printMatEqn(A, "*", x, "-", y, "=", b, fractions=TRUE)
#>             A         x        y            b
#>  1/2   3 14/5  *    1/2  -  7/10  =  1709/100
#>    1 3/4    4     37/10     -6/5       547/40
#>                   23/10