R Programming Language is frequently used for data visualization and analysis. But just like any program, R might have bugs. One frequent problem that users run across is the qr. default error. This mistake usually arises when working with linear algebraic procedures, especially those involving QR decomposition. We will examine the root causes of the qr. default problem and offer detailed fixes in this post.

Common Error for qr. default in R

1. Data must be numeric

This error occurs when attempting to use non-numeric data with functions that require numeric input.

# Error Example
data <- c("a", "b", "c")
qr.default(data)

Output :

Error in qr.default(data) : NA/NaN/Inf in foreign function call (arg 1)
In addition: Warning message: In storage.mode(x) <- "double" : NAs introduced by coercion

To solve this error ensure that the input data provided to the qr.default() function is numeric.

# Solution Example
data <- c(1, 2, 3)
qr.default(data)

Output :

$qr
           [,1]
[1,] -3.7416574
[2,]  0.5345225
[3,]  0.8017837

$rank
[1] 1

$qraux
[1] 1.267261

$pivot
[1] 1

attr(,"class")
[1] "qr"

2.Negative Number of Columns

This error occurs because specifying a negative number of columns (ncol) for a matrix is invalid. Matrices must have a non-negative number of columns, and providing a negative value violates this constraint.

# Error Example
matrix_F <- matrix(1:6, nrow = 2, ncol = -3)
result <- qr.default(matrix_F)

Output :

Error in matrix(1:6, nrow = 2, ncol = -3) : invalid 'ncol' value (< 0)

To fix this error ensure a non-negative number of columns for the matrix. Adjust the ncol parameter to have a valid positive value.

# Solution Example
positive_ncol <- 3  # Adjust this to a valid positive value
matrix_F <- matrix(1:6, nrow = 2, ncol = positive_ncol)
result <- qr.default(matrix_F)
result

Output :

$qr
           [,1]       [,2]      [,3]
[1,] -2.2360680 -4.9193496 -7.602631
[2,]  0.8944272 -0.8944272 -1.788854

$rank
[1] 2

$qraux
[1] 1.4472136 0.8944272 1.7888544

$pivot
[1] 1 2 3

attr(,"class")
[1] "qr"

3. Parentheses error

# Error Example
matrix <- matrix(1:9, nrow = 3)
qr.default(matrix))

Output :

Error: unexpected ')' in "qr.default(matrix))"

This error is due to an extra closing parenthesis. Remove the extra parenthesis from the code.

To avoid this error ensure there is only one closing parenthesis after the qr.default() function call.

# Solution example 
matrix <- matrix(1:9, nrow = 3)
qr.default(matrix)

Output :

$qr
           [,1]      [,2]          [,3]
[1,] -3.7416574 -8.552360 -1.336306e+01
[2,]  0.5345225  1.963961  3.927922e+00
[3,]  0.8017837  0.988693  1.776357e-15

$rank
[1] 2

$qraux
[1] 1.267261e+00 1.149954e+00 1.776357e-15

$pivot
[1] 1 2 3

attr(,"class")
[1] "qr"

4.Object Not Found Error

This error occur when you’re try to call the qr.default function with a data matrix object that doesn’t exist.

# Error Example 
data_matrix <- matrix(1:6, nrow = 2, ncol = 2)

# Attempt to call qr.default with a non-existent matrix
qr.default(nonexistent_matrix)

Output :

Error in as.matrix(x) : object 'nonexistent_matrix' not found

To avoid this error Ensure that the data matrix object is properly created and assigned before calling the qr.default function.

# Create a sample data matrix
data_matrix <- matrix(1:6, nrow = 2, ncol = 2)

# Attempt to call qr.default with a non-existent matrix
qr.default(data_matrix)

Output :

$qr
           [,1]       [,2]
[1,] -2.2360680 -4.9193496
[2,]  0.8944272 -0.8944272

$rank
[1] 2

$qraux
[1] 1.4472136 0.8944272

$pivot
[1] 1 2

attr(,"class")
[1] "qr"

Conclusion

To resolve the qr.default error in R, address syntax errors, give missing arguments, and ensure package compatibility. By following the diagnostic procedures indicated in this tutorial and implementing advanced prevention measures, users can effectively solve and avoid the occurrence of this mistake in their R code.