Lewkrr - 6 months ago 44

R Question

I am representing the following matrix:

`6 5 0`

0 5 4

0 0 4

as a data.frame. The data.frame in R has three columns. The COO format is as follows:

`i j Xij`

1 1 6

1 2 5

2 2 6

2 3 5

3 3 6

Note that there is no row

`[1 3 0]`

`matrix.coo`

`dgCMatrix`

`Matrix`

I do NOT want to convert it to a regular matrix first, as the dataset I am working with is very large, and writing a loop to convert it to a standard R matrix would take too long.

Answer

Looking at `?Matrix::sparseMatrix`

we can use the already-coded function as follows:

```
myMatrix <- Matrix::sparseMatrix(i = coo$i, j = coo$j, x = coo$Xij, dims = c(42, 42))
```

Source (Stackoverflow)