Documentation about calculations and arithmetics

nalgebra
1

Hey guys, maybe I’m just blind, but I haven’t found an overview of all the kinds of arithmetics and how to express them with nalgebra, apart from the obvious ones.

I am talking about all possible pairings like:
Adding scalar to existing matrix
I came up with the following:
the_matrix.iter_mut().for_each(|e| *e = *e + the_scalar);
Adding scalar to matrix, producing new matrix
I came up with the following:
the_matrix.map(|e| e + the_scalar);
after having tested many, many horrible things, such as:
&the_matrix + na::DMatrix::from_element(the_matrix.nrows(), the_matrixncols(), 1.0) * the_scalar;

And then I accidentially found add_scalar() in the changelog…

Adding a column-vector to each column of an existing matrix
I came up with the following:
the_matrix.column_iter_mut().for_each(|mut col| col += &the_vector);
Adding a column-vector to each column of a matrix, producing a new matrix
…??

Adding a row-vector to each row of a matrix
the_matrix.row_iter_mut().for_each(|mut row| row += &the_vector);
Adding a row-vector to each row of a matrix, producing a new matrix
…??
Multiplying a column-vector with each column of a matrix, producing a new matrix
etc.

Is there an overview for these arithmetics?

2

Hi! Sorry for the late response.

The only overview we currently have is provided by the quick reference. Though it does lacks some methods (like the add_scalar you mentioned).

Note that for adding a scalar to existing matrix, you can simply use .add_scalar_mut(the_scalar).

I agree it would be great to have those kind of little recipes listed somewhere. I’ve created an issue about this: https://github.com/rustsim/nalgebra.org/issues/28