Add tests for CSR accessors

[KyleVaughn]

Description:

The CSR, or Compressed Sparse Row, matrix storage format is a format that can store matrices with many nonzero elements much more efficiently than a full 2D array representation.

An accessor method of a class is a "getter" function, used to output the attributes of an object without directly accessing or altering them, as the attributes are private. Unit tests of these functions will ensure that the proper values are accessed from the object in the proper format

The following attributes must be targets of the accessor:

1. nrows, the number of rows of the matrix (size_t)
2. ncols, the number of columns of the matrix (size_t)
3. nnz, the number of nonzeros in the matrix (size_t)
4. aij, an array of the matrix values (templated as float or double)
5. ja, an array of the column index values corresponding to the values in aij (int)
6. ia, an array of pointers that specify which positions in aij correspond to moving to the next row (int)

Tasks:

• [x] Confirm naming convention with developer of the accessor method

  • [x] Arranged meeting with developer
  • [x] Confirmed convention

• [x] Write unit tests to access each private attribute:

  • [x] nrows
  • [x] ncols
  • [x] nnz
  • [x] aij
  • [x] ja
  • [x] ia
  • [x] Value (querying into aij at a specific coordinate)
    • [x] Nonzero
    • [x] Zero

• [x] Test accessor with the above unit tests

• [x] If applicable, inform accessor developer of failed unit tests for revisions

• [x] Confirm with accessor development when no further changes are required

Definition of done:

This task is done when each task box is checked off. If applicable, each main task box requires all subtask boxes to be checked before completion.

[AndrewPanter]

Issue description ready for review

[nickamano]

This issue looks good. I would say that you should consider some edge cases in accessing like making sure it does not modify the value when accessing or something like that but generally looks good.

[nickamano]

I added my comments to the implementation CSR accessors pr but after review it looked good and I was able to pull and make without any issues.