Lodestar.Abstractions 0.2.0. This page is frozen at that release. Read the current documentation for what main says now. A link to a decision or a migration page follows main, and leaves the archive.

Home › The shared sparse primitive

CsrMatrix.CreateUnchecked

Builds a matrix from raw arrays without the structural pass the constructor runs — for a producer whose arrays are valid by construction.

public static CsrMatrix CreateUnchecked(int rowCount, int columnCount, double[] values, int[] columnIndices, int[] rowPointers)

Parameters — rowCount and columnCount are the shape. values holds the stored entries row by row, columnIndices the column of each, and rowPointers where each row starts in values, followed by the total — rowCount + 1 entries.

Returns — a CsrMatrix that shares the three arrays rather than copying them.

Exceptions — ArgumentNullException when an array is null. ArgumentOutOfRangeException when a dimension is negative. ArgumentException when rowPointers is not rowCount + 1 long, or values and columnIndices differ in length.

Example — two rows built by hand, the same matrix the constructor would have validated.

using Lodestar.Abstractions;

CsrMatrix matrix = CsrMatrix.CreateUnchecked(2, 3, [1.0, 2.0, 3.0], [0, 2, 1], [0, 2, 3]);

int rows = matrix.RowCount;                  // => 2
double first = matrix.RowL1Norm(0);          // => 3

Remarks — unvalidated, and that is the whole difference from the constructor. The length and null checks run; the per-entry pass does not. Row pointers that decrease, a column index at or past columnCount, or a pointer past the stored values are accepted here and surface later — as a wrong product, or as an IndexOutOfRangeException from whichever member reads the bad entry first.

Reach for it only when the arrays come from your own code and are correct by the way they were built: CountVectorizer and the other vectorizers call it on arrays they have just filled. Anything read from a file, a network or a caller goes through the constructor, which refuses every malformed shape.

Public since 0.2.0. It was internal before, reached by Lodestar.Text through an InternalsVisibleTo this package no longer grants (decision 0003); the signature did not change, so a Lodestar.Text built against 0.1.x still binds to it.

Applies to — net10.0, netstandard2.0.

See also — CsrMatrix, CsrMatrix.ToDense, CountVectorizer.