/// <summary>
/// Determines whether defined matrix is diagonal matrix or not.
/// Diagonal matrix is a matrix that only have nonzero elements on its main diagonal.
/// </summary>
/// <param name="mtx">The MTX.</param>
/// <returns></returns>
public static bool IsDiagonalMatrix(this CCS mtx)
{
var n = mtx.ColumnCount;
if (n != mtx.RowCount)
{
return(false);
}
if (mtx.Values.Length > n)
{
return(false);
}
for (int i = 0; i < n; i++)
{
var col = i;
var st = mtx.ColumnPointers[i];
var en = mtx.ColumnPointers[i + 1];
for (int j = st; j < en; j++)
{
var row = mtx.RowIndices[j];
if (row != col)
{
return(false);
}
}
}
return(true);
}
/// <summary>
/// Gets the reduced zone divided matrix.
/// </summary>
/// <param name="reducedMatrix">The reduced matrix.</param>
/// <param name="map">The map.</param>
/// <returns></returns>
public static ZoneDevidedMatrix GetReducedZoneDividedMatrix(CCS reducedMatrix, DofMappingManager map)
{
var m = map.M;
var n = map.N;
var r = reducedMatrix;
if (r.ColumnCount != r.RowCount || r.RowCount != 6 * m)
{
throw new InvalidOperationException();
}
var ff = new Coord(map.RMap2.Length, map.RMap2.Length);
var fs = new Coord(map.RMap2.Length, map.RMap3.Length);
var sf = new Coord(map.RMap3.Length, map.RMap2.Length);
var ss = new Coord(map.RMap3.Length, map.RMap3.Length);
for (var i = 0; i < 6 * m; i++)
{
var st = r.ColumnPointers[i];
var en = r.ColumnPointers[i + 1];
var col = i;
for (var j = st; j < en; j++)
{
var row = r.RowIndices[j];
var val = r.Values[j];
if (map.Fixity[map.RMap1[row]] == DofConstraint.Released &&
map.Fixity[map.RMap1[col]] == DofConstraint.Released)
{
ff.At(map.Map2[row], map.Map2[col], val);
}
if (map.Fixity[map.RMap1[row]] == DofConstraint.Released &&
map.Fixity[map.RMap1[col]] != DofConstraint.Released)
{
fs.At(map.Map2[row], map.Map3[col], val);
}
if (map.Fixity[map.RMap1[row]] != DofConstraint.Released &&
map.Fixity[map.RMap1[col]] == DofConstraint.Released)
{
sf.At(map.Map3[row], map.Map2[col], val);
}
if (map.Fixity[map.RMap1[row]] != DofConstraint.Released &&
map.Fixity[map.RMap1[col]] != DofConstraint.Released)
{
ss.At(map.Map3[row], map.Map3[col], val);
}
}
}
var buf = new ZoneDevidedMatrix();
buf.ReleasedReleasedPart = ff.ToCCs();
buf.ReleasedFixedPart = fs.ToCCs();
buf.FixedReleasedPart = sf.ToCCs();
buf.FixedFixedPart = ss.ToCCs();
return(buf);
}
