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A Delaunay triangulation in the plane with circumcircles shown. In computational geometry, a Delaunay triangulation or Delone triangulation of a set of points in the plane subdivides their convex hull [1] into triangles whose circumcircles do not contain any of the points.
The polar angle is denoted by [,]: it is the angle between the z-axis and the radial vector connecting the origin to the point in question. The azimuthal angle is denoted by φ ∈ [ 0 , 2 π ] {\displaystyle \varphi \in [0,2\pi ]} : it is the angle between the x -axis and the projection of the radial vector onto the xy -plane.
For a symmetric matrix A, the vector vec(A) contains more information than is strictly necessary, since the matrix is completely determined by the symmetry together with the lower triangular portion, that is, the n(n + 1)/2 entries on and below the main diagonal. For such matrices, the half-vectorization is sometimes more useful than the ...
The matrix–vector multiplication can be done in () arithmetical operations where is the average number of nonzero elements in a row. The total complexity is thus O ( d m n ) {\displaystyle O(dmn)} , or O ( d n 2 ) {\displaystyle O(dn^{2})} if m = n {\displaystyle m=n} ; the Lanczos algorithm can be very fast for sparse matrices.
Three examples of the triangle inequality for triangles with sides of lengths x, y, z.The top example shows a case where z is much less than the sum x + y of the other two sides, and the bottom example shows a case where the side z is only slightly less than x + y.
A triangle is a polygon with three corners and three sides, one of the basic shapes in geometry.The corners, also called vertices, are zero-dimensional points while the sides connecting them, also called edges, are one-dimensional line segments.
In mathematics, matrix calculus is a specialized notation for doing multivariable calculus, especially over spaces of matrices.It collects the various partial derivatives of a single function with respect to many variables, and/or of a multivariate function with respect to a single variable, into vectors and matrices that can be treated as single entities.
According to Milne, a free vector is the class of all its representations, a typical representation being defined in the customary manner. From a pedagogic point of view, however, the reviewer wonders whether it might have been better to draw attention at this early stage to a concrete instance of a free vector.