Banfac Banslv Bint4 Bintk Bspldr Bsplev Bsplpp Bsplvd Bsplvn Bvalue Interv Ppvalu

Banfac() Sub Banfac ( N As  Long, Kl As  Long, Ku As  Long, Ab() As  Double, Info As  Long  ) LU factorization of banded coefficient matrix of system of linear equations (support routine for Bint4 and Bintk) Purpose This routine computes the LU factorization (without pivoting) of the banded matrix A of order N with (Kl + 1 + Ku) bands or diagonals. The LU factorized matrix is used by Banslv to compoute the B-spline coefficients by solving the system of linear equations. Banfac and Banslv are the support routines for Bint4 and Bintk. Parameters [in] N Number of linear equations, i.e., order of the matrix A. (N >= 1) [in] Kl Number of sub-diagonals within the band of A. (Kl >= 0) [in] Ku Number of super-diagonals within the band of A. (Ku >= 0) [in,out] Ab() Array Ab(LAb1 - 1, LAb2 - 1) (LAb1 >= Kl + Ku + 1, LAb2 >= N) (2D array) or Ab(LAb - 1) (LAb >= (Kl + Ku + 1)*N) (1D array) [in] The matrix A in band matrix form. [out] The LU factorization of A into a unit lower triangular matrix L and an upper triangular matrix U (both banded) and stored in customary fashion over the corresponding entries of A. [out] Info = 0: Successful exit. = -1: The argument N had an illegal value. (N < 1) = -2: The argument Kl had an illegal value. (Kl < 0) = -3: The argument Ku had an illegal value. (Ku < 0) = -4: The argument Ab() is incalid. = 1: Failed to factorize A. This implies that A is singular. Reference SLATEC