bfqad bfqad_r bsqad pchia pchid pfqad pfqad_r ppqad

bsqad() void bsqad ( double  t[], double  bcoef[], int  n, int  k, double  x1, double  x2, double *  bquad, double  work[], int *  info  ) Integral of B-representation of B-spline Purpose This routine computes the integral on [x1, x2] of a k-th order B-spline using the B-representation (t[], bcoef[], n, k). Orders k as high as 20 are permitted by applying a 2, 6, or 10 point Gauss formula on subintervals of [x1, x2] which are formed by included (distinct) knots. If orders k greater than 20 are needed, use bfqad with f(x) = 1. Parameters [in] t[] Array t[lt] (lt >= n + k) Knot vector. [in] bcoef() Array bcoef[lbcoef] (lbcoef >= n) B-spline coefficients. [in] n Number of B-spline coefficients. (n = sum of knot multiplicities - k) [in] k Order of B-spline. (1 <= k <= 20) [in] x1 Lower end point of quadrature interval. (t[k] <= x1 <= t[n+1]) [in] x2 Upper end point of quadrature interval. (t[k] <= x2 <= t[n+1]) [out] bquad Integral of the B-spline over [x1, x2]. [out] work[] Array work[lwork] (lwork >= 3*k) Work array. [out] info = 0: Successful exit = -3: The argument n had an illegal value (n < k) = -4: The argument k had an illegal value (k < 1 or k > 20) = -5: The argument x1 had an illegal value (x1 < t[k-1] or x1 > t[n]) = -6: The argument x2 had an illegal value (x2 < t[k-1] or x2 > t[n]) Reference SLATEC