Question

我正在使用以下代码获得'gsl：interp.c：150：错误：插值错误'。一些谷歌搜索说，当你尝试使用interp函数进行推断时会发生这种错误，但我不知道这是怎么回事。非常感谢帮助。感谢。

函数randomground()只返回一个随机数（double）。

#define NSTEPS 100   

int main()
{
           int j, q, space = 1, refine = 100;
           double xi = 0.0, tx[2*NSTEPS] = {0}, theight[2*NSTEPS] = {0};

           double terrain[(int) (2*NSTEPS*100)] = {0};
           double terrainsl[(int) (2*NSTEPS*100)] = {0};

            for (j = 0; j < 2*NSTEPS; j++)
            {
                tx[j] = (double) j*space;
                theight[j] = randomground();
            }

            gsl_interp_accel *acc = gsl_interp_accel_alloc();
            gsl_spline *spline = gsl_spline_alloc(gsl_interp_akima, 2*NSTEPS);
            gsl_spline_init(spline, tx, theight, 2*NSTEPS);

            for (q = 0; q< 2*NSTEPS*100; q++)
            {
                terrain[q] = gsl_spline_eval(spline,xi,acc);
                terrainsl[q] = gsl_spline_eval_deriv(spline,xi,acc);
                xi = xi+(double) space/refine;
            }
return 0;
}

Answer 1

通过向tx和theight添加额外元素来解决问题。我猜这是你要我做的，@ ViniciusMiranda。代码现在读取

                double tx[2*NSTEPS+1] = {0}, theight[2*NSTEPS+1] = {0};
                double terrain[(int) (2*NSTEPS*100)] = {0};
                double terrainsl[(int) (2*NSTEPS*100)] = {0};

            for (j = 0; j < 2*NSTEPS+1; j++)
            {
                tx[j] = (double) j*space;
                theight[j] = randomground();
            }

            gsl_interp_accel *acc = gsl_interp_accel_alloc();
            gsl_spline *spline = gsl_spline_alloc(gsl_interp_akima, 2*NSTEPS+1);
            gsl_spline_init(spline, tx, theight, 2*NSTEPS+1);

            for (q = 0; q< 2*NSTEPS*100; q++)
            {
                terrain[q] = gsl_spline_eval(spline,xi,acc);
                terrainsl[q] = gsl_spline_eval_deriv(spline,xi,acc);
                xi = xi+(double) space/refine;
            }

我仍然不明白为什么这个修复是必需的。

Answer 2

Akima样条曲线是局部的子样条插值。对于函数f(x)，如果您要为x获取x_i <= x <= x_i+1的值，则Akima样条线需要(x_j, f_j)的对j = i-2, i-1, i, i+1, i+2, i+3.

Answer 3

我在代码zigzag.sourceforge.net中发现了相同的错误，并通过注释gsl library source中的行，对其进行编译并重新安装来解决。

在版本1.14之前，interp.c中的第150行

// GSL_ERROR_VAL("interpolation error", GSL_EDOM, GSL_NAN);

我发表评论以解决中断问题！

gsl akima样条的插值误差

3 个答案: