#include<cmath>
using namespace std;

#define NLAYERS_BCAL 10
double BCAL_tavg(double geometric_mean, int layer)
{
	double tw_par[NLAYERS_BCAL][7] ={
		{-459.766, 395.09, -109.524, 4.07107, 3.27126, -0.570532, 0.0289241},	// layer 1
		{-166.434, 159.853, -49.2921, 2.99389, 1.2468, -0.240305, 0.0125993},	// layer 2
		{-5308.4, 6622.19, -3395.04, 916.852, -137.711, 10.9177, -0.3572},	// layer 3
		{-364.24, 299.521, -78.2711, 1.33324, 2.75256, -0.453378, 0.0226098},	// layer 4
		{-535.03, 291.228, -7.85333, -14.0913, -0.558188, 0.866452, -0.084593},	// layer 5
		{-567.193, 497.169, -134.606, 0.373489, 5.88215, -0.979443, 0.0501939},	// layer 6
		{-976.009, 506.107, -5.20957, -24.8803, -1.49409, 1.57834, -0.147959},	// layer 7
		{0, 0, 0, 0, 0, 0, 0},	// layer 8
		{0, 0, 0, 0, 0, 0, 0},	// layer 9
		{0, 0, 0, 0, 0, 0, 0}	// layer 10
		};

	layer = layer<1 ? 1:layer>NLAYERS_BCAL ? NLAYERS_BCAL:layer;
	double *p = tw_par[layer-1];
	double x = log(geometric_mean);
	return p[0]+x*(p[1]+x*(p[2]+x*(p[3]+x*(p[4]+x*(p[5]+x*p[6])))));
}