boussinesq_spline.m

function sigma_z=boussinesq_spline(q,a,b,z)
  % function that determines stress under corner of an a by b rectangular platform
  % z-meters below the platform. The calculated solutions are in the fmn data
  % m=fmn(:,1)
  % in column 2, fmn(:,2), n=1.2
  % in column 3, fmn(:,2), n=1.4
  % in column 4, fmn(:,2), n=1.6

  fmn= [0.1,0.02926,0.03007,0.03058
        0.2,0.05733,0.05894,0.05994
        0.3,0.08323,0.08561,0.08709
        0.4,0.10631,0.10941,0.11135
        0.5,0.12626,0.13003,0.13241
        0.6,0.14309,0.14749,0.15027
        0.7,0.15703,0.16199,0.16515
        0.8,0.16843,0.17389,0.17739];

  m=a/z;
  n=b/z;
  
    sizeF = size(fmn);
  fourM = zeros(4,1);
  fourN = zeros(4,1);
  
  % ----- Finding the range of m ----- %
  i = sizeF(1);
  while m < fmn(i,1)
      i = i - 1;
  end
  
  if i >= 2
    fourM = [fmn(i-1) fmn(i) fmn(i+1) fmn(i+2)]';
  else
    i = 2;
    fourM = [fmn(1) fmn(2) fmn(3) fmn(4)]';
  end
  
  % ---- Can't figure this out ---> interp2(fourM,____,____,m,n)
    
end