SpHEAR/calibration/src/sphear_maxr.m

%% -*- mode: octave -*-
%%
%% https://ccrma.stanford.edu/~jos/sasp/Matlab_listing_maxr_m.html
%%
%% MAXR   Find interpolated maximizer(s) and max value(s) 
%%       for (each column of) a.
%%
%%               [xi,yi,hc] = maxr(a) 
%%
%%  Calls max() followed by qint() for quadratic interpolation.
%%  

function [xi,yi,hc] = sphear_maxr(a) 
  [m,n] = size(a); 
  if m==1, a=a'; t=m; m=n; n=t; end; 
  [y,x] = max(a); 
  xi=x;    % vector of maximizer locations, one per col of a
  yi=y;    % vector of maximum values, one per column of a
  if nargout>2, hc = zeros(1,n); end
  for j=1:n,   % loop over columns
    if x(j)>1, % only support interior maxima
      if x(j)<m, 
        [xdelta,yij,cj] = sphear_qint(a(x(j)-1,j),y(j),a(x(j)+1,j)); 
        xi(j) = x(j) + xdelta;
        if nargout>2, hc(j) = cj; end
        if (nargout>1), yi(j) = yij; end
      end; 
    end; 
  end;
end