lossfun_hist1.m

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% Created by Jonathan T Barron and Jitendra Malik, Electrical Engineering
% and Computer Science, University of California, Berkeley.
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function [loss, d_loss_Fpyr] = lossfun_hist3(Fpyr, X_splat, lambda_smooth, robust_cost, pyr_meta)

F = pyr_meta.AcT * Fpyr;

P = exp(-F);
Z = sum(P(:));
logZ = log(Z);
d_logZ = -P ./ max(eps,sum(P(:)));
loss_data = sum(sum(F .* X_splat.N)) + logZ;

loss = loss_data;
d_loss_F = X_splat.N + d_logZ;

f = [1; -2; 1];

Jxx = convn(F, f, 'valid');

mult = lambda_smooth/numel(F);

J = Jxx.^2;

if robust_cost
  
  sqrt_J = sqrt(J + 0.00001);
  loss_smooth = mult * sum(sqrt_J(:));
  loss = loss + loss_smooth;
  
  d_Jxx = convn(Jxx./sqrt_J, f(end:-1:1), 'full');
  
else
  
  loss_smooth = mult * 0.5*sum(J(:));
  loss = loss + loss_smooth;
  
  d_Jxx = convn(Jxx, f(end:-1:1), 'full');
  
end

d_loss_F = d_loss_F + mult * d_Jxx;

d_loss_Fpyr = pyr_meta.Ac * d_loss_F;


global last_display
if isempty(last_display) || (etime(clock, last_display) > .1)
  last_display = clock;
  plot(F); drawnow;
end