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local MatrixParam = nerv.class('nerv.MatrixParam', 'nerv.Param')
local LinearTransParam = nerv.class('nerv.LinearTransParam', 'nerv.MatrixParam')
local BiasParam = nerv.class('nerv.BiasParam', 'nerv.MatrixParam')
local AffineLayer = nerv.class('nerv.AffineLayer', 'nerv.Layer')
function MatrixParam:read(handle)
self.trans = self.gconf.cumat_type.new_from_host(
nerv.MMatrixFloat.load(handle))
end
function MatrixParam:write(handle)
self.trans:new_to_host():save(handle)
end
function MatrixParam:train_init()
self.correction = self.trans:create()
self.correction:fill(0)
end
function MatrixParam:update(gradient)
local gconf = self.gconf
self.correction:add(self.correction, gradient, gconf.momentum, 1.0)
-- momentum gain
local mmt_gain = 1.0 / (1.0 - gconf.momentum);
local n = self.gconf.batch_size * mmt_gain
-- perform update
self.trans:add(self.trans, self.correction, 1.0, -gconf.lrate / n)
end
function LinearTransParam:update(gradient)
MatrixParam.update(self, gradient)
local gconf = self.gconf
-- weight decay
self.trans:add(self.trans, self.trans, 1.0, -gconf.lrate * gconf.wcost)
end
function AffineLayer:__init(id, global_conf, layer_conf)
self.id = id
self.ltp = layer_conf.ltp
self.bp = layer_conf.bp
self.dim_in = layer_conf.dim_in
self.dim_out = layer_conf.dim_out
self.gconf = global_conf
self:check_dim_len(1, 1) -- exactly one input and one output
self.direct_update = layer_conf.direct_update
end
function AffineLayer:init(batch_size)
if self.ltp.trans:ncol() ~= self.bp.trans:ncol() then
nerv.error("mismatching dimensions of linear transform and bias paramter")
end
if self.dim_in[1] ~= self.ltp.trans:nrow() then
nerv.error("mismatching dimensions of linear transform parameter and input")
end
if self.dim_out[1] ~= self.ltp.trans:ncol() then
nerv.error("mismatching dimensions of linear transform parameter and output")
end
self.ltp_grad = self.ltp.trans:create()
self.ltp:train_init()
self.bp:train_init()
end
function AffineLayer:update(bp_err, input, output)
if self.direct_update then
self.ltp.correction:mul(input[1], bp_err[1], 1.0, gconf.momentum, 'T', 'N')
-- momentum gain
local mmt_gain = 1.0 / (1.0 - gconf.momentum);
local n = self.gconf.batch_size * mmt_gain
-- perform update
self.ltp.trans:add(self.ltp.trans, self.ltp.correction, 1.0, -gconf.lrate / n)
else
self.ltp_grad:mul(input[1], bp_err[1], 1.0, 0.0, 'T', 'N')
self.ltp:update(self.ltp_grad)
end
self.bp:update(bp_err[1]:colsum())
end
function AffineLayer:propagate(input, output)
-- apply linear transform
output[1]:mul(input[1], self.ltp.trans, 1.0, 0.0, 'N', 'N')
-- add bias
output[1]:add_row(self.bp.trans, 1.0)
end
function AffineLayer:back_propagate(bp_err, next_bp_err, input, output)
next_bp_err[1]:mul(bp_err[1], self.ltp.trans, 1.0, 0.0, 'N', 'T')
end
function AffineLayer:get_params()
return nerv.ParamRepo({self.ltp, self.bp})
end
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