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ircd::gpt: Backpropagate adaptive moment estimations.

This commit is contained in:
Jason Volk 2021-04-22 12:20:58 -07:00
parent da5fa1217a
commit 1f49f71530

View file

@ -10,6 +10,16 @@
namespace ircd::gpt
{
static size_t adamw(f32x4 &, f32x4 &, f32x4 &, const f32, const f32, const f32, const f32, const u32, size_t);
static size_t adamw(task &, const f32, f32 *, const size_t, f32 *const (&)[2], const size_t);
static size_t backprop(task &, const f32, model::norm &, f32 *const (&)[2], size_t);
static size_t backprop(task &, const f32, model::attn &, f32 *const (&)[2], size_t);
static size_t backprop(task &, const f32, model::ffnn &, f32 *const (&)[2], size_t);
static size_t backprop(task &, const f32, model::block &, f32 *const (&)[2], size_t);
static size_t backprop(task &, const f32, model::embed &, f32 *const (&)[2], size_t);
static size_t backprop(task &, const f32, model::decoder &, f32 *const (&)[2], size_t = 0);
template<class T>
static void fmma(T *out, const T *in, const T *bias, const T *weight, const math::fmma_opts &);
@ -141,6 +151,50 @@ ircd::gpt::generate(const vector_view<u16> &out,
}
uint64_t cycles(0);
if(ctrl.prop)
{
static f32 *_momentum[2];
if(!_momentum[0])
{
_momentum[0] = new f32[sizeof(model::decoder) / 4] {0.0f};
_momentum[1] = new f32[sizeof(model::decoder) / 4] {0.0f};
}
f32 *const momentum[2]
{
_momentum[0], _momentum[1],
};
const prof::scope_cycles task_cycles
{
cycles
};
backprop(task, ctrl.loss_mean, *model::default_model, momentum);
}
if(ctrl.prop)
{
log::debug
{
log, "Backpropagation of %2.6f in %lu cycles.",
ctrl.loss_mean,
cycles,
};
ctrl.epoch = 0;
ctrl.loss_mean = 0;
ctrl.loss = ctrl.loss_mean;
ctrl.perp_mean = 0;
ctrl.perp = ctrl.perp_mean;
ctrl.cert_mean = 0;
ctrl.cert = ctrl.cert_mean;
ctrl.prop = false;
pipe::default_model->invalid = true;
return {};
}
cycles = 0;
milliseconds last_time {0};
util::timer stopwatch;
{
@ -631,6 +685,206 @@ ircd::gpt::gelu(f32x4 &out,
out = 0.5 * in * (1.0 + tanh(in * f32(0.7978845608) * (1.0 + f32(0.044715) * in * in)));
}
//
// backside
//
size_t
ircd::gpt::backprop(task &task,
const f32 grad,
model::decoder &param,
f32 *const (&moment)[2],
size_t off)
{
for(uint i(0); i < 12; ++i)
off = backprop(task, grad, param.layer[i], moment, off);
off = backprop(task, grad, param.f, moment, off);
off = backprop(task, grad, param.word, moment, off);
return off;
}
size_t
ircd::gpt::backprop(task &task,
const f32 grad,
model::embed &param,
f32 *const (&moment)[2],
size_t off)
{
assert(task.opts);
const auto &opts
{
*task.opts
};
for(uint i(0); i < opts.context_tokens; ++i)
off = adamw(task, grad, param.pos[i], 768, moment, off);
for(uint i(0); i < opts.logits; ++i)
off = adamw(task, grad, param.token[i], 768, moment, off);
return off;
}
size_t
ircd::gpt::backprop(task &task,
const f32 grad,
model::block &param,
f32 *const (&moment)[2],
size_t off)
{
off = backprop(task, grad, param.ln1, moment, off);
off = backprop(task, grad, param.attn, moment, off);
off = backprop(task, grad, param.ln2, moment, off);
off = backprop(task, grad, param.ffnn, moment, off);
return off;
}
size_t
ircd::gpt::backprop(task &task,
const f32 grad,
model::attn &param,
f32 *const (&moment)[2],
size_t off)
{
off = adamw(task, grad, param.attn_bias, 2304, moment, off);
for(uint i(0); i < 768; ++i)
off = adamw(task, grad, param.attn_weight[i], 2304, moment, off);
off = adamw(task, grad, param.proj_bias, 768, moment, off);
for(uint i(0); i < 768; ++i)
off = adamw(task, grad, param.proj_weight[i], 768, moment, off);
return off;
}
size_t
ircd::gpt::backprop(task &task,
const f32 grad,
model::ffnn &param,
f32 *const (&moment)[2],
size_t off)
{
off = adamw(task, grad, param.fc_bias, 3072, moment, off);
for(uint i(0); i < 768; ++i)
off = adamw(task, grad, param.fc_weight[i], 3072, moment, off);
off = adamw(task, grad, param.proj_bias, 768, moment, off);
for(uint i(0); i < 3072; ++i)
off = adamw(task, grad, param.proj_weight[i], 768, moment, off);
return off;
}
size_t
ircd::gpt::backprop(task &task,
const f32 grad,
model::norm &param,
f32 *const (&moment)[2],
size_t off)
{
off = adamw(task, grad, param.bias, 768, moment, off);
off = adamw(task, grad, param.weight, 768, moment, off);
return off;
}
size_t
ircd::gpt::adamw(task &task,
const f32 grad,
f32 *const p_,
const size_t num,
f32 *const (&__restrict__ m_)[2],
size_t off)
{
assert(task.opts);
const auto &opts
{
*task.opts
};
assert(task.ctrl);
auto &ctrl
{
*task.ctrl
};
f32x4 *const p[3]
{
reinterpret_cast<f32x4 *>(p_),
reinterpret_cast<f32x4 *>(m_[0]) + off,
reinterpret_cast<f32x4 *>(m_[1]) + off,
};
for(uint i(0); i < num / 4; ++i)
off = adamw(p[0][i], p[1][i], p[2][i], grad, opts.alpha, opts.beta[0], opts.beta[1], ctrl.step, off);
return off;
}
size_t
ircd::gpt::adamw(f32x4 &__restrict__ param,
f32x4 &__restrict__ moment0,
f32x4 &__restrict__ moment1,
const f32 grad,
const f32 alpha,
const f32 beta0,
const f32 beta1,
const u32 step,
const size_t off)
{
const f32x4 one
{
1.0f, 1.0f, 1.0f, 1.0f,
};
const f32x4 a[2]
{
{ one - beta0 },
{ one - beta1 },
};
const f32x4 avg_mul[2]
{
{ moment0 * beta0 },
{ moment1 * beta1 },
};
const f32x4 avg_dot[2]
{
{ avg_mul[0] + a[0] * grad },
{ avg_mul[1] + a[1] * grad * grad },
};
const f32x4 bias[2]
{
{ avg_dot[0] / (one - powf(beta0, step + 1)) },
{ avg_dot[1] / (one - powf(beta1, step + 1)) },
};
const f32x4 denom
{
sqrtf(bias[1]) + 0.000001f // epsilon
};
const f32x4 delta
{
alpha * (bias[0] / denom)
};
const f32x4 update
{
param - delta
};
moment0 = avg_dot[0];
moment1 = avg_dot[1];
param = update;
return off + 1;
}
//
// gpt::task