refector: make the sampling module more independent

This commit is contained in:
leejet 2024-06-10 22:42:15 +08:00
parent b6daf5c55b
commit 08f5b41956
2 changed files with 401 additions and 385 deletions

View File

@ -261,4 +261,402 @@ struct CompVisVDenoiser : public Denoiser {
}
};
typedef std::function<ggml_tensor*(ggml_tensor*, float, int)> denoise_cb_t;
// k diffusion reverse ODE: dx = (x - D(x;\sigma)) / \sigma dt; \sigma(t) = t
void sample_k_diffusion(sample_method_t method,
denoise_cb_t model,
ggml_context* work_ctx,
ggml_tensor* x,
std::vector<float> sigmas,
std::shared_ptr<RNG> rng) {
size_t steps = sigmas.size() - 1;
// sample_euler_ancestral
switch (method) {
case EULER_A: {
struct ggml_tensor* noise = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
float sigma = sigmas[i];
// denoise
ggml_tensor* denoised = model(x, sigma, i + 1);
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int i = 0; i < ggml_nelements(d); i++) {
vec_d[i] = (vec_x[i] - vec_denoised[i]) / sigma;
}
}
// get_ancestral_step
float sigma_up = std::min(sigmas[i + 1],
std::sqrt(sigmas[i + 1] * sigmas[i + 1] * (sigmas[i] * sigmas[i] - sigmas[i + 1] * sigmas[i + 1]) / (sigmas[i] * sigmas[i])));
float sigma_down = std::sqrt(sigmas[i + 1] * sigmas[i + 1] - sigma_up * sigma_up);
// Euler method
float dt = sigma_down - sigmas[i];
// x = x + d * dt
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int i = 0; i < ggml_nelements(x); i++) {
vec_x[i] = vec_x[i] + vec_d[i] * dt;
}
}
if (sigmas[i + 1] > 0) {
// x = x + noise_sampler(sigmas[i], sigmas[i + 1]) * s_noise * sigma_up
ggml_tensor_set_f32_randn(noise, rng);
// noise = load_tensor_from_file(work_ctx, "./rand" + std::to_string(i+1) + ".bin");
{
float* vec_x = (float*)x->data;
float* vec_noise = (float*)noise->data;
for (int i = 0; i < ggml_nelements(x); i++) {
vec_x[i] = vec_x[i] + vec_noise[i] * sigma_up;
}
}
}
}
} break;
case EULER: // Implemented without any sigma churn
{
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
float sigma = sigmas[i];
// denoise
ggml_tensor* denoised = model(x, sigma, i + 1);
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(d); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigma;
}
}
float dt = sigmas[i + 1] - sigma;
// x = x + d * dt
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
}
}
} break;
case HEUN: {
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* x2 = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
// denoise
ggml_tensor* denoised = model(x, sigmas[i], -(i + 1));
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigmas[i];
}
}
float dt = sigmas[i + 1] - sigmas[i];
if (sigmas[i + 1] == 0) {
// Euler step
// x = x + d * dt
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
} else {
// Heun step
float* vec_d = (float*)d->data;
float* vec_d2 = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_x2 = (float*)x2->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x2[j] = vec_x[j] + vec_d[j] * dt;
}
ggml_tensor* denoised = model(x2, sigmas[i + 1], i + 1);
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
float d2 = (vec_x2[j] - vec_denoised[j]) / sigmas[i + 1];
vec_d[j] = (vec_d[j] + d2) / 2;
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
}
}
} break;
case DPM2: {
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* x2 = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
// denoise
ggml_tensor* denoised = model(x, sigmas[i], i + 1);
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigmas[i];
}
}
if (sigmas[i + 1] == 0) {
// Euler step
// x = x + d * dt
float dt = sigmas[i + 1] - sigmas[i];
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
} else {
// DPM-Solver-2
float sigma_mid = exp(0.5f * (log(sigmas[i]) + log(sigmas[i + 1])));
float dt_1 = sigma_mid - sigmas[i];
float dt_2 = sigmas[i + 1] - sigmas[i];
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_x2 = (float*)x2->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x2[j] = vec_x[j] + vec_d[j] * dt_1;
}
ggml_tensor* denoised = model(x2, sigma_mid, i + 1);
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
float d2 = (vec_x2[j] - vec_denoised[j]) / sigma_mid;
vec_x[j] = vec_x[j] + d2 * dt_2;
}
}
}
} break;
case DPMPP2S_A: {
struct ggml_tensor* noise = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* x2 = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
// denoise
ggml_tensor* denoised = model(x, sigmas[i], i + 1);
// get_ancestral_step
float sigma_up = std::min(sigmas[i + 1],
std::sqrt(sigmas[i + 1] * sigmas[i + 1] * (sigmas[i] * sigmas[i] - sigmas[i + 1] * sigmas[i + 1]) / (sigmas[i] * sigmas[i])));
float sigma_down = std::sqrt(sigmas[i + 1] * sigmas[i + 1] - sigma_up * sigma_up);
auto t_fn = [](float sigma) -> float { return -log(sigma); };
auto sigma_fn = [](float t) -> float { return exp(-t); };
if (sigma_down == 0) {
// Euler step
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(d); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigmas[i];
}
// TODO: If sigma_down == 0, isn't this wrong?
// But
// https://github.com/crowsonkb/k-diffusion/blob/master/k_diffusion/sampling.py#L525
// has this exactly the same way.
float dt = sigma_down - sigmas[i];
for (int j = 0; j < ggml_nelements(d); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
} else {
// DPM-Solver++(2S)
float t = t_fn(sigmas[i]);
float t_next = t_fn(sigma_down);
float h = t_next - t;
float s = t + 0.5f * h;
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_x2 = (float*)x2->data;
float* vec_denoised = (float*)denoised->data;
// First half-step
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x2[j] = (sigma_fn(s) / sigma_fn(t)) * vec_x[j] - (exp(-h * 0.5f) - 1) * vec_denoised[j];
}
ggml_tensor* denoised = model(x2, sigmas[i + 1], i + 1);
// Second half-step
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = (sigma_fn(t_next) / sigma_fn(t)) * vec_x[j] - (exp(-h) - 1) * vec_denoised[j];
}
}
// Noise addition
if (sigmas[i + 1] > 0) {
ggml_tensor_set_f32_randn(noise, rng);
{
float* vec_x = (float*)x->data;
float* vec_noise = (float*)noise->data;
for (int i = 0; i < ggml_nelements(x); i++) {
vec_x[i] = vec_x[i] + vec_noise[i] * sigma_up;
}
}
}
}
} break;
case DPMPP2M: // DPM++ (2M) from Karras et al (2022)
{
struct ggml_tensor* old_denoised = ggml_dup_tensor(work_ctx, x);
auto t_fn = [](float sigma) -> float { return -log(sigma); };
for (int i = 0; i < steps; i++) {
// denoise
ggml_tensor* denoised = model(x, sigmas[i], i + 1);
float t = t_fn(sigmas[i]);
float t_next = t_fn(sigmas[i + 1]);
float h = t_next - t;
float a = sigmas[i + 1] / sigmas[i];
float b = exp(-h) - 1.f;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
float* vec_old_denoised = (float*)old_denoised->data;
if (i == 0 || sigmas[i + 1] == 0) {
// Simpler step for the edge cases
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = a * vec_x[j] - b * vec_denoised[j];
}
} else {
float h_last = t - t_fn(sigmas[i - 1]);
float r = h_last / h;
for (int j = 0; j < ggml_nelements(x); j++) {
float denoised_d = (1.f + 1.f / (2.f * r)) * vec_denoised[j] - (1.f / (2.f * r)) * vec_old_denoised[j];
vec_x[j] = a * vec_x[j] - b * denoised_d;
}
}
// old_denoised = denoised
for (int j = 0; j < ggml_nelements(x); j++) {
vec_old_denoised[j] = vec_denoised[j];
}
}
} break;
case DPMPP2Mv2: // Modified DPM++ (2M) from https://github.com/AUTOMATIC1111/stable-diffusion-webui/discussions/8457
{
struct ggml_tensor* old_denoised = ggml_dup_tensor(work_ctx, x);
auto t_fn = [](float sigma) -> float { return -log(sigma); };
for (int i = 0; i < steps; i++) {
// denoise
ggml_tensor* denoised = model(x, sigmas[i], i + 1);
float t = t_fn(sigmas[i]);
float t_next = t_fn(sigmas[i + 1]);
float h = t_next - t;
float a = sigmas[i + 1] / sigmas[i];
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
float* vec_old_denoised = (float*)old_denoised->data;
if (i == 0 || sigmas[i + 1] == 0) {
// Simpler step for the edge cases
float b = exp(-h) - 1.f;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = a * vec_x[j] - b * vec_denoised[j];
}
} else {
float h_last = t - t_fn(sigmas[i - 1]);
float h_min = std::min(h_last, h);
float h_max = std::max(h_last, h);
float r = h_max / h_min;
float h_d = (h_max + h_min) / 2.f;
float b = exp(-h_d) - 1.f;
for (int j = 0; j < ggml_nelements(x); j++) {
float denoised_d = (1.f + 1.f / (2.f * r)) * vec_denoised[j] - (1.f / (2.f * r)) * vec_old_denoised[j];
vec_x[j] = a * vec_x[j] - b * denoised_d;
}
}
// old_denoised = denoised
for (int j = 0; j < ggml_nelements(x); j++) {
vec_old_denoised[j] = vec_denoised[j];
}
}
} break;
case LCM: // Latent Consistency Models
{
struct ggml_tensor* noise = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
float sigma = sigmas[i];
// denoise
ggml_tensor* denoised = model(x, sigma, i + 1);
// x = denoised
{
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_denoised[j];
}
}
if (sigmas[i + 1] > 0) {
// x += sigmas[i + 1] * noise_sampler(sigmas[i], sigmas[i + 1])
ggml_tensor_set_f32_randn(noise, rng);
// noise = load_tensor_from_file(res_ctx, "./rand" + std::to_string(i+1) + ".bin");
{
float* vec_x = (float*)x->data;
float* vec_noise = (float*)noise->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + sigmas[i + 1] * vec_noise[j];
}
}
}
}
} break;
default:
LOG_ERROR("Attempting to sample with nonexisting sample method %i", method);
abort();
}
}
#endif // __DENOISER_HPP__

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@ -877,7 +877,7 @@ public:
}
struct ggml_tensor* denoised = ggml_dup_tensor(work_ctx, x);
auto denoise = [&](ggml_tensor* input, float sigma, int step) {
auto denoise = [&](ggml_tensor* input, float sigma, int step) -> ggml_tensor* {
if (step == 1) {
pretty_progress(0, (int)steps, 0);
}
@ -983,393 +983,11 @@ public:
pretty_progress(step, (int)steps, (t1 - t0) / 1000000.f);
// LOG_INFO("step %d sampling completed taking %.2fs", step, (t1 - t0) * 1.0f / 1000000);
}
return denoised;
};
// sample_euler_ancestral
switch (method) {
case EULER_A: {
struct ggml_tensor* noise = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
sample_k_diffusion(method, denoise, work_ctx, x, sigmas, rng);
for (int i = 0; i < steps; i++) {
float sigma = sigmas[i];
// denoise
denoise(x, sigma, i + 1);
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int i = 0; i < ggml_nelements(d); i++) {
vec_d[i] = (vec_x[i] - vec_denoised[i]) / sigma;
}
}
// get_ancestral_step
float sigma_up = std::min(sigmas[i + 1],
std::sqrt(sigmas[i + 1] * sigmas[i + 1] * (sigmas[i] * sigmas[i] - sigmas[i + 1] * sigmas[i + 1]) / (sigmas[i] * sigmas[i])));
float sigma_down = std::sqrt(sigmas[i + 1] * sigmas[i + 1] - sigma_up * sigma_up);
// Euler method
float dt = sigma_down - sigmas[i];
// x = x + d * dt
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int i = 0; i < ggml_nelements(x); i++) {
vec_x[i] = vec_x[i] + vec_d[i] * dt;
}
}
if (sigmas[i + 1] > 0) {
// x = x + noise_sampler(sigmas[i], sigmas[i + 1]) * s_noise * sigma_up
ggml_tensor_set_f32_randn(noise, rng);
// noise = load_tensor_from_file(work_ctx, "./rand" + std::to_string(i+1) + ".bin");
{
float* vec_x = (float*)x->data;
float* vec_noise = (float*)noise->data;
for (int i = 0; i < ggml_nelements(x); i++) {
vec_x[i] = vec_x[i] + vec_noise[i] * sigma_up;
}
}
}
}
} break;
case EULER: // Implemented without any sigma churn
{
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
float sigma = sigmas[i];
// denoise
denoise(x, sigma, i + 1);
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(d); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigma;
}
}
float dt = sigmas[i + 1] - sigma;
// x = x + d * dt
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
}
}
} break;
case HEUN: {
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* x2 = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
// denoise
denoise(x, sigmas[i], -(i + 1));
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigmas[i];
}
}
float dt = sigmas[i + 1] - sigmas[i];
if (sigmas[i + 1] == 0) {
// Euler step
// x = x + d * dt
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
} else {
// Heun step
float* vec_d = (float*)d->data;
float* vec_d2 = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_x2 = (float*)x2->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x2[j] = vec_x[j] + vec_d[j] * dt;
}
denoise(x2, sigmas[i + 1], i + 1);
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
float d2 = (vec_x2[j] - vec_denoised[j]) / sigmas[i + 1];
vec_d[j] = (vec_d[j] + d2) / 2;
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
}
}
} break;
case DPM2: {
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* x2 = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
// denoise
denoise(x, sigmas[i], i + 1);
// d = (x - denoised) / sigma
{
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigmas[i];
}
}
if (sigmas[i + 1] == 0) {
// Euler step
// x = x + d * dt
float dt = sigmas[i + 1] - sigmas[i];
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
} else {
// DPM-Solver-2
float sigma_mid = exp(0.5f * (log(sigmas[i]) + log(sigmas[i + 1])));
float dt_1 = sigma_mid - sigmas[i];
float dt_2 = sigmas[i + 1] - sigmas[i];
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_x2 = (float*)x2->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x2[j] = vec_x[j] + vec_d[j] * dt_1;
}
denoise(x2, sigma_mid, i + 1);
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
float d2 = (vec_x2[j] - vec_denoised[j]) / sigma_mid;
vec_x[j] = vec_x[j] + d2 * dt_2;
}
}
}
} break;
case DPMPP2S_A: {
struct ggml_tensor* noise = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* x2 = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
// denoise
denoise(x, sigmas[i], i + 1);
// get_ancestral_step
float sigma_up = std::min(sigmas[i + 1],
std::sqrt(sigmas[i + 1] * sigmas[i + 1] * (sigmas[i] * sigmas[i] - sigmas[i + 1] * sigmas[i + 1]) / (sigmas[i] * sigmas[i])));
float sigma_down = std::sqrt(sigmas[i + 1] * sigmas[i + 1] - sigma_up * sigma_up);
auto t_fn = [](float sigma) -> float { return -log(sigma); };
auto sigma_fn = [](float t) -> float { return exp(-t); };
if (sigma_down == 0) {
// Euler step
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(d); j++) {
vec_d[j] = (vec_x[j] - vec_denoised[j]) / sigmas[i];
}
// TODO: If sigma_down == 0, isn't this wrong?
// But
// https://github.com/crowsonkb/k-diffusion/blob/master/k_diffusion/sampling.py#L525
// has this exactly the same way.
float dt = sigma_down - sigmas[i];
for (int j = 0; j < ggml_nelements(d); j++) {
vec_x[j] = vec_x[j] + vec_d[j] * dt;
}
} else {
// DPM-Solver++(2S)
float t = t_fn(sigmas[i]);
float t_next = t_fn(sigma_down);
float h = t_next - t;
float s = t + 0.5f * h;
float* vec_d = (float*)d->data;
float* vec_x = (float*)x->data;
float* vec_x2 = (float*)x2->data;
float* vec_denoised = (float*)denoised->data;
// First half-step
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x2[j] = (sigma_fn(s) / sigma_fn(t)) * vec_x[j] - (exp(-h * 0.5f) - 1) * vec_denoised[j];
}
denoise(x2, sigmas[i + 1], i + 1);
// Second half-step
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = (sigma_fn(t_next) / sigma_fn(t)) * vec_x[j] - (exp(-h) - 1) * vec_denoised[j];
}
}
// Noise addition
if (sigmas[i + 1] > 0) {
ggml_tensor_set_f32_randn(noise, rng);
{
float* vec_x = (float*)x->data;
float* vec_noise = (float*)noise->data;
for (int i = 0; i < ggml_nelements(x); i++) {
vec_x[i] = vec_x[i] + vec_noise[i] * sigma_up;
}
}
}
}
} break;
case DPMPP2M: // DPM++ (2M) from Karras et al (2022)
{
struct ggml_tensor* old_denoised = ggml_dup_tensor(work_ctx, x);
auto t_fn = [](float sigma) -> float { return -log(sigma); };
for (int i = 0; i < steps; i++) {
// denoise
denoise(x, sigmas[i], i + 1);
float t = t_fn(sigmas[i]);
float t_next = t_fn(sigmas[i + 1]);
float h = t_next - t;
float a = sigmas[i + 1] / sigmas[i];
float b = exp(-h) - 1.f;
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
float* vec_old_denoised = (float*)old_denoised->data;
if (i == 0 || sigmas[i + 1] == 0) {
// Simpler step for the edge cases
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = a * vec_x[j] - b * vec_denoised[j];
}
} else {
float h_last = t - t_fn(sigmas[i - 1]);
float r = h_last / h;
for (int j = 0; j < ggml_nelements(x); j++) {
float denoised_d = (1.f + 1.f / (2.f * r)) * vec_denoised[j] - (1.f / (2.f * r)) * vec_old_denoised[j];
vec_x[j] = a * vec_x[j] - b * denoised_d;
}
}
// old_denoised = denoised
for (int j = 0; j < ggml_nelements(x); j++) {
vec_old_denoised[j] = vec_denoised[j];
}
}
} break;
case DPMPP2Mv2: // Modified DPM++ (2M) from https://github.com/AUTOMATIC1111/stable-diffusion-webui/discussions/8457
{
struct ggml_tensor* old_denoised = ggml_dup_tensor(work_ctx, x);
auto t_fn = [](float sigma) -> float { return -log(sigma); };
for (int i = 0; i < steps; i++) {
// denoise
denoise(x, sigmas[i], i + 1);
float t = t_fn(sigmas[i]);
float t_next = t_fn(sigmas[i + 1]);
float h = t_next - t;
float a = sigmas[i + 1] / sigmas[i];
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
float* vec_old_denoised = (float*)old_denoised->data;
if (i == 0 || sigmas[i + 1] == 0) {
// Simpler step for the edge cases
float b = exp(-h) - 1.f;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = a * vec_x[j] - b * vec_denoised[j];
}
} else {
float h_last = t - t_fn(sigmas[i - 1]);
float h_min = std::min(h_last, h);
float h_max = std::max(h_last, h);
float r = h_max / h_min;
float h_d = (h_max + h_min) / 2.f;
float b = exp(-h_d) - 1.f;
for (int j = 0; j < ggml_nelements(x); j++) {
float denoised_d = (1.f + 1.f / (2.f * r)) * vec_denoised[j] - (1.f / (2.f * r)) * vec_old_denoised[j];
vec_x[j] = a * vec_x[j] - b * denoised_d;
}
}
// old_denoised = denoised
for (int j = 0; j < ggml_nelements(x); j++) {
vec_old_denoised[j] = vec_denoised[j];
}
}
} break;
case LCM: // Latent Consistency Models
{
struct ggml_tensor* noise = ggml_dup_tensor(work_ctx, x);
struct ggml_tensor* d = ggml_dup_tensor(work_ctx, x);
for (int i = 0; i < steps; i++) {
float sigma = sigmas[i];
// denoise
denoise(x, sigma, i + 1);
// x = denoised
{
float* vec_x = (float*)x->data;
float* vec_denoised = (float*)denoised->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_denoised[j];
}
}
if (sigmas[i + 1] > 0) {
// x += sigmas[i + 1] * noise_sampler(sigmas[i], sigmas[i + 1])
ggml_tensor_set_f32_randn(noise, rng);
// noise = load_tensor_from_file(res_ctx, "./rand" + std::to_string(i+1) + ".bin");
{
float* vec_x = (float*)x->data;
float* vec_noise = (float*)noise->data;
for (int j = 0; j < ggml_nelements(x); j++) {
vec_x[j] = vec_x[j] + sigmas[i + 1] * vec_noise[j];
}
}
}
}
} break;
default:
LOG_ERROR("Attempting to sample with nonexisting sample method %i", method);
abort();
}
if (control_net) {
control_net->free_control_ctx();
control_net->free_compute_buffer();