/**
* Proximal function for f(z) = 0.5 || y - A z ||_2^2.
* Solution is (A^H A + (1/mu) I)z = A^H y + (1/mu)(x_plus_u)
*
* @param prox_data should be of type prox_normaleq_data
* @param mu proximal penalty
* @param z output
* @param x_plus_u input
*/
static void prox_normaleq_fun(const operator_data_t* prox_data, float mu, float* z, const float* x_plus_u)
{
struct prox_normaleq_data* pdata = CAST_DOWN(prox_normaleq_data, prox_data);
if (0 == mu) {
md_copy(1, MD_DIMS(pdata->size), z, x_plus_u, FL_SIZE);
} else {
float rho = 1. / mu;
float* b = md_alloc_sameplace(1, MD_DIMS(pdata->size), FL_SIZE, x_plus_u);
md_copy(1, MD_DIMS(pdata->size), b, pdata->adj, FL_SIZE);
md_axpy(1, MD_DIMS(pdata->size), b, rho, x_plus_u);
if (NULL == pdata->op->norm_inv) {
struct iter_conjgrad_conf* cg_conf = pdata->cgconf;
cg_conf->l2lambda = rho;
iter_conjgrad(CAST_UP(cg_conf), pdata->op->normal, NULL, pdata->size, z, (float*)b, NULL);
} else {
linop_norm_inv_unchecked(pdata->op, rho, (complex float*)z, (const complex float*)b);
}
md_free(b);
}
}
/**
* Wrapper for calling pseudo-inverse operation using italgos.
*/
extern void linop_norm_inv_iter(void* _o, float lambda, float* _dst, const float* _src)
{
struct linop_s* o = _o;
complex float* dst = (complex float*)_dst;
const complex float* src = (complex float*)_src;
linop_norm_inv_unchecked(o, lambda, dst, src);
}
void fd_proj_noninc(const struct linop_s* o, complex float* optr, const complex float* iptr)
{
struct fdiff_s* data = (struct fdiff_s*)linop_get_data(o); // FIXME: CAST?
dump_cfl("impre", data->D, data->dims, iptr);
complex float* tmp2 = md_alloc_sameplace(data->D, data->dims, CFL_SIZE, optr);
linop_forward_unchecked(o, tmp2, iptr);
long tmpdim = data->dims[0];
long dims2[data->D];
md_select_dims(data->D, ~0u, dims2, data->dims);
dims2[0] *= 2;
dump_cfl("dxpre", data->D, data->dims, tmp2);
md_smin(data->D, dims2, (float*)optr, (float*)tmp2, 0.);
// add back initial value
dims2[0] = tmpdim;
for (unsigned int i = 0; i < data->D; i++) {
if (MD_IS_SET(data->flags, i)) {
dims2[i] = 1;
md_copy2(data->D, dims2, data->str, optr, data->str, tmp2, CFL_SIZE);
break;
}
}
dump_cfl("dxpost", data->D, data->dims, optr);
linop_norm_inv_unchecked(o, 0., optr, optr);
dump_cfl("impost", data->D, data->dims, optr);
md_free(tmp2);
}
