static (double, double) RankOneUpdate(smat_t R, long j, double[] u, double lambda, double vj, long do_nmf)
{
double g = 0, h = lambda;
if (R.col_ptr[j + 1] == R.col_ptr[j])
{
return(0, 0);
}
for (long idx = R.col_ptr[j]; idx < R.col_ptr[j + 1]; ++idx)
{
long i = R.row_idx[idx];
g += u[i] * R.val[idx];
h += u[i] * u[i];
}
double newvj = g / h, delta = 0, fundec = 0;
if (do_nmf > 0 & newvj < 0)
{
newvj = 0;
fundec = -2 * g * vj;
}
else
{
delta = vj - newvj;
fundec = h * delta * delta;
}
return(newvj, fundec);
}
public static smat_t load(string dataFolderName, string metaFileName, smat_t R, bool with_weights)
{
var metaInfo = File.ReadAllLines(Path.Combine(dataFolderName, metaFileName));
var rowsAndColumnsData = metaInfo[0].Split(' ');
var(rowsCount, columnsCount) = (long.Parse(rowsAndColumnsData[0]), long.Parse(rowsAndColumnsData[1]));
var trainingSetData = metaInfo[1].Split(' ');
var(nonZeroNumbersCount, trainingFileName) = (long.Parse(trainingSetData[0]), trainingSetData[1]);
R.load(rowsCount, columnsCount, nonZeroNumbersCount, Path.Combine(dataFolderName, trainingFileName),
with_weights);
return(R);
}
static double UpdateRating(smat_t R, double[] Wt2, double[] Ht2)
{
double loss = 0;
//#pragma omp parallel for schedule(kind) reduction(+:loss)
for (long c = 0; c < R.cols; ++c)
{
double Htc = Ht2[2 * c], oldHtc = Ht2[2 * c + 1], loss_inner = 0;
for (long idx = R.col_ptr[c]; idx < R.col_ptr[c + 1]; ++idx)
{
R.val[idx] -= Wt2[2 * R.row_idx[idx]] * Htc - Wt2[2 * R.row_idx[idx] + 1] * oldHtc;
loss_inner += R.val[idx] * R.val[idx];
}
loss += loss_inner;
}
return(loss);
}
static double UpdateRating(smat_t R, double[] Wt, double[] Ht, bool add)
{
double loss = 0;
var result = new ThreadSafe();
if (add)
{
Parallel.For(0, R.cols, () => 0d, (c, y, innerLoss) =>
{
double Htc = Ht[c];
for (long idx = R.col_ptr[c]; idx < R.col_ptr[c + 1]; ++idx)
{
R.val[idx] += Wt[R.row_idx[idx]] * Htc;
innerLoss += (R.with_weights ? R.weight[idx] : 1.0) * R.val[idx] * R.val[idx];
}
return(innerLoss);
},
innerLoss => { result.AddToTotal(innerLoss); });
return(result.Total);
}
Parallel.For(0, R.cols, () => 0d, (c, y, innerLoss) =>
{
double Htc = Ht[c];
for (long idx = R.col_ptr[c]; idx < R.col_ptr[c + 1]; ++idx)
{
R.val[idx] -= Wt[R.row_idx[idx]] * Htc;
innerLoss += (R.with_weights ? R.weight[idx] : 1.0) * R.val[idx] * R.val[idx];
}
return(innerLoss);
},
innerLoss => { result.AddToTotal(innerLoss); });
return(result.Total);
}
// Cyclic Coordinate Descent for Matrix Factorization
public static void ccdr1(smat_t R, double[][] W, double[][] H, parameter param)
{
long k = param.k;
long maxiter = param.maxiter;
long inneriter = param.maxinneriter;
// long num_threads_old = omp_get_num_threads();
double lambda = param.lambda;
double eps = param.eps;
double Itime = 0, Wtime = 0, Htime = 0, Rtime = 0, start = 0, oldobj = 0;
long num_updates = 0;
double reg = 0, loss;
// omp_set_num_threads(param.threads);
// Create transpose view of R
smat_t Rt = R.transpose();
var stopwatch = new Stopwatch();
// initial value of the regularization term
// H is a zero matrix now.
for (long t = 0; t < k; ++t)
{
for (long c = 0; c < R.cols; ++c)
{
H[t][c] = 0;
}
}
for (long t = 0; t < k; ++t)
{
for (long r = 0; r < R.rows; ++r)
{
reg += W[t][r] * W[t][r] * R.nnz_of_row(r);
}
}
Console.WriteLine("kek {0}", reg);
var oldWt = new double[R.rows];
var oldHt = new double[R.cols];
var u = new double[R.rows];
var v = new double[R.cols];
for (long oiter = 1; oiter <= maxiter; ++oiter)
{
double gnorm = 0, initgnorm = 0;
double rankfundec = 0;
double fundec_max = 0;
long early_stop = 0;
for (long tt = 0; tt < k; ++tt)
{
long t = tt;
if (early_stop >= 5)
{
break;
}
//if(oiter>1) { t = rand()%k; }
stopwatch.Start();
double[] Wt = W[t], Ht = H[t];
for (int i = 0; i < R.rows; i++)
{
oldWt[i] = u[i] = Wt[i];
}
for (int i = 0; i < R.cols; i++)
{
v[i] = Ht[i];
oldHt[i] = (oiter == 1) ? 0 : v[i];
}
// Create Rhat = R - Wt Ht^T
if (oiter > 1)
{
UpdateRating(R, Wt, Ht, true);
UpdateRating(Rt, Ht, Wt, true);
}
stopwatch.Stop();
Itime += stopwatch.ElapsedMilliseconds;
gnorm = 0;
initgnorm = 0;
double innerfundec_max = 0;
long maxit = inneriter;
// if(oiter > 1) maxit *= 2;
for (long iter = 1; iter <= maxit; ++iter)
{
// Update H[t]
stopwatch.Restart();
gnorm = 0;
var innerFunDecCur = 0d;
for (long c = 0; c < R.cols; ++c)
{
var(newV, innerfundec) = RankOneUpdate(R, c, u, lambda * (R.col_ptr[c + 1] - R.col_ptr[c]),
v[c], param.do_nmf);
innerFunDecCur += innerfundec;
v[c] = newV;
}
num_updates += R.cols;
stopwatch.Stop();
Htime += stopwatch.ElapsedMilliseconds;
// Update W[t]
stopwatch.Restart();
for (long c = 0; c < Rt.cols; ++c)
{
var(newU, innerfundec) = RankOneUpdate(Rt, c, v,
lambda * (Rt.col_ptr[c + 1] - Rt.col_ptr[c]), u[c], param.do_nmf);
u[c] = newU;
innerFunDecCur += innerfundec;
}
num_updates += Rt.cols;
if ((innerFunDecCur < fundec_max * eps))
{
if (iter == 1)
{
early_stop += 1;
}
break;
}
rankfundec += innerFunDecCur;
innerfundec_max = Math.Max(innerfundec_max, innerFunDecCur);
// the fundec of the first inner iter of the first rank of the first outer iteration could be too large!!
if (!(oiter == 1 && t == 0 && iter == 1))
{
fundec_max = Math.Max(fundec_max, innerFunDecCur);
}
stopwatch.Stop();
Wtime += stopwatch.ElapsedMilliseconds;
}
// Update R and Rt
// start = omp_get_wtime();
stopwatch.Restart();
for (int i = 0; i < R.rows; i++)
{
Wt[i] = u[i];
}
for (int i = 0; i < R.cols; i++)
{
Ht[i] = v[i];
}
loss = UpdateRating(R, u, v, false);
loss = UpdateRating(Rt, v, u, false);
stopwatch.Stop();
Rtime += stopwatch.ElapsedMilliseconds;
for (long c = 0; c < R.cols; ++c)
{
reg += R.nnz_of_col(c) * Ht[c] * Ht[c];
reg -= R.nnz_of_col(c) * oldHt[c] * oldHt[c];
}
for (long c = 0; c < Rt.cols; ++c)
{
reg += Rt.nnz_of_col(c) * (Wt[c] * Wt[c]);
reg -= Rt.nnz_of_col(c) * (oldWt[c] * oldWt[c]);
}
double obj = loss + reg * lambda;
Console.WriteLine("iter {0} rank {1} time {2} loss {3} obj {4} diff {5} gnorm {6} reg {7} ",
oiter, t + 1, Htime + Wtime + Rtime, loss, obj, oldobj - obj, initgnorm, reg);
oldobj = obj;
}
}
}
