private static SVDRec svdLAS2(SMat A)
{
int ibeta, it, irnd, machep, negep, n, steps, nsig, neig;
double kappa = 1e-6;
double[] las2end = new double[2] { -1.0e-30, 1.0e-30 };
double[] ritz, bnd;
double[][] wptr = new double[10][];
svdResetCounters();
int dimensions = A.rows;
if (A.cols < dimensions) dimensions = A.cols;
int iterations = dimensions;
// Check parameters
if (check_parameters(A, dimensions, iterations, las2end[0], las2end[1]) > 0) return null;
// If A is wide, the SVD is computed on its transpose for speed.
bool transpose = false;
if (A.cols >= A.rows * 1.2)
{
//Console.WriteLine("TRANSPOSING THE MATRIX FOR SPEED\n");
transpose = true;
A = svdTransposeS(A);
}
n = A.cols;
// Compute machine precision
ibeta = it = irnd = machep = negep = 0;
machar(ref ibeta, ref it, ref irnd, ref machep, ref negep);
eps1 = eps * Math.Sqrt((double)n);
reps = Math.Sqrt(eps);
eps34 = reps * Math.Sqrt(reps);
//Console.WriteLine("Machine precision {0} {1} {2} {3} {4}", ibeta, it, irnd, machep, negep);
// Allocate temporary space.
wptr[0] = new double[n];
for (int i = 0; i < n; ++i) wptr[0][i] = 0.0;
wptr[1] = new double[n];
wptr[2] = new double[n];
wptr[3] = new double[n];
wptr[4] = new double[n];
wptr[5] = new double[n];
wptr[6] = new double[iterations];
wptr[7] = new double[iterations];
wptr[8] = new double[iterations];
wptr[9] = new double[iterations + 1];
ritz = new double[iterations + 1];
for (int i = 0; i < iterations + 1; ++i) ritz[0] = 0.0;
bnd = new double[iterations + 1];
for (int i = 0; i < iterations + 1; ++i) bnd[0] = 0.0;
LanStore = new double[iterations + MAXLL][];
for (int i = 0; i < iterations + MAXLL; ++i)
{
LanStore[i] = null;
}
OPBTemp = new double[A.rows];
// Actually run the lanczos thing:
neig = 0;
steps = lanso(A, iterations, dimensions, las2end[0], las2end[1], ritz, bnd, wptr, ref neig, n);
//Console.WriteLine("NUMBER OF LANCZOS STEPS {0}", steps + 1);
//Console.WriteLine("RITZ VALUES STABILIZED = RANK {0}", neig);
kappa = svd_dmax(Math.Abs(kappa), eps34);
SVDRec R = new SVDRec();
R.d = dimensions;
DMat Tmp1 = new DMat();
Tmp1.rows = R.d;
Tmp1.cols = A.rows;
Tmp1.value = new double[Tmp1.rows][];
for (int mm = 0; mm < Tmp1.rows; ++mm)
{
Tmp1.value[mm] = new double[Tmp1.cols];
for (int j = 0; j < Tmp1.cols; ++j)
{
Tmp1.value[mm][j] = 0.0;
}
}
R.Ut = Tmp1;
R.S = new double[R.d];
for (int k = 0; k < R.d; ++k)
{
R.S[k] = 0.0;
}
DMat Tmp2 = new DMat();
Tmp2.rows = R.d;
Tmp2.cols = A.cols;
Tmp2.value = new double[Tmp2.rows][];
for (int mm = 0; mm < Tmp2.rows; ++mm)
{
Tmp2.value[mm] = new double[Tmp2.cols];
for (int j = 0; j < Tmp2.cols; ++j)
{
Tmp2.value[mm][j] = 0.0;
}
}
R.Vt = Tmp2;
nsig = ritvec(n, A, R, kappa, ritz, bnd, wptr[6], wptr[9], wptr[5], steps, neig);
// This swaps and transposes the singular matrices if A was transposed.
if (transpose)
{
DMat T;
T = R.Ut;
R.Ut = R.Vt;
R.Vt = T;
}
return R;
}
private static double startv(SMat A, double[][] wptr, int step, int n)
{
double rnm2, t;
double[] r;
int irand = 0, id, i;
rnm2 = svd_ddot(n, wptr[0], 1, wptr[0], 1);
irand = 918273 + step;
r = wptr[0];
for (id = 0; id < 3; id++)
{
if (id > 0 || step > 0 || rnm2 == 0)
{
for (i = 0; i < n; i++)
{
r[i] = svd_random2(ref irand);
}
}
svd_dcopy(n, wptr[0], 0, 1, wptr[3], 0, 1);
svd_opb(A, wptr[3], wptr[0], OPBTemp);
svd_dcopy(n, wptr[0], 0, 1, wptr[3], 0, 1);
rnm2 = svd_ddot(n, wptr[0], 1, wptr[3], 1);
if (rnm2 > 0.0) break;
}
// fatal error
if (rnm2 <= 0.0)
{
ierr = 8192;
return (-1);
}
if (step > 0)
{
for (i = 0; i < step; i++)
{
store(n, (int)storeVals.RETRQ, i, wptr[5]);
t = -svd_ddot(n, wptr[3], 1, wptr[5], 1);
svd_daxpy(n, t, wptr[5], 1, wptr[0], 1);
}
t = svd_ddot(n, wptr[4], 1, wptr[0], 1);
svd_daxpy(n, -t, wptr[2], 1, wptr[0], 1);
svd_dcopy(n, wptr[0], 0, 1, wptr[3], 0, 1);
t = svd_ddot(n, wptr[3], 1, wptr[0], 1);
if (t <= eps * rnm2) t = 0.0;
rnm2 = t;
}
return Math.Sqrt(rnm2);
}
private static void stpone(SMat A, double[][] wrkptr, ref double rnmp, ref double tolp, int n)
{
double t, rnm, anorm;
double[] alf;
alf = wrkptr[6];
rnm = startv(A, wrkptr, 0, n);
if (rnm == 0.0 || ierr != 0) return;
t = 1.0 / rnm;
svd_datx(n, t, wrkptr[0], 1, wrkptr[1], 1);
svd_dscal(n, t, wrkptr[3], 1);
svd_opb(A, wrkptr[3], wrkptr[0], OPBTemp);
alf[0] = svd_ddot(n, wrkptr[0], 1, wrkptr[3], 1);
svd_daxpy(n, -alf[0], wrkptr[1], 1, wrkptr[0], 1);
t = svd_ddot(n, wrkptr[0], 1, wrkptr[3], 1);
svd_daxpy(n, -t, wrkptr[1], 1, wrkptr[0], 1);
alf[0] += t;
svd_dcopy(n, wrkptr[0], 0, 1, wrkptr[4], 0, 1);
rnm = Math.Sqrt(svd_ddot(n, wrkptr[0], 1, wrkptr[4], 1));
anorm = rnm + Math.Abs(alf[0]);
rnmp = rnm;
tolp = reps * anorm;
}
private static int lanso(SMat A, int iterations, int dimensions, double endl, double endr,
double[] ritz, double[] bnd, double[][] wptr, ref int neigp, int n)
{
double[] alf, eta, oldeta, bet, wrk;
double rnm, tol;
int ll, first, last, id2, id3, i, l, neig = 0, j = 0, intro = 0;
alf = wptr[6];
eta = wptr[7];
oldeta = wptr[8];
bet = wptr[9];
wrk = wptr[5];
rnm = 0.0;
tol = 0.0;
stpone(A, wptr, ref rnm, ref tol, n);
if (rnm == 0.0 || ierr != 0) return 0;
eta[0] = eps1;
oldeta[0] = eps1;
ll = 0;
first = 1;
last = svd_imin(dimensions + svd_imax(8, dimensions), iterations);
int ENOUGH = 0;
while (ENOUGH == 0)
{
if (rnm <= tol) rnm = 0.0;
j = lanczos_step(A, first, last, wptr, alf, eta, oldeta, bet, ref ll, ref ENOUGH, ref rnm, ref tol, n);
if (ENOUGH > 0) j = j - 1;
else j = last - 1;
first = j + 1;
bet[j + 1] = rnm;
l = 0;
for (id2 = 0; id2 < j; id2++)
{
if (l > j) break;
for (i = l; i <= j; i++) if (bet[i + 1] == 0.0) break;
if (i > j) i = j;
svd_dcopy(i - l + 1, alf, l, 1, ritz, l, -1);
svd_dcopy(i - l, bet, l + 1, 1, wrk, l + 1, -1);
imtqlb(i - l + 1, ritz, wrk, bnd);
if (ierr != 0)
{
Console.WriteLine("svdLAS2: imtqlb failed to converge {0}", ierr);
}
for (id3 = l; id3 <= i; id3++)
{
bnd[id3] = rnm * Math.Abs(bnd[id3]);
}
l = i + 1;
}
svd_dsort2((j + 1) / 2, j + 1, ritz, bnd);
neig = error_bound(ref ENOUGH, endl, endr, ritz, bnd, j, tol);
neigp = neig;
if (neig < dimensions)
{
if (neig == 0)
{
last = first + 9;
intro = first;
}
else
{
last = first + svd_imax(3, 1 + ((j - intro) * (dimensions - neig)) / neig);
}
last = svd_imin(last, iterations);
}
else
{
ENOUGH = 1;
}
int RES = 0;
if (first >= iterations) RES = 1;
ENOUGH = ENOUGH | RES;
}
store(n, (int)(storeVals.STORQ), j, wptr[1]);
return j;
}
private static int ritvec(int n, SMat A, SVDRec R, double kappa, double[] ritz, double[] bnd,
double[] alf, double[] bet, double[] w2, int steps, int neig)
{
int js, jsq, i, k, id2, tmp, nsig = 0, x;
double tmp0, tmp1, xnorm;
double[] s;
double[] xv2;
double[] w1 = R.Vt.value[0];
js = steps + 1;
jsq = js * js;
s = new double[jsq];
for (k = 0; k < jsq; ++k) s[k] = 0.0;
xv2 = new double[n];
for (i = 0; i < jsq; i += (js + 1)) s[i] = 1.0;
svd_dcopy(js, alf, 0, 1, w1, 0, -1);
svd_dcopy(steps, bet, 1, 1, w2, 1, -1);
imtql2(js, js, w1, w2, s);
if (ierr != 0) return 0;
nsig = 0;
x = 0;
id2 = jsq - js;
for (k = 0; k < js; k++)
{
tmp = id2;
if (bnd[k] <= kappa * Math.Abs(ritz[k]) && k > js - neig - 1)
{
if (--x < 0) x = R.d - 1;
w1 = R.Vt.value[x];
for (i = 0; i < n; i++) w1[i] = 0.0;
for (i = 0; i < js; i++)
{
store(n, (int)(storeVals.RETRQ), i, w2);
svd_daxpy(n, s[tmp], w2, 1, w1, 1);
tmp -= js;
}
nsig++;
}
id2++;
}
// x is now the location of the highest singular value.
rotateArray(R, x);
R.d = svd_imin(R.d, nsig);
for (x = 0; x < R.d; x++)
{
svd_opb(A, R.Vt.value[x], xv2, OPBTemp);
tmp0 = svd_ddot(n, R.Vt.value[x], 1, xv2, 1);
svd_daxpy(n, -tmp0, R.Vt.value[x], 1, xv2, 1);
tmp0 = Math.Sqrt(tmp0);
xnorm = Math.Sqrt(svd_ddot(n, xv2, 1, xv2, 1));
svd_opa(A, R.Vt.value[x], R.Ut.value[x]);
tmp1 = 1.0 / tmp0;
svd_dscal(A.rows, tmp1, R.Ut.value[x], 1);
xnorm *= tmp1;
bnd[i] = xnorm;
R.S[x] = tmp0;
}
return nsig;
}
private static void svd_opb(SMat A, double[] x, double[] y, double[] temp)
{
int i, j, end;
int[] pointr = A.pointr;
int[] rowind = A.rowind;
double[] value = A.value;
int n = A.cols;
SVDCount[(int)(svdCounters.SVD_MXV)] += 2;
for (i = 0; i < n; ++i) y[i] = 0.0;
for (i = 0; i < A.rows; i++) temp[i] = 0.0;
for (i = 0; i < A.cols; i++)
{
end = pointr[i + 1];
for (j = pointr[i]; j < end; j++)
{
temp[rowind[j]] += value[j] * x[i];
}
}
for (i = 0; i < A.cols; i++)
{
end = pointr[i + 1];
for (j = pointr[i]; j < end; j++)
{
y[i] += value[j] * temp[rowind[j]];
}
}
}
private static int lanczos_step(SMat A, int first, int last, double[][] wptr, double[] alf, double[] eta,
double[] oldeta, double[] bet, ref int ll, ref int enough, ref double rnmp, ref double tolp, int n)
{
double t, anorm;
double[] mid;
double rnm = rnmp;
double tol = tolp;
int i, j;
for (j = first; j < last; j++)
{
mid = wptr[2];
wptr[2] = wptr[1];
wptr[1] = mid;
mid = wptr[3];
wptr[3] = wptr[4];
wptr[4] = mid;
store(n, (int)(storeVals.STORQ), j - 1, wptr[2]);
if (j - 1 < MAXLL) store(n, (int)(storeVals.STORP), j - 1, wptr[4]);
bet[j] = rnm;
if (bet[j] == 0.0)
{
rnm = startv(A, wptr, j, n);
if (rnm < 0.0)
{
Console.WriteLine("Fatal error: {0}", ierr);
Environment.Exit(1);
}
if (ierr != 0) return j;
if (rnm == 0.0) enough = 1;
}
if (enough == 1)
{
mid = wptr[2];
wptr[2] = wptr[1];
wptr[1] = mid;
break;
}
t = 1.0 / rnm;
svd_datx(n, t, wptr[0], 1, wptr[1], 1);
svd_dscal(n, t, wptr[3], 1);
svd_opb(A, wptr[3], wptr[0], OPBTemp);
svd_daxpy(n, -rnm, wptr[2], 1, wptr[0], 1);
alf[j] = svd_ddot(n, wptr[0], 1, wptr[3], 1);
svd_daxpy(n, -alf[j], wptr[1], 1, wptr[0], 1);
if (j <= MAXLL && (Math.Abs(alf[j - 1]) > 4.0 * Math.Abs(alf[j])))
{
ll = j;
}
for (i = 0; i < svd_imin(ll, j - 1); i++)
{
store(n, (int)(storeVals.RETRP), i, wptr[5]);
t = svd_ddot(n, wptr[5], 1, wptr[0], 1);
store(n, (int)(storeVals.RETRQ), i, wptr[5]);
svd_daxpy(n, -t, wptr[5], 1, wptr[0], 1);
eta[i] = eps1;
oldeta[i] = eps1;
}
t = svd_ddot(n, wptr[0], 1, wptr[4], 1);
svd_daxpy(n, -t, wptr[2], 1, wptr[0], 1);
if (bet[j] > 0.0) bet[j] = bet[j] + t;
t = svd_ddot(n, wptr[0], 1, wptr[3], 1);
svd_daxpy(n, -t, wptr[1], 1, wptr[0], 1);
alf[j] = alf[j] + t;
svd_dcopy(n, wptr[0], 0, 1, wptr[4], 0, 1);
rnm = Math.Sqrt(svd_ddot(n, wptr[0], 1, wptr[4], 1));
anorm = bet[j] + Math.Abs(alf[j]) + rnm;
tol = reps * anorm;
ortbnd(alf, eta, oldeta, bet, j, rnm);
purge(n, ll, wptr[0], wptr[1], wptr[4], wptr[3], wptr[5], eta, oldeta, j, rnmp, tol);
if (rnm <= tol) rnm = 0.0;
}
rnmp = rnm;
tolp = tol;
return j;
}
private static void svd_opa(SMat A, double[] x, double[] y)
{
int end, i, j;
int[] pointr = A.pointr;
int[] rowind = A.rowind;
double[] value = A.value;
SVDCount[(int)(svdCounters.SVD_MXV)]++;
for (int k = 0; k < A.rows; ++k)
{
y[k] = 0.0;
}
for (i = 0; i < A.cols; i++)
{
end = pointr[i + 1];
for (j = pointr[i]; j < end; j++)
{
y[rowind[j]] += value[j] * x[i];
}
}
}
private static int check_parameters(SMat A, int dimensions, int iterations, double endl, double endr)
{
int error_index;
error_index = 0;
if (endl > endr) error_index = 2;
else if (dimensions > iterations) error_index = 3;
else if (A.cols <= 0 || A.rows <= 0) error_index = 4;
else if (iterations <= 0 || iterations > A.cols || iterations > A.rows) error_index = 5;
else if (dimensions <= 0 || dimensions > iterations) error_index = 6;
if (error_index > 0) Console.WriteLine("svdLAS2 parameter error: %s\n");
return error_index;
}
private static SMat svdTransposeS(SMat S)
{
int r, c, i, j;
SMat N = svdNewSMat(S.cols, S.rows, S.vals);
for (i = 0; i < S.vals; i++) N.pointr[S.rowind[i]]++;
N.pointr[S.rows] = S.vals - N.pointr[S.rows - 1];
for (r = S.rows - 1; r > 0; r--) N.pointr[r] = N.pointr[r + 1] - N.pointr[r - 1];
N.pointr[0] = 0;
for (c = 0, i = 0; c < S.cols; c++)
{
for (; i < S.pointr[c + 1]; i++)
{
r = S.rowind[i];
j = N.pointr[r + 1]++;
N.rowind[j] = c;
N.value[j] = S.value[i];
}
}
return N;
}
private static SMat svdNewSMat(int rows, int cols, int vals)
{
SMat S = new SMat();
S.rows = rows;
S.cols = cols;
S.vals = vals;
S.pointr = new int[cols + 1];
S.rowind = new int[vals];
S.value = new double[vals];
return S;
}
// Functions for reading-writing data
private static SMat svdLoadSparseMatrix(string datafile)
{
try
{
SMat S = new SMat();
using (FileStream stream = new FileStream(datafile, FileMode.Open))
{
using (BinaryReader reader = new BinaryReader(stream))
{
S.rows = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
S.cols = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
S.vals = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
S.pointr = new int[S.cols + 1];
for (int k = 0; k < S.cols + 1; ++k) S.pointr[k] = 0;
S.rowind = new int[S.vals];
S.value = new double[S.vals];
for (int c = 0, v = 0; c < S.cols; c++)
{
int n = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
S.pointr[c] = v;
for (int i = 0; i < n; i++, v++)
{
int r = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
int nBuf = System.Net.IPAddress.NetworkToHostOrder(reader.ReadInt32());
byte[] b = BitConverter.GetBytes(nBuf);
float f = BitConverter.ToSingle(b, 0);
S.rowind[v] = r;
S.value[v] = f;
}
S.pointr[S.cols] = S.vals;
}
reader.Close();
}
stream.Close();
}
return S;
}
catch (Exception e)
{
Console.WriteLine(e.Message);
return null;
}
}
