/*
* Generates a random directed binary graph with a Toeplitz organization.
*/
MATRIX_T* BCT_NAMESPACE::maketoeplitzCIJ(int N, int K, FP_T s) {
// profile = normpdf([1:N-1],0.5,s);
VECTOR_T* indices = sequence(1, N - 1);
VECTOR_T* profile = normpdf(indices, 0.5, s);
VECTOR_ID(free)(indices);
// template = toeplitz([0 profile],[0 profile]);
VECTOR_T* temp = concatenate(0.0, profile);
VECTOR_ID(free)(profile);
profile = temp;
MATRIX_T* _template = toeplitz(profile, profile);
VECTOR_ID(free)(profile);
// template = template.*(K./sum(sum(template)))
VECTOR_T* sum__template = sum(_template);
FP_T sum_sum__template = sum(sum__template);
VECTOR_ID(free)(sum__template);
MATRIX_ID(scale)(_template, (FP_T)K / sum_sum__template);
// CIJ = zeros(N);
MATRIX_T* CIJ = zeros(N);
// while ((sum(sum(CIJ)) ~= K))
VECTOR_T* sum_CIJ = sum(CIJ);
FP_T sum_sum_CIJ = sum(sum_CIJ);
VECTOR_ID(free)(sum_CIJ);
while ((int)sum_sum_CIJ != K) {
// CIJ = (rand(N)<template);
MATRIX_T* rand_N = rand(N);
MATRIX_ID(free)(CIJ);
CIJ = compare_elements(rand_N, fp_less, _template);
MATRIX_ID(free)(rand_N);
sum_CIJ = sum(CIJ);
sum_sum_CIJ = sum(sum_CIJ);
VECTOR_ID(free)(sum_CIJ);
}
MATRIX_ID(free)(_template);
return CIJ;
}
/**
* Return the coefficients for CONV operator. The coefficient matrix is
* constructed by creating a toeplitz matrix with the constant vector
* in DATA as the columns. Multiplication by this matrix is equivalent
* to convolution.
*
* Parameters: linOp LIN with type CONV. Data should should contain a
* column vector that the variables are convolved with.
*
* Returns: vector of coefficients for convolution linOp
*/
std::vector<Matrix> get_conv_mat(LinOp &lin) {
assert(lin.type == CONV);
Matrix constant = get_constant_data(lin, false);
int rows = lin.size[0];
int nonzeros = constant.rows();
int cols = lin.args[0]->size[0];
Matrix toeplitz(rows, cols);
std::vector<Triplet> tripletList;
tripletList.reserve(nonzeros * cols);
for (int col = 0; col < cols; col++) {
int row_start = col;
for ( int k = 0; k < constant.outerSize(); ++k ) {
for ( Matrix::InnerIterator it(constant, k); it; ++it ) {
int row_idx = row_start + it.row();
tripletList.push_back(Triplet(row_idx, col, it.value()));
}
}
}
toeplitz.setFromTriplets(tripletList.begin(), tripletList.end());
toeplitz.makeCompressed();
return build_vector(toeplitz);
}
