Expose Sparse Op's CSR matrix to Python (#74)

Author: msricher

pyci/include/pyci.h

@@ -672,6 +672,12 @@ struct SparseOp final {
     template<class WfnType>
     void py_update(const SQuantOp &, const WfnType &);
 
+    Array<double> py_data() const;
+
+    Array<long> py_indices() const;
+
+    Array<long> py_indptr() const;
+
 private:
     void sort_row(const long);
 

pyci/src/binding.cpp

@@ -1083,6 +1083,10 @@ n : int
 
 sparse_op.def("squeeze", &SparseOp::squeeze, "Free any unused memory allocated to this object.");
 
+sparse_op.def("data", &SparseOp::py_data, "Return CSR matrix data vector", py::keep_alive<0, 1>());
+sparse_op.def("indices", &SparseOp::py_indices, "Return CSR matrix indices vector", py::keep_alive<0, 1>());
+sparse_op.def("indptr", &SparseOp::py_indptr, "Return CSR matrix index pointer vector", py::keep_alive<0, 1>());
+
 /*
 Section: Free functions
 */

pyci/src/sparseop.cpp

@@ -115,7 +115,7 @@ void SparseOp::solve_ci(const long n, const double *coeffs, const long ncv, cons
                         const double tol, double *evals, double *evecs) const {
     if ((nrow > 1 && n >= nrow) || (nrow == 1 && n > 1)) {
         throw std::invalid_argument("cannot find >=n eigenpairs for sparse operator with n rows");
-    } else if (!symmetric) {
+    } else if (nrow != ncol) {
         throw pybind11::type_error("Can only solve sparse symmetric matrix operators");
     } else if (nrow == 1) {
         *evals = get_element(0, 0) + ecore;
@@ -501,4 +501,16 @@ void SparseOp::add_row(const SQuantOp &ham, const GenCIWfn &wfn, const long idet
     append<long>(indptr, indices.size());
 }
 
+Array<double> SparseOp::py_data() const {
+    return Array<double>(data.size(), &data[0]);
+}
+
+Array<long> SparseOp::py_indices() const {
+    return Array<long>(indices.size(), &indices[0]);
+}
+
+Array<long> SparseOp::py_indptr() const {
+    return Array<long>(indptr.size(), &indptr[0]);
+}
+
 } // namespace pyci