fix eigen compilation issues

Author: taminob

mlir/lib/Dialect/MQTOpt/Transforms/GateDecompositionPattern.cpp

@@ -16,8 +16,7 @@
 #include <array>
 #include <cmath>
 #include <cstddef>
-#include <eigen3/unsupported/Eigen/CXX11/Tensor>
-#include <eigen3/unsupported/Eigen/MatrixFunctions>
+#include <format>
 #include <llvm/ADT/STLExtras.h>
 #include <mlir/IR/MLIRContext.h>
 #include <mlir/IR/Operation.h>
@@ -27,6 +26,7 @@
 #include <mlir/Support/LogicalResult.h>
 #include <numbers>
 #include <string>
+#include <unsupported/Eigen/MatrixFunctions>
 #include <utility>
 
 namespace mqt::ir::opt {
@@ -1024,7 +1024,7 @@ struct GateDecompositionPattern final
         auto tmp = remEuclid(x, qc::PI_2);
         return std::min(tmp, qc::PI_2 - tmp);
       });
-      std::array<int, cstemp.size()> order{
+      std::array<int, 3> order{
           0, 1, 2}; // TODO: needs to be adjusted depending on eigenvector
                     // order in eigen decomposition algorithm?
       llvm::stable_sort(order,

mlir/lib/Dialect/MQTOpt/Transforms/Helpers.h

@@ -14,9 +14,9 @@
 #include "mlir/Dialect/MQTOpt/IR/MQTOptDialect.h"
 
 #include <algorithm>
-#include <eigen3/Eigen/Core>
-#include <eigen3/Eigen/Eigenvalues>
-#include <eigen3/unsupported/Eigen/KroneckerProduct> // TODO: unstable
+#include <Eigen/Core>
+#include <Eigen/Eigenvalues>
+#include <unsupported/Eigen/KroneckerProduct> // TODO: unstable
 #include <iomanip>                                   // TODO: remove
 #include <iostream>                                  // TODO: remove
 #include <mlir/Dialect/Arith/IR/Arith.h>
@@ -207,10 +207,7 @@ getParameters(UnitaryInterface op) {
 template <typename T>
 inline Eigen::Matrix4<T> kroneckerProduct(const Eigen::Matrix2<T>& lhs,
                                           const Eigen::Matrix2<T>& rhs) {
-  Eigen::Matrix4<T> result;
-  Eigen::KroneckerProduct kroneckerProduct{lhs, rhs};
-  kroneckerProduct.evalTo(result);
-  return result;
+  return Eigen::kroneckerProduct(lhs, rhs);
 }
 
 template <typename T, int N, int M>