diff --git a/src/diffusion.cpp b/src/diffusion.cpp
index cda6f4b..52c71e0 100644
--- a/src/diffusion.cpp
+++ b/src/diffusion.cpp
@@ -13,6 +13,7 @@
 #include <Eigen/src/SparseLU/SparseLU.h>
 #include <Eigen/src/SparseQR/SparseQR.h>
 #include <iostream>
+#include <ostream>
 
 void BTCS2D(int x, int y, std::vector<double> &c, std::vector<double> &alpha,
             double timestep) {
@@ -34,7 +35,10 @@ void BTCS2D(int x, int y, std::vector<double> &c, std::vector<double> &alpha,
       double sx = (alpha[i * x + j] * timestep) / (dx * dx);
       double sy = (alpha[i * x + j] * timestep) / (dy * dy);
 
-      tripletList.push_back(T(A_line, i * x + j, (1 + 2 * sx + 2 * sy)));
+      tripletList.push_back(T(A_line, i * x + j, (1. + 2. * sx + 2. * sy)));
+
+      std::cout << sx << std::endl;
+
       tripletList.push_back(T(A_line, (i - 1) * x + j, sy));
       tripletList.push_back(T(A_line, (i + 1) * x + j, sy));
       tripletList.push_back(T(A_line, i * x + (j + 1), sx));
@@ -47,7 +51,7 @@ void BTCS2D(int x, int y, std::vector<double> &c, std::vector<double> &alpha,
 
   std::cout << b << std::endl;
 
-  Eigen::SparseMatrix<double> A(size, (x * y) - 4);
+  Eigen::SparseMatrix<double> A(size, x*y);
   A.setFromTriplets(tripletList.begin(), tripletList.end());
 
   Eigen::SparseQR<Eigen::SparseMatrix<double>, Eigen::COLAMDOrdering<int>>
diff --git a/src/main.cpp b/src/main.cpp
index 8269d9b..be66bcc 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -7,16 +7,16 @@ using namespace std;
 
 int main(int argc, char *argv[]) {
 
-  int x = 5;
-  int y = 5;
+  int x = 4;
+  int y = 4;
 
-  std::vector<double> alpha(x * y, -1.5 * pow(10, -2));
-  std::vector<double> input(x * y, 0);
-  input[x + 1] = 5.55 * std::pow(10, -6);
-  input[x + 2] = 5.5556554 * std::pow(10, -6);
-  input[x + 3] = 5.234564213 * std::pow(10, -6);
+  std::vector<double> alpha(x * y, 1 * pow(10, -9));
+  std::vector<double> input(x * y, 1 * std::pow(10,-6));
+  input[x + 1] = 5 * std::pow(10, -6);
+  // input[x + 2] = 5.5556554 * std::pow(10, -6);
+  // input[x + 3] = 5.234564213 * std::pow(10, -6);
 
-  BTCS2D(x, y, input, alpha, 10.);
+  BTCS2D(x, y, input, alpha, 1.);
 
   return 0;
 }