Made τ₀ = 0 possible

1 files changed, 5 insertions, 1 deletions

diff --git a/fourier_integrator.cpp b/fourier_integrator.cpp
index 69c8b03..4f4eff5 100644
--- a/fourier_integrator.cpp
+++ b/fourier_integrator.cpp
@@ -84,7 +84,11 @@ int main(int argc, char* argv[]) {
     // start from the exact solution for τ₀ = 0
     for (unsigned i = 0; i < n; i++) {
       Real τ = i * Δτ * M_PI;
-      C[i] = Γ₀ / 2 * (exp(-z * τ) - z * τ₀ * exp(-τ / τ₀)) / (z - pow(z, 3) * pow(τ₀, 2));
+      if (τ₀ > 0) {
+        C[i] = Γ₀ / 2 * (exp(-z * τ) - z * τ₀ * exp(-τ / τ₀)) / (z - pow(z, 3) * pow(τ₀, 2));
+      } else {
+        C[i] = Γ₀ / 2 * exp(-z * τ) / z;
+      }
       if (i > 0) {
         C[2 * n - i] = C[i];
       }