1 files changed, 59 insertions, 0 deletions
diff --git a/src/rotation.F90 b/src/rotation.F90
new file mode 100644
index 0000000..d76973e
--- /dev/null
+++ b/src/rotation.F90
@@ -0,0 +1,59 @@
+! $Header$
+
+#include "cctk.h"
+#include "cctk_Parameters.h"
+
+module rotation
+  use constants
+  implicit none
+  DECLARE_CCTK_PARAMETERS
+  private
+  
+  public make_euler
+  
+contains
+  
+  subroutine make_euler1 (phi, tt)
+    CCTK_REAL, intent(in)  :: phi
+    CCTK_REAL, intent(out) :: tt(0:3,0:3)
+    ! y^a = T^a_b x^b
+    tt = delta4
+    tt(1,1) =  cos(phi)
+    tt(1,2) = -sin(phi)
+    tt(2,1) =  sin(phi)
+    tt(2,2) =  cos(phi)
+  end subroutine make_euler1
+  
+  subroutine make_euler2 (theta, tt)
+    CCTK_REAL, intent(in)  :: theta
+    CCTK_REAL, intent(out) :: tt(0:3,0:3)
+    ! y^a = T^a_b x^b
+    tt = delta4
+    tt(2,2) =  cos(theta)
+    tt(2,3) = -sin(theta)
+    tt(3,2) =  sin(theta)
+    tt(3,3) =  cos(theta)
+  end subroutine make_euler2
+  
+  subroutine make_euler3 (psi, tt)
+    CCTK_REAL, intent(in)  :: psi
+    CCTK_REAL, intent(out) :: tt(0:3,0:3)
+    ! y^a = T^a_b x^b
+    tt = delta4
+    tt(1,1) =  cos(psi)
+    tt(1,2) = -sin(psi)
+    tt(2,1) =  sin(psi)
+    tt(2,2) =  cos(psi)
+  end subroutine make_euler3
+  
+  subroutine make_euler (phi, theta, psi, tt)
+    CCTK_REAL, intent(in)  :: phi, theta, psi
+    CCTK_REAL, intent(out) :: tt(0:3,0:3)
+    CCTK_REAL :: tt1(0:3,0:3), tt2(0:3,0:3), tt3(0:3,0:3)
+    call make_euler1 (phi, tt1)
+    call make_euler2 (theta, tt2)
+    call make_euler3 (psi, tt3)
+    tt = matmul(tt3, matmul(tt2, tt1))
+  end subroutine make_euler
+  
+end module rotation