Changes in sasmodels/kernel_header.c [1e7b0db0:b00a646] in sasmodels

File:

• sasmodels/kernel_header.c (modified) (3 diffs)

sasmodels/kernel_header.c

@@ -148 +148 @@
 inline double sas_sinx_x(double x) { return x==0 ? 1.0 : sin(x)/x; }
 
+// To rotate from the canonical position to theta, phi, psi, first rotate by
+// psi about the major axis, oriented along z, which is a rotation in the
+// detector plane xy. Next rotate by theta about the y axis, aligning the major
+// axis in the xz plane. Finally, rotate by phi in the detector plane xy.
+// To compute the scattering, undo these rotations in reverse order:
+//     rotate in xy by -phi, rotate in xz by -theta, rotate in xy by -psi
+// The returned q is the length of the q vector and (xhat, yhat, zhat) is a unit
+// vector in the q direction.
+// To change between counterclockwise and clockwise rotation, change the
+// sign of phi and psi.
+
 #if 1
+//think cos(theta) should be sin(theta) in new coords, RKH 11Jan2017
 #define ORIENT_SYMMETRIC(qx, qy, theta, phi, q, sn, cn) do { \
     SINCOS(phi*M_PI_180, sn, cn); \
     q = sqrt(qx*qx + qy*qy); \
-    cn  = (q==0. ? 1.0 : (cn*qx + sn*qy)/q * cos(theta*M_PI_180));  \
+    cn  = (q==0. ? 1.0 : (cn*qx + sn*qy)/q * sin(theta*M_PI_180));  \
     sn = sqrt(1 - cn*cn); \
     } while (0)
@@ -165 +177 @@
 #endif
 
+#if 1
+#define ORIENT_ASYMMETRIC(qx, qy, theta, phi, psi, q, xhat, yhat, zhat) do { \
+    q = sqrt(qx*qx + qy*qy); \
+    const double qxhat = qx/q; \
+    const double qyhat = qy/q; \
+    double sin_theta, cos_theta; \
+    double sin_phi, cos_phi; \
+    double sin_psi, cos_psi; \
+    SINCOS(theta*M_PI_180, sin_theta, cos_theta); \
+    SINCOS(phi*M_PI_180, sin_phi, cos_phi); \
+    SINCOS(psi*M_PI_180, sin_psi, cos_psi); \
+    xhat = qxhat*(-sin_phi*sin_psi + cos_theta*cos_phi*cos_psi) \
+         + qyhat*( cos_phi*sin_psi + cos_theta*sin_phi*cos_psi); \
+    yhat = qxhat*(-sin_phi*cos_psi - cos_theta*cos_phi*sin_psi) \
+         + qyhat*( cos_phi*cos_psi - cos_theta*sin_phi*sin_psi); \
+    zhat = qxhat*(-sin_theta*cos_phi) \
+         + qyhat*(-sin_theta*sin_phi); \
+    } while (0)
+#else
+// SasView 3.x definition of orientation
 #define ORIENT_ASYMMETRIC(qx, qy, theta, phi, psi, q, cos_alpha, cos_mu, cos_nu) do { \
     q = sqrt(qx*qx + qy*qy); \
@@ -179 +211 @@
     cos_nu = (-cos_phi*sin_psi*sin_theta + sin_phi*cos_psi)*qxhat + sin_psi*cos_theta*qyhat; \
     } while (0)
+#endif