initial import

libsharp/ylmgen_c.h

@@ -0,0 +1,92 @@
+/*
+ *  This file is part of libsharp.
+ *
+ *  libsharp is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  libsharp is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with libsharp; if not, write to the Free Software
+ *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ */
+
+/*
+ *  libsharp is being developed at the Max-Planck-Institut fuer Astrophysik
+ *  and financially supported by the Deutsches Zentrum fuer Luft- und Raumfahrt
+ *  (DLR).
+ */
+
+/*! \file ylmgen_c.h
+ *  Code for efficient calculation of Y_lm(phi=0,theta)
+ *
+ *  Copyright (C) 2005-2012 Max-Planck-Society
+ *  \author Martin Reinecke
+ */
+
+#ifndef PLANCK_YLMGEN_C_H
+#define PLANCK_YLMGEN_C_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+enum { minscale=-8, limscale=-3, maxscale=5 };
+static const double fbig=0x1p+90,fsmall=0x1p-90;
+
+typedef struct { double f[2]; } ylmgen_dbl2;
+typedef struct { double f[3]; } ylmgen_dbl3;
+
+typedef struct
+  {
+/* for public use; immutable during lifetime */
+  int lmax, mmax, s;
+  double *cf;
+
+/* for public use; will typically change after call to Ylmgen_prepare() */
+  int m;
+
+/* used if s==0 */
+  double *mfac;
+  ylmgen_dbl2 *rf;
+
+/* used if s!=0 */
+  int sinPow, cosPow, preMinus_p, preMinus_m;
+  double *prefac;
+  int *fscale;
+  ylmgen_dbl3 *fx;
+
+/* internal usage only */
+/* used if s==0 */
+  double *root, *iroot;
+
+/* used if s!=0 */
+  double *flm1, *flm2, *inv;
+  int mlo, mhi;
+  } Ylmgen_C;
+
+/*! Creates a generator which will calculate helper data for Y_lm calculation
+    up to \a l=l_max and \a m=m_max. */
+void Ylmgen_init (Ylmgen_C *gen, int l_max, int m_max, int spin);
+
+/*! Deallocates a generator previously initialised by Ylmgen_init(). */
+void Ylmgen_destroy (Ylmgen_C *gen);
+
+/*! Prepares the object for the calculation at \a m. */
+void Ylmgen_prepare (Ylmgen_C *gen, int m);
+
+/*! Returns a pointer to an array with \a lmax+1 entries containing
+    normalisation factors that must be applied to Y_lm values computed for
+    \a spin. The array must be deallocated (using free()) by the user. */
+double *Ylmgen_get_norm (int lmax, int spin);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif