hod code cleaned out

c_tools/hod/transfnc.c

@@ -0,0 +1,70 @@
+/* PROGRAM TRANSFERFUNCTION
+
+   --- transfnc(xk)
+   --- compute the transfer function T(k) of the power spectrum
+   --- T(k) defined as P(k) = k^{xindx}*T^{2}(k)
+
+       * itrans=type of transfer function
+         0  -> no change (returns 1)
+         4  -> Efstathiou, Bond & White transfer function with Gamma as
+              specified (eqn. 7)
+	 5  -> Eisnstein & Hu     
+	 11 -> read in TF from file (usually CMBFAST)
+
+   NOTE: xk is in h/Mpc and is defined as k=2pi/lambda (not k=1/lambda)
+*/
+
+#include <stdio.h>
+#include <math.h>
+#include <stdlib.h>
+#include "header.h"
+
+/* EBW CDM parameters */
+
+#define aa  6.4
+#define bb  3.0
+#define cc  1.7
+#define xnu  1.13
+#define twopi  6.283185
+#define xnuinv  -0.884956
+
+double transfnc(double xk) 
+{
+  double transf;
+  double q,t1,t2;
+ 
+  if(xk==0.)
+    {
+      transf=1.;
+      return (double)transf;
+    }
+
+  switch(ITRANS)
+    {
+    case 0:
+      transf=1.;
+      break;
+      
+    case 4:
+      q = xk/GAMMA;
+      t1=aa*q+pow((bb*q),1.5)+(cc*q)*(cc*q);
+      t2=pow(t1,xnu);
+      transf=pow((1.+t2),xnuinv);
+      break;
+
+    case 5:
+      transf = tf_eisenstein_hu(xk);
+      break;
+
+    case 11:
+      transf = transfunc_file(xk);
+      break;
+
+    default:
+      fprintf(stderr,"transfnc> Unrecognized transfer function %d \n",ITRANS);
+      exit(-1);
+      break;
+
+    }
+  return (double)transf;
+}