hod code cleaned out

c_tools/hod/transfunc_file.c

@@ -0,0 +1,59 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include "header.h"
+
+/* This routine reads in a transfer function from a file. 
+ * - col 1 = k [h/Mpc]
+ * - col 2 = T(k)
+ * other columns not used.
+ *
+ * The TF is considered to be un-normalized, and will normalize all values 
+ * by the entry in the first line.
+ *
+ * The TF is stored in arrays an spline interpolation is used at all k values.
+ * The interpolation is in log(k)/log(TF) to preserve the power-law dependence
+ * of T(k) on k outside the k-range of the file.
+ */
+
+double transfunc_file(double xk)
+{
+  static double *x,*y,*y2;
+  static int flag=1,n;
+  int i;
+  double t,x0;
+  FILE *fp;
+  char a[1000];
+  float x1,x2;
+
+  if(flag)
+    {
+      flag=0;
+
+      fp=openfile(Files.TF_file);
+      n=filesize(fp);
+
+      x=dvector(1,n);
+      y=dvector(1,n);
+      y2=dvector(1,n);
+      for(i=1;i<=n;++i)
+	{
+	  fscanf(fp,"%f %f",&x1,&x2);
+	  x[i]=x1;
+	  y[i]=x2;
+	  if(i==1)x0=y[i];
+	  fgets(a,1000,fp);
+	  y[i]/=x0;
+	  x[i]=log(x[i]);
+	  y[i]=log(y[i]);
+	}
+      fclose(fp);
+      spline(x,y,n,1.0E+30,1.0E+30,y2);
+    }
+  xk=log(xk);
+  splint(x,y,y2,n,xk,&t);
+  return(exp(t));
+
+}
+
+