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