From cff1d2ee3c7730b672f239de5eb1aeb1a0bfd1db Mon Sep 17 00:00:00 2001
From: Ian Jauslin <jauslin@ias.edu>
Date: Fri, 12 Jan 2018 19:20:59 +0000
Subject: Simpler expression for fft term

---
 src/main.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'src/main.c')

diff --git a/src/main.c b/src/main.c
index 9420e90..b92698a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -77,10 +77,10 @@ int read_args(int argc, const char* argv[], ns_params* params, unsigned int* nst
   *nsteps=16777216;
   params->nu=4.9632717887631524e-05;
   */
-  params->h=1e-5;
   params->K=16;
+  params->h=1e-3/(2*params->K+1);
   *nsteps=10000000;
-  params->nu=1e-4;
+  params->nu=1./1024/(2*params->K+1);
 
   // loop over arguments
   for(i=1;i<argc;i++){
@@ -221,7 +221,7 @@ int enstrophy(ns_params params, unsigned int Nsteps){
     for(ky=-params.K;ky<=params.K;ky++){
       //params.g[KLOOKUP(kx,ky,params.S)]=sqrt(kx*kx*ky*ky)*exp(-(kx*kx+ky*ky));
       if((kx==2 && ky==-1) || (kx==-2 && ky==1)){
-	params.g[KLOOKUP(kx,ky,params.S)]=1;
+	params.g[KLOOKUP(kx,ky,params.S)]=1.0*params.K;
       }
       else{
 	params.g[KLOOKUP(kx,ky,params.S)]=0;
@@ -246,19 +246,21 @@ int enstrophy(ns_params params, unsigned int Nsteps){
     ins_step(u, params, fft_vects, tmp1, tmp2, tmp3);
     alpha=compute_alpha(u, params);
 
+    /*
     // to avoid errors building up in imaginary part
     for(kx=-params.K;kx<=params.K;kx++){
       for(ky=-params.K;ky<=params.K;ky++){
 	u[KLOOKUP(kx,ky,params.S)]=__real__ u[KLOOKUP(kx,ky,params.S)];
       }
     }
+    */
 
     // running average
     if(t>0){
       avg=avg-(avg-alpha)/t;
     }
 
-    if(t>0 && t%1000==0){
+    if(t>0 && t%1==0){
       fprintf(stderr,"%8d % .8e % .8e % .8e % .8e\n",t, __real__ avg, __imag__ avg, __real__ alpha, __imag__ alpha);
       printf("%8d % .8e % .8e % .8e % .8e\n",t, __real__ avg, __imag__ avg, __real__ alpha, __imag__ alpha);
     }
-- 
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