From e081cc3bddbb537868d5e8885fc5acac33672f2d Mon Sep 17 00:00:00 2001
From: Saad Jbabdi <saad@fmrib.ox.ac.uk>
Date: Tue, 12 Jun 2012 10:28:48 +0000
Subject: [PATCH] init d using L1 instead of MD
---
diffmodels.cc | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/diffmodels.cc b/diffmodels.cc
index 57581a6..b452e26 100644
--- a/diffmodels.cc
+++ b/diffmodels.cc
@@ -454,7 +454,8 @@ void PVM_single_c::fit(){
ColumnVector start(nparams);
//Initialize the non-linear fitter. Use the DTI estimates for most parameters, apart from the volume fractions
start(1) = dti.get_s0();
- start(2) = d2lambda(dti.get_md()>0?dti.get_md()*2:0.001); // empirically found that d~2*MD
+ //start(2) = d2lambda(dti.get_md()>0?dti.get_md()*2:0.001); // empirically found that d~2*MD
+ start(2) = d2lambda(dti.get_l1()>0?dti.get_l1():0.002); // empirically found that d~L1
start(4) = _th;
start(5) = _ph;
for(int ii=2,i=6;ii<=nfib;ii++,i+=3){
@@ -1044,6 +1045,7 @@ void PVM_single::fit(){
// initialise with a tensor
DTI dti(Y,bvecs,bvals);
dti.linfit();
+ //dti.print();
// set starting parameters for nonlinear fitting
float _th,_ph;
@@ -1051,7 +1053,8 @@ void PVM_single::fit(){
ColumnVector start(nparams);
start(1) = dti.get_s0();
- start(2) = dti.get_md()>0?dti.get_md()*2:0.001; // empirically found that d~2*MD
+ //start(2) = dti.get_md()>0?dti.get_md()*2:0.001; // empirically found that d~2*MD
+ start(2) = dti.get_l1()>0?dti.get_l1():0.002; // empirically found that d~L1
start(3) = dti.get_fa()<1?f2x(dti.get_fa()):f2x(0.95); // first pvf = FA
start(4) = _th;
start(5) = _ph;
@@ -1364,8 +1367,10 @@ boost::shared_ptr<BFMatrix> PVM_single::hess(const NEWMAT::ColumnVector& p,boost
void PVM_multi::fit(){
// initialise with simple pvm
- PVM_single pvm1(Y,bvecs,bvals,nfib,m_include_f0);
+ PVM_single_c pvm1(Y,bvecs,bvals,nfib,m_include_f0);
pvm1.fit();
+ //cout<<"Init with single"<<endl;
+ //pvm1.print();
float _a,_b;
_a = 1.0; // start with d=d_std
--
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