From 9229de8f7479af11bbbd42d6cd38e281638f57a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Heikki=20M=C3=A4ntysaari?= <heikki.mantysaari@jyu.fi>
Date: Mon, 3 Feb 2025 16:25:00 +0200
Subject: [PATCH] Add methods to refer to Wilson lines using lattice indices
Also new way of computing the lattice index from the coordinate.
Indices differ from previous version ones by 1 unit, no effect
in continuum limit/when averaging over configurations
---
src/ipglasma.cpp | 75 +++++++++++++++++++-----------------------------
src/ipglasma.hpp | 9 +++++-
2 files changed, 37 insertions(+), 47 deletions(-)
diff --git a/src/ipglasma.cpp b/src/ipglasma.cpp
index 912fc15..1b4a818 100644
--- a/src/ipglasma.cpp
+++ b/src/ipglasma.cpp
@@ -143,22 +143,20 @@ WilsonLine& IPGlasma::GetWilsonLine(double x, double y)
ApplyPeriodicBoundaryConditions(q);
x=q[0];
y=q[1];
- int xind = FindIndex(x, xcoords);
- int yind = FindIndex(y, ycoords);
-
+ std::vector<int> coords = LatticeCoordinates(x,y);
+
// Handle edges
- if (xind < 0)
- xind = 0;
- if (xind >= xcoords.size())
- xind = xcoords.size()-1;
-
- if (yind < 0)
- yind = 0;
- if (yind >= ycoords.size())
- yind = ycoords.size()-1;
- //cout << "Coordinates " << x << ", " << y << " indeces " << xind << ", " << yind << endl;
+ if (coords[0] < 0)
+ coords[0] = 0;
+ if (coords[0] >= xcoords.size())
+ coords[0] = xcoords.size()-1;
+
+ if (coords[1] < 0)
+ coords[1] = 0;
+ if (coords[1] >= ycoords.size())
+ coords[1] = ycoords.size()-1;
- return wilsonlines[ xind*xcoords.size() + yind];
+ return GetWilsonLine( WilsonLineCoordinate(coords[0],coords[1]));
}
@@ -452,38 +450,23 @@ void IPGlasma::SetSchwinger(bool s, double rc)
}
}
-/* Returns index i for which
- * vec[i]<=val
- * Assumes that vec[i]<vec[i+1]
- * If such index can't be found, returns -1
- */
-int FindIndex(double val, std::vector<double> &vec)
+std::vector<int> IPGlasma::LatticeCoordinates(double x, double y)
{
- if (val < vec[0]) return -1;
-
- int ind=-1;
-
- uint start=0; uint end=vec.size()-1;
- while(end-start>5)
- {
- int tmp = static_cast<int>((start+end)/2.0);
-
- if (vec[tmp]>=val)
- end=tmp;
- else
- start=tmp;
- }
-
-
- for (uint i=start; i<=end; i++)
- {
- if (vec[i]<=val and vec[i+1]>val)
- {
- ind=i;
- break;
- }
- }
- if (ind == -1) return vec.size()-1;
- return ind;
+ std::vector<int> ret;
+
+ // Note: My lattice is from -L/2 to L/2, so I need to shift the coordinates
+ x = x + xcoords[xcoords.size()-1];
+ y = y + ycoords[ycoords.size()-1];
+ double lattice_spacing = xcoords[1]-xcoords[0];
+
+ int ix = x/lattice_spacing;
+ int iy = y/lattice_spacing;
+
+ return std::vector<int> {ix, iy};
+}
+
+int IPGlasma::WilsonLineCoordinate(int xind, int yind)
+{
+ return xcoords.size()*xind + yind;
}
diff --git a/src/ipglasma.hpp b/src/ipglasma.hpp
index 1d3c1e3..2f8c522 100644
--- a/src/ipglasma.hpp
+++ b/src/ipglasma.hpp
@@ -32,7 +32,7 @@ public:
double Amplitude(double xpom, double q1[2], double q2[2]);
double AmplitudeImaginaryPart(double xpom, double q1[2], double q2[2] );
- WilsonLine& GetWilsonLine( double x, double y); // Find Wilson line that corresponds to the coordinate
+ WilsonLine& GetWilsonLine( double x, double y); // Find Wilson line at the given point (x,y) [GeV^-1]
std::string InfoStr();
@@ -48,6 +48,13 @@ public:
void SetSchwinger(bool s, double rc=0);
void ApplyPeriodicBoundaryConditions(double q[2]);
+ std::vector<int> LatticeCoordinates(double x, double y);
+ int WilsonLineCoordinate(int xind, int yind);
+ WilsonLine& GetWilsonLine(int i) { return wilsonlines[i]; }
+
+ double X(int ix) { return xcoords[ix]; }
+ double Y(int iy) { return ycoords[iy]; }
+
private:
--
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