From fb767445d06a9c8164f1c0650a556f7c612b713f Mon Sep 17 00:00:00 2001
From: Fabian Brinkmann <fabian.brinkmann@mailbox.org>
Date: Fri, 24 Apr 2026 12:11:06 +0200
Subject: [PATCH 1/4] add GSL_PREFIX for custom GSL path

---
 mesh2hrtf/NumCalc/src/Makefile | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/mesh2hrtf/NumCalc/src/Makefile b/mesh2hrtf/NumCalc/src/Makefile
index a7624f95..a96211b5 100644
--- a/mesh2hrtf/NumCalc/src/Makefile
+++ b/mesh2hrtf/NumCalc/src/Makefile
@@ -8,15 +8,17 @@ EXECUTABLE=../bin/NumCalc
 GSLFLAG=-DUSE_GSL
 LAPACKFLAG=-DUSE_LAPACK
 OPTIM=-O2
-LDFLAGS=-llapacke -lgsl -lblas
+GSL_PREFIX ?= /usr/local
+LDFLAGS=-llapacke -lgsl -lblas -L$(GSL_PREFIX)/lib
+CFLAGS+=-I$(GSL_PREFIX)/include
 #DEBUG=-g
 
 all: $(SOURCES) $(EXECUTABLE)
 
-$(EXECUTABLE): $(OBJECTS) 
+$(EXECUTABLE): $(OBJECTS)
 	$(CC) $(OBJECTS) $(LDFLAGS) $(OPTIM) $(GSLFLAG) $(LAPACKFLAG) -o $@
 
 .cpp.o:
-	$(CC) $(CFLAGS) $(DEBUG) $(OPTIM) $< 
+	$(CC) $(CFLAGS) $(DEBUG) $(OPTIM) $(GSLFLAG) $(LAPACKFLAG) $<
 clean:
 	rm *.o

From ff8913f4889def19e2446370e143328afd91d01d Mon Sep 17 00:00:00 2001
From: Fabian Brinkmann <fabian.brinkmann@mailbox.org>
Date: Fri, 24 Apr 2026 12:11:35 +0200
Subject: [PATCH 2/4] explicit cmath include and system agnostic gsl include

---
 mesh2hrtf/NumCalc/src/NC_MLFMM.h | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mesh2hrtf/NumCalc/src/NC_MLFMM.h b/mesh2hrtf/NumCalc/src/NC_MLFMM.h
index 7ef9e229..e1557131 100644
--- a/mesh2hrtf/NumCalc/src/NC_MLFMM.h
+++ b/mesh2hrtf/NumCalc/src/NC_MLFMM.h
@@ -7,15 +7,14 @@
 #include<gsl/gsl_sf_bessel.h>
 #include<gsl/gsl_sf_legendre.h>
 #include<vector>
-#include <bits/stdc++.h>
-//#include<x86_64-linux-gnu/cblas64_mangling.h>
+#include<cmath>
+#include<gsl/gsl_cblas.h>
 
-#include<x86_64-linux-gnu/cblas64.h>
 extern Vector<double> Sourpoi3;
 extern Vector<double> Norvci3;
 extern void BAsinguII(ofstream&, Vector<Complex>&, const int&,
 	       const int&, Vector<Complex>&, Matrix<double>&,
-	       const int&, const int&); 
+	       const int&, const int&);
 extern void BAreguII(ofstream&, Vector<Complex>&, const int&,
 	    const int&, const int&, const int&,
 	    Vector<Complex>&, Matrix<double>&,

From a9ba3d4262bfc3e8568ae1d8d46501447cf1c262 Mon Sep 17 00:00:00 2001
From: Fabian Brinkmann <fabian.brinkmann@mailbox.org>
Date: Fri, 24 Apr 2026 12:12:16 +0200
Subject: [PATCH 3/4] encpsulate legendre call

---
 mesh2hrtf/NumCalc/src/NC_MLFMM.cpp | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/mesh2hrtf/NumCalc/src/NC_MLFMM.cpp b/mesh2hrtf/NumCalc/src/NC_MLFMM.cpp
index 472f1cb1..f6fdc423 100644
--- a/mesh2hrtf/NumCalc/src/NC_MLFMM.cpp
+++ b/mesh2hrtf/NumCalc/src/NC_MLFMM.cpp
@@ -584,9 +584,14 @@ void Get_Interpolation_Matrices(double** Ylev, int nlevels) {
 	  if( l == 0 )
 	    //	    Ylev[lev-1][i * Ncurrent + j] = 0.25/PI;
 	    Ylev[lev-1][i * Ncurrent + j] = 1.0;
-	  else
+	  else {
 	    //	    Ylev[lev-1][i * Ncurrent + j] += (2.0 * double(l) + 1.0) / (4.0 * PI) * legendre(l,Angle);
+#ifdef USE_GSL
+	    Ylev[lev-1][i * Ncurrent + j] += (2.0 * double(l) + 1.0) * gsl_sf_legendre_Pl(l,Angle);
+#else
 	    Ylev[lev-1][i * Ncurrent + j] += (2.0 * double(l) + 1.0) * legendre(l,Angle);
+#endif
+	  }
 	}
       }
     }

From 7ce0d1cd86a604f33f1d42e5ced9701438e26992 Mon Sep 17 00:00:00 2001
From: Fabian Brinkmann <fabian.brinkmann@mailbox.org>
Date: Tue, 28 Apr 2026 11:23:44 +0200
Subject: [PATCH 4/4] add lapack prefix

---
 mesh2hrtf/NumCalc/src/Makefile | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/mesh2hrtf/NumCalc/src/Makefile b/mesh2hrtf/NumCalc/src/Makefile
index a96211b5..c37cf14a 100644
--- a/mesh2hrtf/NumCalc/src/Makefile
+++ b/mesh2hrtf/NumCalc/src/Makefile
@@ -9,8 +9,10 @@ GSLFLAG=-DUSE_GSL
 LAPACKFLAG=-DUSE_LAPACK
 OPTIM=-O2
 GSL_PREFIX ?= /usr/local
-LDFLAGS=-llapacke -lgsl -lblas -L$(GSL_PREFIX)/lib
+LAPACK_PREFIX ?= /usr/local
+LDFLAGS=-L$(LAPACK_PREFIX)/lib -L$(GSL_PREFIX)/lib -llapacke -lgsl -lblas
 CFLAGS+=-I$(GSL_PREFIX)/include
+CFLAGS+=-I$(LAPACK_PREFIX)/include
 #DEBUG=-g
 
 all: $(SOURCES) $(EXECUTABLE)