diff --git a/examples/hexagonal/modes/00_params.sh b/examples/hexagonal/modes/00_params.sh
index 050c80f..367bf54 100644
--- a/examples/hexagonal/modes/00_params.sh
+++ b/examples/hexagonal/modes/00_params.sh
@@ -27,6 +27,11 @@ export B2Y_nmi=$(bc <<< '4*pi/3/'${SEPARATION_nm})
 export KPOINTX_nmi=$(bc <<< '4*pi/3/sqrt(3)'/${SEPARATION_nm})
 export KPOINTY_nmi=0.0 #$(bc <<< '4*pi/3/sqrt(3)'/${SEPARATION_nm})
 
+# a M-point coordinates
+export MPOINTX_nmi=0.0 
+export MPOINTY_nmi=$(bc <<< '2*pi/3'/${SEPARATION_nm})
+
+
 export RADIUS_nm=50
 export HEIGHT_nm=50
 export METAL=Au
diff --git a/examples/hexagonal/modes/01_compute_modes.sh b/examples/hexagonal/modes/01_compute_modes.sh
index 1741fc9..2114f7d 100755
--- a/examples/hexagonal/modes/01_compute_modes.sh
+++ b/examples/hexagonal/modes/01_compute_modes.sh
@@ -13,4 +13,6 @@ ${MISCDIR}/lat2d_modes.py \
 	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
 	-k s${KPOINTX_nmi}e9 s${KPOINTY_nmi}e9 \
 	-d -3 \
+	-t 0.01 \
+	-c 250 \
 	-P
diff --git a/examples/hexagonal/modes/02_compute_disp.sh b/examples/hexagonal/modes/02_compute_disp.sh
new file mode 100755
index 0000000..be70113
--- /dev/null
+++ b/examples/hexagonal/modes/02_compute_disp.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for bbb in 1 -2 -3 -4 ; do
+  for coeff in $(seq 0.80 0.01 1.50 | sed -e s/,/./g) ; do
+    ${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-p s${P2X_nm}e-9 s${P2Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s$(bc <<< ${KPOINTX_nmi}*${coeff})e9 s$(bc <<< ${KPOINTY_nmi}*${coeff})e9 \
+	-d $bbb \
+	-t 1e13 \
+	-T 0.2 \
+	-c 250 
+  done
+done
diff --git a/examples/hexagonal/modes/02b_compute_disp_0M.sh b/examples/hexagonal/modes/02b_compute_disp_0M.sh
new file mode 100755
index 0000000..969c028
--- /dev/null
+++ b/examples/hexagonal/modes/02b_compute_disp_0M.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for bbb in 1 -2 -3 -4 ; do
+  for coeff in $(seq 0.00 0.01 1.00 | sed -e s/,/./g) ; do
+    ${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-p s${P2X_nm}e-9 s${P2Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s$(bc <<< ${MPOINTX_nmi}*${coeff})e9 s$(bc <<< ${MPOINTY_nmi}*${coeff})e9 \
+	-d $bbb \
+	-t 1e12 \
+	-T 0.3 \
+	-c 250 \
+	-P
+  done
+done
+
diff --git a/examples/hexagonal/modes/02x_compute_disp.sh b/examples/hexagonal/modes/02x_compute_disp.sh
new file mode 100755
index 0000000..911a43f
--- /dev/null
+++ b/examples/hexagonal/modes/02x_compute_disp.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for bbb in 1 2 ; do
+  for coeff in $(seq 0.80 0.01 2.00 | sed -e s/,/./g) ; do
+    ${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-p s${P2X_nm}e-9 s${P2Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s$(bc <<< ${KPOINTX_nmi}*${coeff})e9 s$(bc <<< ${KPOINTY_nmi}*${coeff})e9 \
+	-d -$bbb \
+	-t 1e12 \
+	-T 0.2 \
+	-c 250 \
+	-P
+  done
+done
+
diff --git a/examples/rectangular/modes/00_params.sh b/examples/rectangular/modes/00_params.sh
new file mode 100644
index 0000000..49cf6fc
--- /dev/null
+++ b/examples/rectangular/modes/00_params.sh
@@ -0,0 +1,37 @@
+#!/bin/bash
+
+# Common parameters for a rectangular array
+# N.B. We put those into bc, which does not understant exponential notation
+
+export PX_nm=375
+export PY_nm=375
+export RADIUS_nm=30
+export HEIGHT_nm=30
+export METAL=Ag
+export BG_REFINDEX=1.52
+
+
+# Setup bc
+
+echo 'scale=20;pi=3.14159265358979323846;' > bc_env
+export BC_ENV_ARGS="bc_env"
+
+
+# We have only one particle per unit cell here
+export P1X_nm=0
+export P1Y_nm=0
+
+
+# Lattice vectors (for the general scripts)
+export A1X_nm=${PX_nm}
+export A1Y_nm=0
+export A2X_nm=0
+export A2Y_nm=${PY_nm}
+
+# Reciprocal lattice vectors
+export B1X_nmi=$(bc <<< '1/'${PX_nm})
+export B1Y_nmi=0
+export B2X_nmi=0
+export B2Y_nmi=$(bc <<< '1/'${PY_nm})
+
+
diff --git a/examples/rectangular/modes/01_compute_modes.sh b/examples/rectangular/modes/01_compute_modes.sh
new file mode 100755
index 0000000..2114f7d
--- /dev/null
+++ b/examples/rectangular/modes/01_compute_modes.sh
@@ -0,0 +1,18 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-p s${P2X_nm}e-9 s${P2Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s${KPOINTX_nmi}e9 s${KPOINTY_nmi}e9 \
+	-d -3 \
+	-t 0.01 \
+	-c 250 \
+	-P
diff --git a/examples/rectangular/modes/01a_realfreq_svd.sh b/examples/rectangular/modes/01a_realfreq_svd.sh
new file mode 100755
index 0000000..dae7277
--- /dev/null
+++ b/examples/rectangular/modes/01a_realfreq_svd.sh
@@ -0,0 +1,17 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+# try several lMaxes
+
+${MISCDIR}/lat2d_realfreqsvd.py \
+       	-B $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-L 2 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k 0 0 \
+	-F 2.001 0.001 2.250  \
+	-P
diff --git a/examples/rectangular/modes/01b_realfreq_svd_sym.sh b/examples/rectangular/modes/01b_realfreq_svd_sym.sh
new file mode 100755
index 0000000..9e5db87
--- /dev/null
+++ b/examples/rectangular/modes/01b_realfreq_svd_sym.sh
@@ -0,0 +1,15 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+
+for LMAX in 1 2 3 ; do  # try several cutoffs
+  ${MISCDIR}/infiniterectlat-k0realfreqsvd.py \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L $LMAX -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-F 2.001 0.001 2.250  \
+	-P
+done
diff --git a/examples/rectangular/modes/02_compute_disp.sh b/examples/rectangular/modes/02_compute_disp.sh
new file mode 100755
index 0000000..be70113
--- /dev/null
+++ b/examples/rectangular/modes/02_compute_disp.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for bbb in 1 -2 -3 -4 ; do
+  for coeff in $(seq 0.80 0.01 1.50 | sed -e s/,/./g) ; do
+    ${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-p s${P2X_nm}e-9 s${P2Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s$(bc <<< ${KPOINTX_nmi}*${coeff})e9 s$(bc <<< ${KPOINTY_nmi}*${coeff})e9 \
+	-d $bbb \
+	-t 1e13 \
+	-T 0.2 \
+	-c 250 
+  done
+done
diff --git a/examples/rectangular/modes/02b_compute_disp_0M.sh b/examples/rectangular/modes/02b_compute_disp_0M.sh
new file mode 100755
index 0000000..969c028
--- /dev/null
+++ b/examples/rectangular/modes/02b_compute_disp_0M.sh
@@ -0,0 +1,24 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for bbb in 1 -2 -3 -4 ; do
+  for coeff in $(seq 0.00 0.01 1.00 | sed -e s/,/./g) ; do
+    ${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-p s${P2X_nm}e-9 s${P2Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s$(bc <<< ${MPOINTX_nmi}*${coeff})e9 s$(bc <<< ${MPOINTY_nmi}*${coeff})e9 \
+	-d $bbb \
+	-t 1e12 \
+	-T 0.3 \
+	-c 250 \
+	-P
+  done
+done
+
diff --git a/examples/rectangular/modes/02x_compute_disp.sh b/examples/rectangular/modes/02x_compute_disp.sh
new file mode 100755
index 0000000..c17bfaa
--- /dev/null
+++ b/examples/rectangular/modes/02x_compute_disp.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for bbb in 1 -2 2 -3 ; do
+  for coeff in $(seq -0.200 0.010 0.200 | sed -e s/,/./g) ; do
+    ${MISCDIR}/lat2d_modes.py \
+       	-n $BG_REFINDEX \
+	-b s${A1X_nm}e-9 s${A1Y_nm}e-9 \
+	-b s${A2X_nm}e-9 s${A2Y_nm}e-9 \
+	-p s${P1X_nm}e-9 s${P1Y_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	-k s$(bc <<< ${B1X_nmi}*${coeff})e9 s$(bc <<< ${B1Y_nmi}*${coeff})e9 \
+	-d $bbb \
+	-T 0.2 \
+	-c 250 
+  done
+done
+
diff --git a/examples/rectangular/scattering/00_params.sh b/examples/rectangular/scattering/00_params.sh
new file mode 120000
index 0000000..9b3b9eb
--- /dev/null
+++ b/examples/rectangular/scattering/00_params.sh
@@ -0,0 +1 @@
+../modes/00_params.sh
\ No newline at end of file
diff --git a/examples/rectangular/scattering/01_scattering_infinite.sh b/examples/rectangular/scattering/01_scattering_infinite.sh
new file mode 100755
index 0000000..fe2c24f
--- /dev/null
+++ b/examples/rectangular/scattering/01_scattering_infinite.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in 0 1; do
+  ${MISCDIR}/infiniterectlat-scatter.py \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.015:0.015|201" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-f "s2.110:2.230|100" \
+	-P
+done
+
diff --git a/examples/rectangular/scattering/02_scattering_finite_single.sh b/examples/rectangular/scattering/02_scattering_finite_single.sh
new file mode 100755
index 0000000..9ee166c
--- /dev/null
+++ b/examples/rectangular/scattering/02_scattering_finite_single.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in 1; do
+  ${MISCDIR}/finiterectlat-scatter.py \
+	--size 5 5\
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 2 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.05:0.05|101" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-f 2.15
+done
+
diff --git a/examples/rectangular/scattering/02b_scattering_infinite_single.sh b/examples/rectangular/scattering/02b_scattering_infinite_single.sh
new file mode 100755
index 0000000..1af5c7a
--- /dev/null
+++ b/examples/rectangular/scattering/02b_scattering_infinite_single.sh
@@ -0,0 +1,19 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in 0 1; do
+  ${MISCDIR}/infiniterectlat-scatter.py \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 2 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.05:0.05|101" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-P \
+	-f 2.15
+done
+
diff --git a/examples/rectangular/scattering/02c_scattering_finite_single_huge.sh b/examples/rectangular/scattering/02c_scattering_finite_single_huge.sh
new file mode 100755
index 0000000..eee8bfd
--- /dev/null
+++ b/examples/rectangular/scattering/02c_scattering_finite_single_huge.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+##SBATCH --mem=50000
+##SBATCH -c 12
+##SBATCH -t 14:00:00
+##SBATCH -p batch
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in 0 1; do
+  ${MISCDIR}/finiterectlat-scatter.py \
+	--size 140 100 \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 2 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.05:0.05|101" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-o 140x100.npz -O 140x100.pdf \
+	-P \
+	-f 2.15
+done
+
diff --git a/examples/rectangular/scattering/02d_scattering_finite_single_big.sh b/examples/rectangular/scattering/02d_scattering_finite_single_big.sh
new file mode 100755
index 0000000..0da17f3
--- /dev/null
+++ b/examples/rectangular/scattering/02d_scattering_finite_single_big.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+##SBATCH --mem=30000
+##SBATCH -c 12
+##SBATCH -t 14:00:00
+##SBATCH -p batch
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in  1; do
+  ${MISCDIR}/finiterectlat-scatter.py \
+	--size 100 100 \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 2 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.05:0.05|101" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-o 100x100.npz -O 100x100.pdf \
+	-P \
+	-f 2.15
+done
+
diff --git a/examples/rectangular/scattering/02e_scattering_finite_single_huge.sh b/examples/rectangular/scattering/02e_scattering_finite_single_huge.sh
new file mode 100755
index 0000000..2366206
--- /dev/null
+++ b/examples/rectangular/scattering/02e_scattering_finite_single_huge.sh
@@ -0,0 +1,25 @@
+#!/bin/bash
+##SBATCH --mem=50000
+##SBATCH -c 12
+##SBATCH -t 14:00:00
+##SBATCH -p batch
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in 0 1; do
+  ${MISCDIR}/finiterectlat-scatter.py \
+	--size 140 140 \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 2 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.05:0.05|101" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-o 140x140.npz -O 140x140.pdf \
+	-P \
+	-f 2.15
+done
+
diff --git a/examples/rectangular/scattering/03_scattering_finite.sh b/examples/rectangular/scattering/03_scattering_finite.sh
new file mode 100755
index 0000000..d1156a8
--- /dev/null
+++ b/examples/rectangular/scattering/03_scattering_finite.sh
@@ -0,0 +1,21 @@
+#!/bin/bash
+SCRIPTDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
+MISCDIR=../../../misc
+
+source ${SCRIPTDIR}/00_params.sh
+
+for PSI in 1; do
+  ${MISCDIR}/finiterectlat-scatter.py \
+	--size 20 20 \
+       	-B $BG_REFINDEX \
+	-p ${PX_nm}e-9 ${PY_nm}e-9 \
+	-L 3 -m $METAL -r ${RADIUS_nm}e-9 -H ${HEIGHT_nm}e-9 \
+	--theta "s-0.005:0.005|101" \
+	--phi 0 \
+        --psi $PSI \
+	--chi 0	\
+	-P \
+	-f "s2.150:2.180|100" \
+	
+done
+
diff --git a/misc/infiniterectlat-k0realfreqsvd.py b/misc/infiniterectlat-k0realfreqsvd.py
index 4e8f8d6..fb85093 100755
--- a/misc/infiniterectlat-k0realfreqsvd.py
+++ b/misc/infiniterectlat-k0realfreqsvd.py
@@ -22,8 +22,8 @@ thegroup = 'D4h' if px == py and not a.D2 else 'D2h'
 
 particlestr = ("sph" if a.height is None else "cyl") + ("_r%gnm" % (a.radius*1e9))
 if a.height is not None: particlestr += "_h%gnm" % (a.height * 1e9)
-defaultprefix = "%s_p%gnmx%gnm_m%s_n%g_f(%g..%g..%g)eV_L%d_SVGamma" % (
-    particlestr, px*1e9, py*1e9, str(a.material), a.refractive_index, *(a.eV_seq), a.lMax)
+defaultprefix = "%s_p%gnmx%gnm_m%s_bg%s_f(%g..%g..%g)eV_L%d_SVGamma" % (
+    particlestr, px*1e9, py*1e9, str(a.material), str(a.background), *(a.eV_seq), a.lMax)
 logging.info("Default file prefix: %s" % defaultprefix)
 
 
@@ -87,6 +87,8 @@ for i, omega in enumerate(omegas):
     with pgsl_ignore_error(15): # avoid gsl crashing on underflow; maybe not needed
         ImTW = ssw.modeproblem_matrix_full(k)
     for iri in range(ss1.nirreps):
+        if ss1.saecv_sizes[iri] == 0:
+            continue
         ImTW_packed = ss1.pack_matrix(ImTW, iri)
         SVs[iri][i] = np.linalg.svd(ImTW_packed, compute_uv = False)