Execution Chart

We display below the execution chart for this examination (boot time has been removed).

Trace from the execution

Formatting '/local/x2003239/mcc2020-input.r194-csrt-159033389500110.qcow2', fmt=qcow2 size=4294967296 backing_file=/local/x2003239/mcc2020-input.qcow2 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
Waiting for the VM to be ready (probing ssh)
...........................................................................................................................................................................................................................................................................................................................................
=====================================================================
Generated by BenchKit 2-4028
Executing tool itslola
Input is SmallOperatingSystem-PT-MT2048DC0512, examination is ReachabilityCardinality
Time confinement is 3600 seconds
Memory confinement is 16384 MBytes
Number of cores is 4
Run identifier is r194-csrt-159033389500110
=====================================================================

--------------------
preparation of the directory to be used:
/home/mcc/execution
total 208K
-rw-r--r-- 1 mcc users 3.7K Apr 12 17:46 CTLCardinality.txt
-rw-r--r-- 1 mcc users 17K Apr 12 17:46 CTLCardinality.xml
-rw-r--r-- 1 mcc users 3.4K Apr 11 20:04 CTLFireability.txt
-rw-r--r-- 1 mcc users 20K Apr 11 20:04 CTLFireability.xml
-rw-r--r-- 1 mcc users 4.0K Mar 24 05:38 GenericPropertiesDefinition.xml
-rw-r--r-- 1 mcc users 6.3K Mar 24 05:38 GenericPropertiesVerdict.xml
-rw-r--r-- 1 mcc users 4.1K Apr 14 12:52 LTLCardinality.txt
-rw-r--r-- 1 mcc users 24K Apr 28 14:02 LTLCardinality.xml
-rw-r--r-- 1 mcc users 2.5K Apr 14 12:52 LTLFireability.txt
-rw-r--r-- 1 mcc users 17K Apr 28 14:02 LTLFireability.xml
-rw-r--r-- 1 mcc users 4.8K Apr 10 20:34 ReachabilityCardinality.txt
-rw-r--r-- 1 mcc users 21K Apr 10 20:34 ReachabilityCardinality.xml
-rw-r--r-- 1 mcc users 3.3K Apr 10 05:24 ReachabilityFireability.txt
-rw-r--r-- 1 mcc users 17K Apr 10 05:24 ReachabilityFireability.xml
-rw-r--r-- 1 mcc users 2.1K Apr 10 22:29 UpperBounds.txt
-rw-r--r-- 1 mcc users 4.1K Apr 10 22:29 UpperBounds.xml
-rw-r--r-- 1 mcc users 6 Mar 24 05:38 equiv_col
-rw-r--r-- 1 mcc users 13 Mar 24 05:38 instance
-rw-r--r-- 1 mcc users 6 Mar 24 05:38 iscolored
-rw-r--r-- 1 mcc users 8.1K Mar 24 05:38 model.pnml

--------------------
content from stdout:

=== Data for post analysis generated by BenchKit (invocation template)

The expected result is a vector of booleans
BOOL_VECTOR

here is the order used to build the result vector(from text file)
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-00
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-01
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-02
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-03
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-04
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-05
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-06
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-07
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-08
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-09
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-10
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-11
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-12
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-13
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-14
FORMULA_NAME SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-15

=== Now, execution of the tool begins

BK_START 1591201430751

bash -c /home/mcc/BenchKit/BenchKit_head.sh 2> STDERR ; echo ; echo -n "BK_STOP " ; date -u +%s%3N
[2020-06-03 16:23:52] [INFO ] Running its-tools with arguments : [-pnfolder, /home/mcc/execution, -examination, ReachabilityCardinality, -z3path, /home/mcc/BenchKit//z3/bin/z3, -yices2path, /home/mcc/BenchKit//yices/bin/yices, -timeout, 3600, -rebuildPNML]
[2020-06-03 16:23:52] [INFO ] Parsing pnml file : /home/mcc/execution/model.pnml
[2020-06-03 16:23:53] [INFO ] Load time of PNML (sax parser for PT used): 26 ms
[2020-06-03 16:23:53] [INFO ] Transformed 9 places.
[2020-06-03 16:23:53] [INFO ] Transformed 8 transitions.
[2020-06-03 16:23:53] [INFO ] Parsed PT model containing 9 places and 8 transitions in 70 ms.
Parsed 16 properties from file /home/mcc/execution/ReachabilityCardinality.xml in 16 ms.
Working with output stream class java.io.PrintStream
Incomplete random walk after 10258 steps, including 0 resets, run finished after 11 ms. (steps per millisecond=932 ) properties seen :[0, 0, 0, 0, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0]
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-06 FALSE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-05 TRUE TECHNIQUES TOPOLOGICAL RANDOM_WALK
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-04 FALSE TECHNIQUES TOPOLOGICAL RANDOM_WALK
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 29 ms. (steps per millisecond=344 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 18 ms. (steps per millisecond=555 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 19 ms. (steps per millisecond=526 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 12 ms. (steps per millisecond=833 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 12 ms. (steps per millisecond=833 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 10 ms. (steps per millisecond=1000 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 17 ms. (steps per millisecond=588 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 12 ms. (steps per millisecond=833 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 11 ms. (steps per millisecond=909 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 10 ms. (steps per millisecond=1000 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10000 steps, including 0 resets, run finished after 5 ms. (steps per millisecond=2000 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 11 ms. (steps per millisecond=909 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Incomplete Best-First random walk after 10001 steps, including 0 resets, run finished after 8 ms. (steps per millisecond=1250 ) properties seen :[0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
// Phase 1: matrix 8 rows 9 cols
[2020-06-03 16:23:53] [INFO ] Computed 4 place invariants in 2 ms
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using 4 positive place invariants in 12 ms returned unsat
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using 4 positive place invariants in 8 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using state equation in 28 ms returned sat
[2020-06-03 16:23:53] [INFO ] Solution in real domain found non-integer solution.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using 4 positive place invariants in 14 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using state equation in 31 ms returned sat
[2020-06-03 16:23:53] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 3 ms.
[2020-06-03 16:23:53] [INFO ] Added : 6 causal constraints over 2 iterations in 41 ms. Result :sat
Attempting to minimize the solution found.
Minimization took 4 ms.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using 4 positive place invariants in 2 ms returned unsat
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using 4 positive place invariants in 5 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using state equation in 53 ms returned sat
[2020-06-03 16:23:53] [INFO ] Solution in real domain found non-integer solution.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using 4 positive place invariants in 7 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using state equation in 7 ms returned sat
[2020-06-03 16:23:53] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 1 ms.
[2020-06-03 16:23:53] [INFO ] Added : 6 causal constraints over 2 iterations in 13 ms. Result :sat
Attempting to minimize the solution found.
Minimization took 1 ms.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using 4 positive place invariants in 2 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using state equation in 37 ms returned sat
[2020-06-03 16:23:53] [INFO ] Solution in real domain found non-integer solution.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using 4 positive place invariants in 3 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using state equation in 9 ms returned sat
[2020-06-03 16:23:53] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 2 ms.
[2020-06-03 16:23:53] [INFO ] Added : 6 causal constraints over 2 iterations in 12 ms. Result :sat
Attempting to minimize the solution found.
Minimization took 9 ms.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using 4 positive place invariants in 3 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Real]Absence check using state equation in 6 ms returned sat
[2020-06-03 16:23:53] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 1 ms.
[2020-06-03 16:23:53] [INFO ] Solution in real domain found non-integer solution.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using 4 positive place invariants in 5 ms returned sat
[2020-06-03 16:23:53] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:53] [INFO ] [Nat]Absence check using state equation in 10 ms returned sat
[2020-06-03 16:23:53] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 6 ms.
[2020-06-03 16:23:54] [INFO ] Added : 6 causal constraints over 2 iterations in 51 ms. Result :sat
Attempting to minimize the solution found.
Minimization took 1 ms.
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 2 ms returned unsat
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 2 ms returned unsat
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 1 ms returned unsat
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 3 ms returned sat
[2020-06-03 16:23:54] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using state equation in 9 ms returned sat
[2020-06-03 16:23:54] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 1 ms.
[2020-06-03 16:23:54] [INFO ] Solution in real domain found non-integer solution.
[2020-06-03 16:23:54] [INFO ] [Nat]Absence check using 4 positive place invariants in 4 ms returned sat
[2020-06-03 16:23:54] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:54] [INFO ] [Nat]Absence check using state equation in 8 ms returned sat
[2020-06-03 16:23:54] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 1 ms.
[2020-06-03 16:23:54] [INFO ] Added : 6 causal constraints over 2 iterations in 8 ms. Result :sat
Attempting to minimize the solution found.
Minimization took 4 ms.
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 2 ms returned sat
[2020-06-03 16:23:54] [INFO ] [Real]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using state equation in 6 ms returned sat
[2020-06-03 16:23:54] [INFO ] Solution in real domain found non-integer solution.
[2020-06-03 16:23:54] [INFO ] [Nat]Absence check using 4 positive place invariants in 65 ms returned sat
[2020-06-03 16:23:54] [INFO ] [Nat]Adding state equation constraints to refine reachable states.
[2020-06-03 16:23:54] [INFO ] [Nat]Absence check using state equation in 68 ms returned sat
[2020-06-03 16:23:54] [INFO ] Computed and/alt/rep : 7/10/7 causal constraints in 2 ms.
[2020-06-03 16:23:54] [INFO ] Added : 6 causal constraints over 2 iterations in 37 ms. Result :sat
Attempting to minimize the solution found.
Minimization took 1 ms.
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 1 ms returned unsat
[2020-06-03 16:23:54] [INFO ] [Real]Absence check using 4 positive place invariants in 8 ms returned unsat
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-15 TRUE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-14 TRUE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-11 TRUE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-10 FALSE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-09 FALSE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-02 TRUE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-00 FALSE TECHNIQUES STRUCTURAL_REDUCTION TOPOLOGICAL SAT_SMT
Incomplete Parikh walk after 308200 steps, including 99 resets, run finished after 267 ms. (steps per millisecond=1154 ) properties seen :[0, 0, 0, 0, 0, 1] could not realise parikh vector
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-13 FALSE TECHNIQUES TOPOLOGICAL PARIKH_WALK
Incomplete Parikh walk after 410800 steps, including 98 resets, run finished after 366 ms. (steps per millisecond=1122 ) properties seen :[0, 0, 1, 0, 1] could not realise parikh vector
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-12 TRUE TECHNIQUES TOPOLOGICAL PARIKH_WALK
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-07 TRUE TECHNIQUES TOPOLOGICAL PARIKH_WALK
Incomplete Parikh walk after 819800 steps, including 99 resets, run finished after 488 ms. (steps per millisecond=1679 ) properties seen :[1, 0, 1] could not realise parikh vector
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-08 TRUE TECHNIQUES TOPOLOGICAL PARIKH_WALK
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-01 FALSE TECHNIQUES TOPOLOGICAL PARIKH_WALK
Incomplete Parikh walk after 666200 steps, including 99 resets, run finished after 321 ms. (steps per millisecond=2075 ) properties seen :[0] could not realise parikh vector
Finished Parikh walk after 4100 steps, including 0 resets, run visited all 1 properties in 3 ms. (steps per millisecond=1366 )
FORMULA SmallOperatingSystem-PT-MT2048DC0512-ReachabilityCardinality-03 FALSE TECHNIQUES TOPOLOGICAL PARIKH_WALK
All properties solved without resorting to model-checking.

--------------------
content from stderr:

Sequence of Actions to be Executed by the VM

This is useful if one wants to reexecute the tool in the VM from the submitted image disk.

set -x
# this is for BenchKit: configuration of major elements for the test
export BK_INPUT="SmallOperatingSystem-PT-MT2048DC0512"
export BK_EXAMINATION="ReachabilityCardinality"
export BK_TOOL="itslola"
export BK_RESULT_DIR="/tmp/BK_RESULTS/OUTPUTS"
export BK_TIME_CONFINEMENT="3600"
export BK_MEMORY_CONFINEMENT="16384"

# this is specific to your benchmark or test

export BIN_DIR="$HOME/BenchKit/bin"

# remove the execution directoty if it exists (to avoid increse of .vmdk images)
if [ -d execution ] ; then
rm -rf execution
fi

# this is for BenchKit: explicit launching of the test
echo "====================================================================="
echo " Generated by BenchKit 2-4028"
echo " Executing tool itslola"
echo " Input is SmallOperatingSystem-PT-MT2048DC0512, examination is ReachabilityCardinality"
echo " Time confinement is $BK_TIME_CONFINEMENT seconds"
echo " Memory confinement is 16384 MBytes"
echo " Number of cores is 4"
echo " Run identifier is r194-csrt-159033389500110"
echo "====================================================================="
echo
echo "--------------------"
echo "preparation of the directory to be used:"

tar xzf /home/mcc/BenchKit/INPUTS/SmallOperatingSystem-PT-MT2048DC0512.tgz
mv SmallOperatingSystem-PT-MT2048DC0512 execution
cd execution
if [ "ReachabilityCardinality" = "ReachabilityDeadlock" ] || [ "ReachabilityCardinality" = "UpperBounds" ] || [ "ReachabilityCardinality" = "QuasiLiveness" ] || [ "ReachabilityCardinality" = "StableMarking" ] || [ "ReachabilityCardinality" = "Liveness" ] || [ "ReachabilityCardinality" = "OneSafe" ] || [ "ReachabilityCardinality" = "StateSpace" ]; then
rm -f GenericPropertiesVerdict.xml
fi
pwd
ls -lh

echo
echo "--------------------"
echo "content from stdout:"
echo
echo "=== Data for post analysis generated by BenchKit (invocation template)"
echo
if [ "ReachabilityCardinality" = "UpperBounds" ] ; then
echo "The expected result is a vector of positive values"
echo NUM_VECTOR
elif [ "ReachabilityCardinality" != "StateSpace" ] ; then
echo "The expected result is a vector of booleans"
echo BOOL_VECTOR
else
echo "no data necessary for post analysis"
fi
echo
if [ -f "ReachabilityCardinality.txt" ] ; then
echo "here is the order used to build the result vector(from text file)"
for x in $(grep Property ReachabilityCardinality.txt | cut -d ' ' -f 2 | sort -u) ; do
echo "FORMULA_NAME $x"
done
elif [ -f "ReachabilityCardinality.xml" ] ; then # for cunf (txt files deleted;-)
echo echo "here is the order used to build the result vector(from xml file)"
for x in $(grep '' ReachabilityCardinality.xml | cut -d '>' -f 2 | cut -d '<' -f 1 | sort -u) ; do
echo "FORMULA_NAME $x"
done
elif [ "ReachabilityCardinality" = "ReachabilityDeadlock" ] || [ "ReachabilityCardinality" = "QuasiLiveness" ] || [ "ReachabilityCardinality" = "StableMarking" ] || [ "ReachabilityCardinality" = "Liveness" ] || [ "ReachabilityCardinality" = "OneSafe" ] ; then
echo "FORMULA_NAME ReachabilityCardinality"
fi
echo
echo "=== Now, execution of the tool begins"
echo
echo -n "BK_START "
date -u +%s%3N
echo
timeout -s 9 $BK_TIME_CONFINEMENT bash -c "/home/mcc/BenchKit/BenchKit_head.sh 2> STDERR ; echo ; echo -n \"BK_STOP \" ; date -u +%s%3N"
if [ $? -eq 137 ] ; then
echo
echo "BK_TIME_CONFINEMENT_REACHED"
fi
echo
echo "--------------------"
echo "content from stderr:"
echo
cat STDERR ;