I read some documents and all of them say that the Std CAN have higher priority than the Ext CAN because the SRR bit is always Recessive in EXT CAN when they have the same ID, but from my understanding it depends.
https://copperhilltech.com/blog/controller-area-network-can-bus-tutorial-extended-can-protocol/
To simplify, let's say we have message ID 0x1(Std CAN) and 0x1(Ext CAN) sending simultaneously on the same bus.
The arbitration field of the Std CAN be compared to Ext CAN should be like this:
Std CAN: 0 0 0 0 0 0 0 0 0 0 1 0 (The bold bit is RTR)
Ext CAN: 0 0 0 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 (The bold bits are SRR, IDE and RTR)
At the 11th bit, The node that sends Std CAN is sending 1 (Recessive bit), and the node that sends Ext CAN is sending 0 (Dominant bit), so the Ext CAN wins the bus access and the node that sends Std CAN switch to listen mode and not sending anything after that, so the SRR and IDE bits never be reached to decide the message is Ext CAN or Std CAN.
Is my above understanding correct?
Thank you in advance,
Yes, an 29 bit frame with RTR set has higher priority than an 11 bit frame without RTR, given the first 11 bits of the identifiers are identical. So saying that standard frames have higher priority than extended is a simplification.
RTR frames is a bit of an oddball case overall, as they may also have varied length in the DLC area even though there's no data at all in the frame.
Related
I have trained yolo model to detect 24 different classes and now when I'm trying to extract outputs of it, it returns 29 numbers for each prediction. Here they are:
0.605734 0.0720678 0.0147335 0.0434446 0.999661 0 0 0 0.999577 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
I suppose that last 24 numbers are scores for each class, first 4 are parameters of bbox, but what is 5th? It is always bigger than 0.9. I'm confused. Please, help me.
It's the probability that the specific box has an object
My question is similar to this thread Create dummies from column with multiple values in pandas
Objective: I would like to produce similar result below but using dask
In Pandas
import pandas as pd
df = pd.DataFrame({'fruit': ['Banana, , Apple, Dragon Fruit,,,', 'Kiwi,', 'Lemon, Apple, Banana', ',']})
df['fruit'].str.get_dummies(sep=',')
Which will output the following:
Apple Banana Dragon Fruit Banana Kiwi Lemon
0 1 1 0 1 1 0 0
1 0 0 0 0 0 1 0
2 0 1 1 0 0 0 1
3 0 0 0 0 0 0 0
get_dummies() above is of type <pandas.core.strings.StringMethods>
Now the problem is there is no get_dummies() for dask equivalent <dask.dataframe.accessor.StringAccessor>
How can I solve my problem using dask?
Apparently this is not possible in dask as we wouldn't know the output columns before hand. See https://github.com/dask/dask/issues/4403.
Consider this data table
NumberOfAccidents MeanDistance
1 5
3 0
0 NA
0 NA
6 1.2
2 0
the first feature is the number of accidents and the second is the average distance of these accidents to a certain point. It is obvious for a record with zero accident, there won't be a value for MeanDistance. However, imputing these missing values are not logical!
MY SOLUTION: I have decided to discretize the MeanDistance with NAs being a level (bin) and the rest of the data being in bins like: [0,1), [1,2.5), [2.5, Inf). the final table will look like this:
NumberOfAccidents NAs first_bin sec_bin third_bin
1 0 0 0 1
3 0 1 0 0
0 1 0 0 0
0 1 0 0 0
6 0 0 1 0
2 0 1 0 0
What is your idea with these types of missing values that cannot be imputed?
what is your solution to this problem?
It really depends on the domain and what you are trying to predict. Even though your solution is fine, I wouldn't bin the rest of the data as you did. Giving that the NumberOfAccidents feature already tells what MeanDistance have NA values, I would probably just impute 0 into the NA values (for computations) and leave the rest of the data as it is.
Nevertheless, there is no need to limit yourself, just try different approaches and keep the one that boost your KPI (Key Performance Indicator).
A MP neuron of NAND can be constructed using the truth table below:
P Q P(and not)Q
1 1 0
1 0 1
0 1 0
0 0 0
The neuron that shows this:
Inputs:
P +2
Q -1
If the threshold is 2
This will give an output of Y=1
My professor seemed confused and didn't clarify why this isn't correct when it is (to the best of my knowledge). Did he make a mistake or have i got this wrong?
A solution would be great.
Side note: I have sketched out this neuron but cannot draw on this page (new to SO).
First of all NAND is not "and not" but "not and", the logical table is
P Q NAND(P,Q)
1 1 0
1 0 1
0 1 1
0 0 1
second of all, there is nothing hard about NAND nor your gate. The "only" problematic one is XOR (and nXOR).
P Q XOR(P,Q)
1 1 0
1 0 1
0 1 1
0 0 0
So:
single perceptron can easily represent both NAND(p,q) = NOT(AND(p,q)) as well as AND(p, NOT(q)) (which you call NAND).
the impossible to represent gate is XOR and its negation.
Informix 11.70.TC5DE,
Windows Vista with Dual Core Processor, 8GB RAM, 1TB HDD:
During the installation of this server, I specified it was going to be used for a data warehousing application. These are the onconfig parameters the install script generated.
Can any of these parameters be changed to maximize the performance of the server?
#(onconfig.ol_informix1170) - for data warehousing app.
ROOTNAME rootdbs
ROOTPATH C:\PROGRA~1\IBM\Informix\11.70\OL_INF~2\dbspaces\rootdbs.000
ROOTOFFSET 0
ROOTSIZE 312992
MIRROR 0
MIRRORPATH
MIRROROFFSET 0
PHYSFILE 49152
PLOG_OVERFLOW_PATH
PHYSBUFF 512
LOGFILES 6
LOGSIZE 10000
DYNAMIC_LOGS 2
LOGBUFF 256
LTXHWM 70
LTXEHWM 80
MSGPATH C:\PROGRA~1\IBM\Informix\11.70\ol_informix1170_1.log
CONSOLE C:\PROGRA~1\IBM\Informix\11.70\ol_informix1170_1.con
TBLTBLFIRST 0
TBLTBLNEXT 0
TBLSPACE_STATS 1
DBSPACETEMP tempdbs
SBSPACETEMP
SBSPACENAME sbspace
SYSSBSPACENAME
ONDBSPACEDOWN 2
SERVERNUM 6
DBSERVERNAME ol_informix1170_1
DBSERVERALIASES dr_informix1170_1
NETTYPE olsoctcp,1,150,NET
LISTEN_TIMEOUT 60
MAX_INCOMPLETE_CONNECTIONS 1024
FASTPOLL 1
NS_CACHE host=900,service=900,user=900,group=900
MULTIPROCESSOR 0
VPCLASS cpu,num=1,noage
VP_MEMORY_CACHE_KB 0
SINGLE_CPU_VP 1
#VPCLASS aio,num=1
CLEANERS 2
AUTO_AIOVPS 1
DIRECT_IO 0
LOCKS 2000
DEF_TABLE_LOCKMODE page
RESIDENT 0
SHMBASE 0xc000000L
SHMVIRTSIZE 209920
SHMADD 6560
EXTSHMADD 8192
SHMTOTAL 0
SHMVIRT_ALLOCSEG 0,3
#SHMNOACCESS 0x70000000-0x7FFFFFFF
CKPTINTVL 300
AUTO_CKPTS 1
RTO_SERVER_RESTART 60
BLOCKTIMEOUT 3600
CONVERSION_GUARD 2
RESTORE_POINT_DIR $INFORMIXDIR\tmp
TXTIMEOUT 300
DEADLOCK_TIMEOUT 60
HETERO_COMMIT 0
TAPEDEV \\.\TAPE0
TAPEBLK 16
TAPESIZE 0
LTAPEDEV
LTAPEBLK 16
LTAPESIZE 0
BAR_ACT_LOG $INFORMIXDIR\tmp\bar_act.log
BAR_DEBUG_LOG $INFORMIXDIR\tmp\bar_dbug.log
BAR_DEBUG 0
BAR_MAX_BACKUP 0
BAR_RETRY 1
BAR_NB_XPORT_COUNT 20
BAR_XFER_BUF_SIZE 15
RESTARTABLE_RESTORE ON
BAR_PROGRESS_FREQ 0
BAR_BSALIB_PATH
BACKUP_FILTER
RESTORE_FILTER
BAR_PERFORMANCE 0
BAR_CKPTSEC_TIMEOUT 15
ISM_DATA_POOL ISMData
ISM_LOG_POOL ISMLogs
DD_HASHSIZE 31
DD_HASHMAX 10
DS_HASHSIZE 31
DS_POOLSIZE 127
PC_HASHSIZE 31
PC_POOLSIZE 127
PRELOAD_DLL_FILE
STMT_CACHE 0
STMT_CACHE_HITS 0
STMT_CACHE_SIZE 512
STMT_CACHE_NOLIMIT 0
STMT_CACHE_NUMPOOL 1
USEOSTIME 0
STACKSIZE 64
ALLOW_NEWLINE 0
USELASTCOMMITTED NONE
FILLFACTOR 90
MAX_FILL_DATA_PAGES 0
BTSCANNER num=1,threshold=5000,rangesize=-1,alice=6,compression=default
ONLIDX_MAXMEM 188928
MAX_PDQPRIORITY 100
DS_MAX_QUERIES 1
DS_TOTAL_MEMORY 188928
DS_MAX_SCANS 1
DS_NONPDQ_QUERY_MEM 188928
DATASKIP
OPTCOMPIND 2
DIRECTIVES 1
EXT_DIRECTIVES 0
OPT_GOAL -1
IFX_FOLDVIEW 0
AUTO_REPREPARE 1
USTLOW_SAMPLE 0
RA_PAGES 64
RA_THRESHOLD 16
BATCHEDREAD_TABLE 1
BATCHEDREAD_INDEX 1
BATCHEDREAD_KEYONLY 0
EXPLAIN_STAT 1
#SQLTRACE level=low,ntraces=1000,size=2,mode=global
#DBCREATE_PERMISSION informix
#DB_LIBRARY_PATH
IFX_EXTEND_ROLE 1
SECURITY_LOCALCONNECTION
UNSECURE_ONSTAT
ADMIN_USER_MODE_WITH_DBSA
ADMIN_MODE_USERS
PLCY_POOLSIZE 127
PLCY_HASHSIZE 31
USRC_POOLSIZE 127
USRC_HASHSIZE 31
STAGEBLOB
OPCACHEMAX 0
SQL_LOGICAL_CHAR OFF
SEQ_CACHE_SIZE 10
ENCRYPT_HDR
ENCRYPT_SMX
ENCRYPT_CDR 0
ENCRYPT_CIPHERS
ENCRYPT_MAC
ENCRYPT_MACFILE
ENCRYPT_SWITCH
CDR_EVALTHREADS 1,2
CDR_DSLOCKWAIT 5
CDR_QUEUEMEM 4096
CDR_NIFCOMPRESS 0
CDR_SERIAL 0
CDR_DBSPACE
CDR_QHDR_DBSPACE
CDR_QDATA_SBSPACE
CDR_SUPPRESS_ATSRISWARN
CDR_DELAY_PURGE_DTC 0
CDR_LOG_LAG_ACTION ddrblock
CDR_LOG_STAGING_MAXSIZE 0
CDR_MAX_DYNAMIC_LOGS 0
DRAUTO 0
DRINTERVAL 30
DRTIMEOUT 30
HA_ALIAS
DRLOSTFOUND $INFORMIXDIR\etc\dr.lostfound
DRIDXAUTO 0
LOG_INDEX_BUILDS
SDS_ENABLE
SDS_TIMEOUT 20
SDS_TEMPDBS
SDS_PAGING
SDS_LOGCHECK 0
UPDATABLE_SECONDARY 0
FAILOVER_CALLBACK
FAILOVER_TX_TIMEOUT 0
TEMPTAB_NOLOG 0
DELAY_APPLY 0
STOP_APPLY 0
LOG_STAGING_DIR
RSS_FLOW_CONTROL 0
ENABLE_SNAPSHOT_COPY 0
SMX_COMPRESS 0
ON_RECVRY_THREADS 2
OFF_RECVRY_THREADS 5
DUMPDIR $INFORMIXDIR\tmp
DUMPSHMEM 1
DUMPGCORE 0
DUMPCORE 0
DUMPCNT 1
ALARMPROGRAM $INFORMIXDIR\etc\alarmprogram.bat
ALRM_ALL_EVENTS 0
#SYSALARMPROGRAM $INFORMIXDIR\etc\evidence.bat
STORAGE_FULL_ALARM 600,3
RAS_PLOG_SPEED 10982
RAS_LLOG_SPEED 0
EILSEQ_COMPAT_MODE 0
QSTATS 0
WSTATS 0
#VPCLASS MQ,noyield
MQSERVER
MQCHLLIB
MQCHLTAB
#VPCLASS jvp,num=1
#JVPJAVAHOME $INFORMIXDIR\extend\krakatoa\jre
#JVPHOME $INFORMIXDIR\extend\krakatoa
JVPPROPFILE $INFORMIXDIR\extend\krakatoa\.jvpprops
JVPLOGFILE $INFORMIXDIR\jvp.log
#JDKVERSION 1.5
#JVPJAVALIB \bin
#JVPJAVAVM jvm
#JVPARGS -verbose:jni
#JVPCLASSPATH $INFORMIXDIR\extend\krakatoa\krakatoa_g.jar;$INFORMIXDIR\extend\krakatoa\jdbc_g.jar
JVPARGS -Dcom.ibm.tools.attach.enable=no
JVPCLASSPATH $INFORMIXDIR\extend\krakatoa\krakatoa.jar;$INFORMIXDIR\extend\krakatoa\jdbc.jar
BUFFERPOOL default,buffers=10000,lrus=8,lru_min_dirty=50.00,lru_max_dirty=60.50
BUFFERPOOL size=4K,buffers=13108,lrus=16,lru_min_dirty=70.00,lru_max_dirty=80.00
AUTO_LRU_TUNING 1
USERMAPPING OFF
SP_AUTOEXPAND 1
SP_THRESHOLD 0
SP_WAITTIME 30
DEFAULTESCCHAR \
LOW_MEMORY_RESERVE 0
LOW_MEMORY_MGR 0
REMOTE_SERVER_CFG
REMOTE_USERS_CFG
S6_USE_REMOTE_SERVER_CFG 0
GSKIT_VERSION
NETTYPE drsoctcp,1,150,NET
If it is a multiprocessor machine, definitely consider turning on MULTIPROCESSOR by setting it to a non-zero value.
The ONCONFIG parameters of greatest interest to you for DSS are those related to Parallel Data Query, or PDQ. The block that commences with MAX_PDQPRIORITY. It is worth perusing the fine manual on these specifically, because the inter-relationship between them and some other parameters is too complex to go into here.
But in essence, DS_MAX_QUERIES is the maxumum number of parallel queries permitted at any time, and DS_MAX_SCANS determines the number of IO threads for scanning your tables. DS_TOTAL_MEMORY determines the amount of memory allocated for PDQ processing, and there is an algorithm in the manual that shows how these variables and the user's PDQPRIORITY setting combine.
You might also want to consider lifting the RA_PAGES and RA_THRESHOLD values - these determine how many pages are read into memory as 'blocks' before grabbing the next batch. If you're wanting to favour table-scans (which generally you do in DSS) then increasing these to something like 256 and 128 might improve performance.
My experience is with SMP and MPP unix boxes, rather than Windows, so I'm not sure how much you can wring out of your architecture, but this is where you want to start.
I would recommend identifying a good DSS query that runs for a decent length of time, and changing one parameter at a time to see the effect. SET EXPLAIN ON is your friend here, too.
One last thing - 11.7 supports table compression, and the tests I've seen show dramatic improvements in a DSS environment with large reads and irregular writes.