Nexus - Pure SHA3 + CPU/GPU + nPoS + 15 Active Innovations + More to Come

[CryptoHobo]

The code has been tested on Linux but not yet on Windows:

https://www.dropbox.com/s/lw7qtp9x5ankill/CoinShieldV1.0.zip?dl=0

GMP version 6.0.0a is the latest version:
https://gmplib.org/

awesome thanks

if anyone's having problems compile the same as the original but do this first:
sudo apt-get install libgmp-dev

[paulthetafy]

I have the new miner running and it appears to be finding blocks...

[METERS] 5 Block(s) Found | Height = 5355 | Difficulty  = 5.181784 | 01:18:43

But I have no mined blocks in my wallet.  Am I missing something?

[ig0tik3d]

any win64 binary of new miner?)

[mumus]

any win64 binary of new miner?)

I've just succeed to compile a windows x64 version of supercomputing's miner using cygwin compiler.
https://mega.co.nz/#!qFk2mYTD!IYBBHazMtqTN8DwTBzKtP8OGdBXRzkJZpXLOkK5IeUA
If it has more dependencies that are not included in the zip file please let me know.

Regarding to performance, I wasn't able to compare it with the linux version yet.

[skunk]

I have the new miner running and it appears to be finding blocks...

[METERS] 5 Block(s) Found | Height = 5355 | Difficulty  = 5.181784 | 01:18:43

But I have no mined blocks in my wallet.  Am I missing something?

i guess they went orphaned...
you should get "[MASTER] Block Accepted By Coinshield Network." when a block is accepted by the network...
i finally found a block with supercomputer's miner, last one was 3 days ago with official miner.

edit: since orphans don't shows up into the wallet anymore, an accepted/rejected ratio information into miner output would help to understand what's going on...

[vedran82]

5 blocks so far, all orphans. Strange, seeing that previous miner had orphans at the beginning but later on I had none.

[merc84]

Diff is rising fast as ppl switch to supercomputering's miner, orphans should settle once diff stabilizes.

[merc84]

any win64 binary of new miner?)

I've just succeed to compile it with cygwin.
https://mega.co.nz/#!qFk2mYTD!IYBBHazMtqTN8DwTBzKtP8OGdBXRzkJZpXLOkK5IeUA
If it has more dependencies that are not included in the zip file please let me know.

Regarding to performance, I wasn't able to compare it with the linux version yet.

Any chance you would compile supercomputing's miner for win also ?

[mumus]

any win64 binary of new miner?)

I've just succeed to compile it with cygwin.
https://mega.co.nz/#!qFk2mYTD!IYBBHazMtqTN8DwTBzKtP8OGdBXRzkJZpXLOkK5IeUA
If it has more dependencies that are not included in the zip file please let me know.

Regarding to performance, I wasn't able to compare it with the linux version yet.

Any chance you would compile supercomputing's miner for win also ?

Sorry if my previous post wasn't clear. At the link above you can find supercomputing's miner compiled for windows x64. I've just used a different compiler (cygwin) compared to previous builds posted on this forum.

[paulthetafy]

I have the new miner running and it appears to be finding blocks...

[METERS] 5 Block(s) Found | Height = 5355 | Difficulty  = 5.181784 | 01:18:43

But I have no mined blocks in my wallet.  Am I missing something?

i guess they went orphaned...
you should get "[MASTER] Block Accepted By Coinshield Network." when a block is accepted by the network...
i finally found a block with supercomputer's miner, last one was 3 days ago with official miner.

edit: since orphans don't shows up into the wallet anymore, an accepted/rejected ratio information into miner output would help to understand what's going on...

Nope that's 400+ Blocks found across > 100 machines / 1000 cores, over 3 hours.  No errors from any of the miners, no orphans showing.  Listtransactions shows no orphans and no new blocks.  Something isn't right.

[ig0tik3d]

I have the new miner running and it appears to be finding blocks...

[METERS] 5 Block(s) Found | Height = 5355 | Difficulty  = 5.181784 | 01:18:43

But I have no mined blocks in my wallet.  Am I missing something?

i guess they went orphaned...
you should get "[MASTER] Block Accepted By Coinshield Network." when a block is accepted by the network...
i finally found a block with supercomputer's miner, last one was 3 days ago with official miner.

edit: since orphans don't shows up into the wallet anymore, an accepted/rejected ratio information into miner output would help to understand what's going on...

Nope that's 400+ Blocks found across > 100 machines / 1000 cores, over 3 hours.  No errors from any of the miners, no orphans showing.  Listtransactions shows no orphans and no new blocks.  Something isn't right.

found 2 blocks with new miner... in debug windows listtransactions show correct mined blocks..

[cestballot]

Code:

:~/crytpo/CoinShield/cpu$ make -f makefile.unix
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -o build/skein.o hash/skein.cpp
hash/skein.cpp: In function ‘int Skein_256_Final(Skein_256_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:199:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein_512_Final(Skein_512_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:397:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein1024_Final(Skein1024_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:594:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein_256_Output(Skein_256_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:683:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein_512_Output(Skein_512_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:712:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein1024_Output(Skein1024_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:741:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -o build/skein_block.o hash/skein_block.cpp
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/KeccakDuplex.o hash/KeccakDuplex.c
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/KeccakSponge.o hash/KeccakSponge.c
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/Keccak-compact64.o hash/Keccak-compact64.c
hash/Keccak-compact64.c: In function ‘void KeccakF1600_StatePermute(void*)’:
hash/Keccak-compact64.c:189:11: warning: invalid conversion from ‘void*’ to ‘tKeccakLane* {aka long long unsigned int*}’ [-fpermissive]
     state = argState;
           ^
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/KeccakHash.o hash/KeccakHash.c
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashInitialize(Keccak_HashInstance*, unsigned int, unsigned int, unsigned int, unsigned char)’:
hash/KeccakHash.c:26:71: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
     result = Keccak_SpongeInitialize(&instance->sponge, rate, capacity);
                                                                       ^
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashUpdate(Keccak_HashInstance*, const BitSequence*, DataLength)’:
hash/KeccakHash.c:39:73: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
         return Keccak_SpongeAbsorb(&instance->sponge, data, databitlen/8);
                                                                         ^
hash/KeccakHash.c:41:83: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
         HashReturn ret = Keccak_SpongeAbsorb(&instance->sponge, data, databitlen/8);
                                                                                   ^
hash/KeccakHash.c:53:72: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
                 ret = Keccak_SpongeAbsorb(&instance->sponge, oneByte, 1);
                                                                        ^
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashFinal(Keccak_HashInstance*, BitSequence*)’:
hash/KeccakHash.c:65:97: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
     HashReturn ret = Keccak_SpongeAbsorbLastFewBits(&instance->sponge, instance->delimitedSuffix);
                                                                                                 ^
hash/KeccakHash.c:67:94: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
         return Keccak_SpongeSqueeze(&instance->sponge, hashval, instance->fixedOutputLength/8);
                                                                                              ^
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashSqueeze(Keccak_HashInstance*, BitSequence*, DataLength)’:
hash/KeccakHash.c:78:70: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
     return Keccak_SpongeSqueeze(&instance->sponge, data, databitlen/8);
                                                                      ^
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -o build/util.o util.cpp
In file included from util.cpp:1:0:
util.h:4:53: fatal error: boost/date_time/posix_time/posix_time.hpp: Aucun fichier ou dossier de ce type
 #include <boost/date_time/posix_time/posix_time.hpp>
                                                     ^
compilation terminated.
make: *** [build/util.o] Erreur 1
manuel@manuel-U36SD:~/crytpo/CoinShield/cpu$ make clean -f makefile.unix 
rm -f coinshield_prime
rm -f build/*.o
manuel@manuel-U36SD:~/crytpo/CoinShield/cpu$ make -f makefile.unix
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -o build/skein.o hash/skein.cpp
hash/skein.cpp: In function ‘int Skein_256_Final(Skein_256_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:199:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein_512_Final(Skein_512_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:397:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein1024_Final(Skein1024_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:594:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein_256_Output(Skein_256_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:683:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein_512_Output(Skein_512_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:712:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
hash/skein.cpp: In function ‘int Skein1024_Output(Skein1024_Ctxt_t*, u08b_t*)’:
hash/skein.cpp:741:29: warning: dereferencing type-punned pointer will break strict-aliasing rules [-Wstrict-aliasing]
         ((u64b_t *)ctx->b)[0]= Skein_Swap64((u64b_t) i); /* build the counter block */
                             ^
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -o build/skein_block.o hash/skein_block.cpp
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/KeccakDuplex.o hash/KeccakDuplex.c
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/KeccakSponge.o hash/KeccakSponge.c
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/Keccak-compact64.o hash/Keccak-compact64.c
hash/Keccak-compact64.c: In function ‘void KeccakF1600_StatePermute(void*)’:
hash/Keccak-compact64.c:189:11: warning: invalid conversion from ‘void*’ to ‘tKeccakLane* {aka long long unsigned int*}’ [-fpermissive]
     state = argState;
           ^
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -fpermissive -o build/KeccakHash.o hash/KeccakHash.c
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashInitialize(Keccak_HashInstance*, unsigned int, unsigned int, unsigned int, unsigned char)’:
hash/KeccakHash.c:26:71: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
     result = Keccak_SpongeInitialize(&instance->sponge, rate, capacity);
                                                                       ^
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashUpdate(Keccak_HashInstance*, const BitSequence*, DataLength)’:
hash/KeccakHash.c:39:73: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
         return Keccak_SpongeAbsorb(&instance->sponge, data, databitlen/8);
                                                                         ^
hash/KeccakHash.c:41:83: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
         HashReturn ret = Keccak_SpongeAbsorb(&instance->sponge, data, databitlen/8);
                                                                                   ^
hash/KeccakHash.c:53:72: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
                 ret = Keccak_SpongeAbsorb(&instance->sponge, oneByte, 1);
                                                                        ^
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashFinal(Keccak_HashInstance*, BitSequence*)’:
hash/KeccakHash.c:65:97: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
     HashReturn ret = Keccak_SpongeAbsorbLastFewBits(&instance->sponge, instance->delimitedSuffix);
                                                                                                 ^
hash/KeccakHash.c:67:94: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
         return Keccak_SpongeSqueeze(&instance->sponge, hashval, instance->fixedOutputLength/8);
                                                                                              ^
hash/KeccakHash.c: In function ‘HashReturn Keccak_HashSqueeze(Keccak_HashInstance*, BitSequence*, DataLength)’:
hash/KeccakHash.c:78:70: warning: invalid conversion from ‘int’ to ‘HashReturn’ [-fpermissive]
     return Keccak_SpongeSqueeze(&instance->sponge, data, databitlen/8);
                                                                      ^
g++ -c -pthread -static-libgcc -static-libstdc++ -Wall -Wextra -Wno-sign-compare -Wno-invalid-offsetof -Wno-unused-parameter -Wformat -Wformat-security -g -DBOOST_SPIRIT_THREADSAFE -DBOOST_THREAD_USE_LIB -I/home/manuel/crytpo/CoinShield/cpu -I/home/manuel/crytpo/CoinShield/cpu/build -I/home/manuel/crytpo/CoinShield/cpu/hash -O2 -MMD -o build/util.o util.cpp
In file included from util.cpp:1:0:
util.h:4:53: fatal error: boost/date_time/posix_time/posix_time.hpp: Aucun fichier ou dossier de ce type
 #include <boost/date_time/posix_time/posix_time.hpp>
                                                     ^
compilation terminated.
make: *** [build/util.o] Erreur 1

I need help for ubuntu compilation
What lib is missing ?

Best

[cestballot]

could you make a short todo list for linux compilation for wallet and miner ? 

Best

[ig0tik3d]

I need help for ubuntu compilation
What lib is missing ?

Best

sudo apt-get install libboost-all-dev

[cestballot]

ok miner look ready, thx

where to get linux wallet ?

Best

[IngsCamps]

Exactly, it is possible to get linux miner ??

[cestballot]

Exactly, it is possible to get linux miner ??

Miner for linux
https://www.dropbox.com/s/lw7qtp9x5ankill/CoinShieldV1.0.zip?dl=0

compilation OK

But where to download linux wallet and how to install ?

Best

[Supercomputing]

I have the new miner running and it appears to be finding blocks...

[METERS] 5 Block(s) Found | Height = 5355 | Difficulty  = 5.181784 | 01:18:43

But I have no mined blocks in my wallet.  Am I missing something?

There seems to be a block submission bug especially when blocks are coming in fast; most likely a carry over from the original miner. I will investigate further and keep you posted.

TESTNET:
Total Number of 4-Chains Found = 2


******* BLOCK FOUND *******


Total Number of 4-Chains Found = 3


******* BLOCK FOUND *******


Total Number of 4-Chains Found = 4


******* BLOCK FOUND *******


Total Number of 4-Chains Found = 5


******* BLOCK FOUND *******


Total Number of 4-Chains Found = 6


******* BLOCK FOUND *******


Preparing for Block Submission...

Preparing for Block Submission...

Preparing for Block Submission...

[skunk]

There seems to be a block submission bug especially when blocks are coming in fast; most likely a carry over from the original miner. I will investigate further and keep you posted.

thank you for your effort, your miner solved 3 block in the past 6 hours on my single i7-3770 box and never crashed!
please put your csd address as a signature so me, like hopefully others, can send you some coins...

[kev7112001]

i see the payouts have decreased by half is that correct