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Dec 20, 2016, 10:47:21 AM12/20/16

to libsingular-devel

Hi Hans,

Since 4-1-0, I get the following

SINGULAR / Development

A Computer Algebra System for Polynomial Computations / version 4.1.0

0<

by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Nov 2016

FB Mathematik der Universitaet, D-67653 Kaiserslautern \

> ring r = integer,(x,y,z),lp;

> r;

// coefficients: ZZ

// number of vars : 3

// block 1 : ordering lp

// : names x y z

// block 2 : ordering C

> ideal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

> i;

i[1]=-y2-3y+z2+3

i[2]=-2yz+z2+2z+1

i[3]=xz+yz+z2

i[4]=-3xy+2yz+6z2

> groebner(i);

// ***dError: assume violation at prCopy.cc:195 condition: src_r->cf==dest_r->cf

// ***dError: assume violation at prCopy.cc:179 condition: src_r->cf==dest_r->cf!!longrat:debug:1 in pDebug.cc:253

// ***dPolyReportError: coeff err

occurred at

occurred for poly: !!longrat:im int 2 in longrat.cc:1387

#############################################

No issues with 4-0-3:

SINGULAR / Development

A Computer Algebra System for Polynomial Computations / version 4.0.3

0<

by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Jan 2016

FB Mathematik der Universitaet, D-67653 Kaiserslautern \

> ring r = integer,(x,y,z),lp;

> deal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

? `deal` is undefined

? error occurred in or before STDIN line 2: `3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;`

> ideal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

> groebner(i);

_[1]=164878

_[2]=2z+41856

_[3]=z2-81962z-57679

_[4]=2y-3z3+10z2+5z+8

_[5]=yz+5y+72z4-259z3-120z2-231z

_[6]=y2+3y-z2-3

_[7]=x+2y2z+yz2-2yz-z3-2z2

>

###########################################

The dError stuff comes from:

* https://github.com/Singular/Sources/blob/spielwiese/Singular/iparith.cc#L5784

Indeed the coefficients are explicitly changed to n_Q.

I did not investigate this further yet.

Best,

JPF

Since 4-1-0, I get the following

SINGULAR / Development

A Computer Algebra System for Polynomial Computations / version 4.1.0

0<

by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Nov 2016

FB Mathematik der Universitaet, D-67653 Kaiserslautern \

> ring r = integer,(x,y,z),lp;

> r;

// coefficients: ZZ

// number of vars : 3

// block 1 : ordering lp

// : names x y z

// block 2 : ordering C

> ideal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

> i;

i[1]=-y2-3y+z2+3

i[2]=-2yz+z2+2z+1

i[3]=xz+yz+z2

i[4]=-3xy+2yz+6z2

> groebner(i);

// ***dError: assume violation at prCopy.cc:195 condition: src_r->cf==dest_r->cf

// ***dError: assume violation at prCopy.cc:179 condition: src_r->cf==dest_r->cf!!longrat:debug:1 in pDebug.cc:253

// ***dPolyReportError: coeff err

occurred at

occurred for poly: !!longrat:im int 2 in longrat.cc:1387

#############################################

No issues with 4-0-3:

SINGULAR / Development

A Computer Algebra System for Polynomial Computations / version 4.0.3

0<

by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Jan 2016

FB Mathematik der Universitaet, D-67653 Kaiserslautern \

> ring r = integer,(x,y,z),lp;

> deal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

? `deal` is undefined

? error occurred in or before STDIN line 2: `3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;`

> ideal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

> groebner(i);

_[1]=164878

_[2]=2z+41856

_[3]=z2-81962z-57679

_[4]=2y-3z3+10z2+5z+8

_[5]=yz+5y+72z4-259z3-120z2-231z

_[6]=y2+3y-z2-3

_[7]=x+2y2z+yz2-2yz-z3-2z2

>

###########################################

The dError stuff comes from:

* https://github.com/Singular/Sources/blob/spielwiese/Singular/iparith.cc#L5784

Indeed the coefficients are explicitly changed to n_Q.

I did not investigate this further yet.

Best,

JPF

Dec 20, 2016, 11:13:31 AM12/20/16

to libsingular-devel

For some reason the "s" field is "33" in the coeffs rather than "3" to tell only "z" is used to represent integers:

(gdb) p *id->m[10]->coef

$27 = {

z = {{

_mp_alloc = 1,

_mp_size = 1,

_mp_d = 0x11c895f0

}},

n = {{

_mp_alloc = -1543472123,

_mp_size = 6881280,

_mp_d = 0x6b020072c500780f

}},

debug = 0,

s = 33

}

(gdb) p *id->m[10]->coef->z->_mp_d

$28 = 164878

(gdb)

But as you can see, somehow the seeked for integer is there...

(gdb) p *id->m[10]->coef

$27 = {

z = {{

_mp_alloc = 1,

_mp_size = 1,

_mp_d = 0x11c895f0

}},

n = {{

_mp_alloc = -1543472123,

_mp_size = 6881280,

_mp_d = 0x6b020072c500780f

}},

debug = 0,

s = 33

}

(gdb) p *id->m[10]->coef->z->_mp_d

$28 = 164878

(gdb)

But as you can see, somehow the seeked for integer is there...

Dec 20, 2016, 12:18:55 PM12/20/16

to libsingular-devel

Initialization of integers seem to have changed bw 4-0-x and 4-1-x.

In 4-0-x:

ring r = integer,(x,y,z),lp;

In 4-0-x:

ring r = integer,(x,y,z),lp;

> ideal i = -y^2 - 3*y + z^2 + 3, -2*y*z + z^2 + 2*z + 1,x*z + y*z + z^2, -3*x*y + 2*y*z + 6*z^2;

> groebner(i);

Breakpoint 1, iiExprArithM (res=0x3fffffffcc68, a=0x3fffffff9f50, op=40)

at iparith.cc:8582

8582 iparith.cc: No such file or directory.

(gdb) p *((ideal) a->next->Data())->m[0]->coef

$1 = {z = {{_mp_alloc = 2, _mp_size = -1, _mp_d = 0x3fffb6af49e0}}, n = {{

_mp_alloc = 0, _mp_size = 1, _mp_d = 0x0}}, s = 2}

And in 4-1-x:

(gdb) p *((ideal) a->next->Data())->m[0]->coef

$41 = {z = {{_mp_alloc = 2, _mp_size = -1, _mp_d = 0x10891ee8}}, n = {{

_mp_alloc = 0, _mp_size = 33, _mp_d = 0x18}}, debug = 0, s = 1}

Oops.

at iparith.cc:8582

8582 iparith.cc: No such file or directory.

(gdb) p *((ideal) a->next->Data())->m[0]->coef

$1 = {z = {{_mp_alloc = 2, _mp_size = -1, _mp_d = 0x3fffb6af49e0}}, n = {{

_mp_alloc = 0, _mp_size = 1, _mp_d = 0x0}}, s = 2}

And in 4-1-x:

(gdb) p *((ideal) a->next->Data())->m[0]->coef

$41 = {z = {{_mp_alloc = 2, _mp_size = -1, _mp_d = 0x10891ee8}}, n = {{

_mp_alloc = 0, _mp_size = 33, _mp_d = 0x18}}, debug = 0, s = 1}

Oops.

Dec 20, 2016, 12:49:06 PM12/20/16

to libsingular-devel

It seems the change comes from here:

* https://github.com/Singular/Sources/blob/spielwiese/Singular/LIB/standard.lib#L884

"charstr" now returns "ZZ"... and a different path is taken.

* https://github.com/Singular/Sources/blob/spielwiese/Singular/LIB/standard.lib#L884

"charstr" now returns "ZZ"... and a different path is taken.

Dec 21, 2016, 1:04:32 PM12/21/16

to libsingu...@googlegroups.com

589e8eab0d5415b844ad43ec150a72e4004e1114

But on the other side, a segfault should not occur,

that means there is something more...

Hans

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Dec 22, 2016, 5:34:39 AM12/22/16

to libsingular-devel

On Wednesday, December 21, 2016 at 7:04:32 PM UTC+1, han...@mathematik.uni-kl.de wrote:

On Tue, Dec 20, 2016 at 09:49:06AM -0800, Jean-Pierre Flori wrote:

> It seems the change comes from here:

> *

> https://github.com/Singular/Sources/blob/spielwiese/Singular/LIB/standard.lib#L884

>

> "charstr" now returns "ZZ"... and a different path is taken.

>

Thanks, that was the reason, fixed with commit

589e8eab0d5415b844ad43ec150a72e4004e1114

But on the other side, a segfault should not occur,

that means there is something more...

Yes the reason for the segfault is surely that the idCopyR at

* https://github.com/Singular/Sources/blob/spielwiese/Singular/iparith.cc#L5794

copies the coef as rationals but they are just integers (and in debug mode Singular rants about this discrepancy :

// ***dError: assume violation at prCopy.cc:195 condition: src_r->cf==dest_r->cf

// ***dError: assume violation at prCopy.cc:179 condition: src_r->cf==dest_r->cf!!longrat:debug:1 in pDebug.cc:253

.

So you end up with crap in the newly created coeffs:

So you end up with crap in the newly created coeffs:

(gdb) p *((ideal) a->next->Data())->m[0]->coef

$41 = {z = {{_mp_alloc = 2, _mp_size = -1, _mp_d = 0x10891ee8}}, n = {{

_mp_alloc = 0, _mp_size = 33, _mp_d = 0x18}}, debug = 0, s = 1}

Look at the _mp_alloc = 0, _mp_size = 33, _mp_d = 0x18.

When it gets deallocated, it just booms.

Best,

JPF

When it gets deallocated, it just booms.

Best,

JPF

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