Singular

I want to execute Singular with an online command in silent mode. I ran a test with an online command and it works out fine, but still can not manage to run it in silent mode.

Thanks in advance

Cheers

Is it this what you want?

Then start Singular by

See: 3.1.6 Command line options
http://www.singular.uni-kl.de/Manual/la ... .htm#SEC26

I do not think so. We need a command similar to the C command which uses & to run programs

with no interruption. We are using Plural in computing a rank matrix and we have been thrown off

many times with no answer; we suspect it is the time limitation imposed by our server. Our administrator

tells us this is not and we have also checked the CPU porcentage of use of our computation and this

does not exceed a 2 to 3 % of the CPU. It is also funny that in computing the matrix with polinomial

entries when saving the matrix computation and recalling it back to save computation time with the


WRITE command it actually takes longer than it we compute it right at the moment and use it in

the program interactively. We in fact one to compute the rank of this matrix.

B. regards,

To get some help, provide an example.
Otherwise it is not comprehensible what the problems are.

Dear Gorzel:

The following is a toy model.

LIB "nctools.lib";
LIB "central.lib";
LIB "ring.lib";
LIB "linalg.lib";

// Define the ring
ring r0 = complex,(x1,x2),dp;
ring r1 = (0,t), (y1,y2), dp;
matrix C[2][2];
matrix D[2][2];
C[1,2]=1;
def S=nc_algebra(C,D);
setring S;S;
ideal Basis = PBW_eqDeg(1);

// Define a matrix for a linear transformation.
matrix A[2][2];
A[1,1]=1; A[1,2]=t^2; A[2,1]=t^2; A[2,2]=t^4;

int rankA = mat_rk(A);
write (":w rankA.m", rankA);

// Now generate the ideal of images.

ring r2 = 0, (z1,z2), dp;

fetchall(S);

poly h(1)= A[1,1]*z1 + A[1,2]*z2;
poly h(2)= A[2,1]*z1 + A[2,2]*z2;

map F = r0, h(1..2);

ideal Image = h(1..2);
module M = linearMapKernel(Image); M;
ideal K = linearCombinations(Basis, M); K;
write (".w K.m", K);

exit;


Now, we want to do the same, but the matrix we are working with is 2100 X 1001, so it seems to require a lot of memory. The system administrator suggest us to either try to run Singular using the 8 Cores of the machine (i.e. a parallel process) and /or run Singular in silent mode. To achieve the last goal we wrote a file, called toy-model.m, with the same instructions as above, and try to run it as Singular toy-model.m &
hopping for it to run at the background, without showing anything, just writing the answer in a file, but we fail...

Thanks in advance for your help.

PS. You can also see a previous note of october 2, 2009, posted also by Nieto, called vectorspace and relations, answered by
Oleksandr

It is not clear to me what you mean by

How long did the computation run?

As far as I understand, you see the problem that displaying a huge
amount of data to stdout (say on the screen) slows down the computation.
So you decided to let it run in background mode,
hoping that it would then run faster. But writing a lot of data as ASCII
always takes time, also when you write it to a file.

Instead of using & for the background job you should do the following.

1.) Write a the beginning of your script (called toy-model.m) the command
echo =1;
2.) Erase all those lines which only display unnecessary output
(or put a // in front)
3.) It will be useful to put some short commands like
" Starting Step 1 ";

" Step 3 finished";

Then start Singular as a nohup job (this means: 'do not hang up')

Now you can logout from the computer but the job will run forever
unless somebody switches the machine off, or you will kill the job.

You may always login on the machine where you have started the job.
Calling the unixcommand top you will see the time, CPU, memory, and process ID of the job.

Moreover you can inspect with less or tail the file toy-model.log and
you will see at which stage the computation is.

Hope this helps. For questions concerning Plural, I am not the right
person, there Oleksandr (malex) may help.

Thanks Gorzel, it seems to work