problem with versal (deform.lib) in interactive mode

[stevens@…]

In old versions (2007) the following does work: using versal (deform.lib) in interactive mode one can specify the columns to be used. In newer versions this lead to an error. The procedure interact2 has not been changed. Here is a sample session using the example from the manual:

SINGULAR / Development

A Computer Algebra System for Polynomial Computations / version 4.0.2

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by: W. Decker, G.-M. Greuel, G. Pfister, H. Schoenemann \ Feb 2015

FB Mathematik der Universitaet, D-67653 Kaiserslautern \

LIB "deform.lib"; int p = printlevel; printlevel = 0; ring r1 = 0,(x,y,z,u,v),ds; matrix m[2][4] = x,y,z,u,y,z,u,v; ideal Fo = minor(m,2); list L = versal(Fo,0,p);

INPUT: name of output-file (ENTER = no output, do not use "my"!) ? INPUT: prefix-string of ring-extension (ENTER = '@') ? INPUT:parameter-string

(give a letter corresponding to first new variable followed by the next letters, or 'T(' - a letter + '(' - getting a string of indexed variables) (ENTER = A) :

? INPUT:order-string (local or weighted!) (ENTER = ds) : ? ready: T_1 and T_2 matrix of infinitesimal deformations: 0, u,0, v, -u,0,0, u, 0, 0,u, z, z, y,0, 0, 0, x,-z,0, x, 0,y, 0 weights of infinitesimal deformations ( empty ='not qhomog'): 1,1,1,1

Do you want all deformations? (ENTER=yes)

? no

Choose columns of the matrix (Enter = all columns)

INPUT (number of columns to use as integer-list 'i_1,i_2,.. ,i_t' ): ? 1,2

? converting module to matrix: dimensions must be positive(1x0) ? error occurred in or before deform.lib::interact2 line 850: D = matrix(C,nrows(D),size(C)); ? wrong type declaration. type 'help matrix;' ? leaving deform.lib::interact2 skipping text from ; error at token ) ? leaving deform.lib::versal

[hannes]

fixed with 20a02439b361225625d282efe4ba0927de9c71cc

problem: contruction of a matrix n x 0: Singular 4.0.2.1 allows such matrices, so this is really a fix for 4.0.2 (3.x.x simply does not test here)