[Bug-gsl] Documentation: gsl_spmatrix_alloc_nzmax does not necessarily initialize to all-zeros

[Schmitz Manuel (LBC)]

The GSL documentation says in chapter 41.2 about function 
"gsl_spmatrix_alloc_nzmax":
"This function allocates a sparse matrix of size n1-by-n2 and initializes it to 
all zeros."

However, in the case of the CCS or the CRS storage format, the member "p" is 
not initialized. Calling "gsl_spmatrix_get"  on a freshly allocated matrix may 
yield a nonzero value, because its "p" member may contain offsets to an 
unspecified location in memory.
(Remark: The function gsl_spmatrix_get does not check against the "nz" property 
of the matrix.)

I have attached a modified version of the spmatrix.c file, which does 
initialize the "p" vector when creating a matrix in CCS or CRS storage format. 
But, I would prefer to adjust the documentation rather than the code, because a 
zero-initialized matrix is not always necessary.

Best regards

i.A. Manuel Schmitz

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spmatrix.c
Description: spmatrix.c