Developer Reference for Intel® oneAPI Math Kernel Library for C
p?lange
Returns the value of the 1-norm, Frobenius norm, infinity-norm, or the largest absolute value of any element, of a general rectangular matrix.
Syntax
floatpslange ( char*norm , MKL_INT*m , MKL_INT*n , float*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , float*work );
doublepdlange ( char*norm , MKL_INT*m , MKL_INT*n , double*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , double*work );
floatpclange ( char*norm , MKL_INT*m , MKL_INT*n , MKL_Complex8*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , float*work );
doublepzlange ( char*norm , MKL_INT*m , MKL_INT*n , MKL_Complex16*a , MKL_INT*ia , MKL_INT*ja , MKL_INT*desca , double*work );
Include Files
mkl_scalapack.h
Description
pslange pdlange pclange pzlange The p?lange routine function returns the value of the 1-norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a distributed matrix sub(A) = A(ia:ia+m-1, ja:ja+n-1) .
Input Parameters
norm
(global) Specifies what value is returned by the function :
= ‘M’ or ‘m’: val = max(abs(A_{ij})) , largest absolute value of the matrix A , it s not a matrix norm. = ‘1’ or ‘O’ or ‘o’: val = norm1(A) , 1-norm of the matrix A (maximum column sum), = ‘I’ or ‘i’: val = normI(A) , infinity norm of the matrix A (maximum row sum), = ‘F’ , ‘f’ , ‘E’ or ‘e’: val = normF(A) , Frobenius norm of the matrix A (square root of sum of squares).
m
(global)
The number of rows in the distributed matrix sub(A). When m = 0 , p?lange is set to zero. m ≥ 0.
n
(global)
The number of columns in the distributed matrix sub( A ). When n = 0 , p?lange is set to zero. n ≥ 0.
- a
-
(local). REAL for pslange DOUBLE PRECISION for pdlange COMPLEX for pclange COMPLEX*16 for pzlange .
Pointer into the local memory to an array of size lld_a * LOCc ( ja + n -1) containing the local pieces of the distributed matrix sub( A ).
ia , ja
(global) The row and column indices in the global matrix A indicating the first row and the first column of the matrix sub( A ), respectively.
desca
(global and local) array of size dlen_ . The array descriptor for the distributed matrix A.
- work
-
(local). REAL for pslange DOUBLE PRECISION for pdlange COMPLEX for pclange COMPLEX*16 for pzlange . Array size lwork . lwork ≥ 0 if norm = 'M' or ‘m’ (not referenced), nq 0 if norm = '1' , ‘O’ or ‘o’ , mp 0 if norm = 'I' or ‘i’ , 0 if norm = 'F' , ‘f’ , ‘E’ or ‘e’ (not referenced), where iroffa = mod(ia-1, mb_a), icoffa = mod(ja-1, nb_a) , iarow = indxg2p(ia, mb_a, myrow, rsrc_a, nprow) , iacol = indxg2p(ja, nb_a, mycol, csrc_a, npcol) , mp0 = numroc(m+iroffa, mb_a, myrow, iarow, nprow),nq0 = numroc(n+icoffa, nb_a, mycol, iacol, npcol) ,
indxg2p and numroc are ScaLAPACK tool functions ; myrow , mycol , nprow , and npcol can be determined by calling the function blacs_gridinfo .
Output Parameters
- val
-
REAL for pslange / pclange DOUBLE PRECISION for pdlange / pzlange
The value returned by the function .