#include <math.h>
#include "superlu_ddefs.h"
Functions/Subroutines | |
double | pdlangs (char *norm, SuperMatrix *A, gridinfo_t *grid) |
File name: pdlangs.c History: Modified from lapack routine DLANGE
double pdlangs | ( | char * | norm, | |
SuperMatrix * | A, | |||
gridinfo_t * | grid | |||
) |
Purpose =======
PDLANGS returns the value of the one norm, or the Frobenius norm, or the infinity norm, or the element of largest absolute value of a real matrix A.
Description ===========
PDLANGE returns the value
PDLANGE = ( max(abs(A(i,j))), NORM = 'M' or 'm' ( ( norm1(A), NORM = '1', 'O' or 'o' ( ( normI(A), NORM = 'I' or 'i' ( ( normF(A), NORM = 'F', 'f', 'E' or 'e'
where norm1 denotes the one norm of a matrix (maximum column sum), normI denotes the infinity norm of a matrix (maximum row sum) and normF denotes the Frobenius norm of a matrix (square root of sum of squares). Note that max(abs(A(i,j))) is not a matrix norm.
Arguments =========
NORM (input) CHARACTER*1 Specifies the value to be returned in DLANGE as described above. A (input) SuperMatrix* The M by N sparse matrix A. GRID (input) gridinof_t* The 2D process mesh. =====================================================================